Full opinion text
OPINION LONGOBARDI, Chief Judge. The Plaintiff Mobil Oil Corporation (“Mobil”) alleges that Defendant Amoco Chemicals Company (“Amoco”) is infringing patents owned by Mobil. These patents cover compositions known as ZSM-5 zeolites and their use as catalysts. Amoco denies that it infringes Mobil’s patents and also alleges that Mobil’s patents are invalid. I. TECHNICAL AND FACTUAL BACKGROUND A. Zeolites Natural and synthetic zeolites are crystalline materials with a variety of useful characteristics. They currently are used in a wide variety of applications including: catalytic cracking in the petroleum industry, catalysis of hydrocarbon reactions, drying of refrigerants, removal of carbon dioxide and sulfur compounds from natural gas, recovering radioactive ions from radioactive waste solutions, curing of plastics and removal of atmospheric pollutants. D.W. Breck, Zeolite Molecular Sieves 2 (1974) Defendant’s Exhibit (“DX”) 1122. The study of zeolites began in 1756 with the discovery of stilbite, a naturally occurring zeolite. The word zeolite means “boiling stone” and refers to the fact that naturally occurring zeolites contain water which vaporizes or boils when the zeolites are heated. R.M. Barrer FRS, Hydrothermal Chemistry of Zeolites 2 (1982) (DX 1125); Docket Item (“D.I.”) 126 at 693. Further studies indicated that zeolites exhibited other remarkable properties. In 1840, it was discovered that zeolite crystals could be dehydrated and then rehydrated without changing the transparency or morphology of the crystal. The adsorption of gases by dehydrated zeolites was discovered in 1909. In 1925, a publication taught that dehydrated chabazite, a naturally occurring zeolite, would absorb vapors of some liquids but not vapors of other liquids. D.W. Breck, Zeolite Molecular Sieves 14 (1974) (DX 1122). Researchers also discovered that certain zeolites, such as gmelinite and chabazite, had similar adsorption properties while other zeolites, such as mordenite, exhibited different properties. Id. at 18. The ability of certain naturally occurring zeolites to selectively adsorb certain vapors, as well as their ability to act as catalysts and cation exchangers, made them valuable candidates for commercialization. These properties are largely attributable to the structure of the zeolites. Zeolites are crystals made up of three dimensional networks of atoms. These networks are largely open structures containing cavities and channels of various sizes. Currently at least sixty-four different zeolite networks or topologies are known to exist. W.M. Meier & D.H. Olson, Atlas of Zeolite Structure Types 1 (2nd ed. 1987), Plaintiff’s Exhibit (“PX”) 857. Any sample of a particular zeolite will always have the same topology as any other sample of the same zeolite. In naturally occurring zeolites, the networks are primarily made from three elements: oxygen (“0”), silicon (“Si”) and aluminum (“Al”). More precisely, these three elements are arranged in tetrahedral units of SÍO4 and AIO4 and these units are linked together to form the network of the crystal. In an individual SÍO4 tetrahedron, the silicon is at the center of the tetrahedron and is bonded to four oxygen atoms which make up the corners of the tetrahedron. An AIO4 tetrahedron is analogous except that aluminum rather than silicon occupies the center of the tetrahedron. The atom in the center of each tetrahedron was referred to as the “t-atom” by several of the witnesses at the trial and the Court will adopt that nomenclature. These t-atoms and their corresponding oxygens combine in different ways to produce a variety of network structures. A visible zeolite crystal is made up of millions of repetitions of a basic network pattern. The smallest piece of the crystal that can be repeated to produce the entire network is called the “unit cell.” Therefore, the unit cell of a zeolite defines its crystal structure. Although the technique was not available when the study of zeolites began, today researchers can determine if a structure of new zeolite matches one of the known topologies. This is done by taking an X-ray diffraction pattern of the new zeolite and comparing it to known patterns inherent in other zeolites. The composition of any given zeolite is not as constant as its crystal structure. Unlike compounds such as water or carbon dioxide, zeolites cannot be assigned specific chemical formulas. Each t-atom shares its oxygen atoms with an adjacent t-atom. The common oxygen atoms link the tet-rahedra into a network. When the t-atoms in a zeolite are solely aluminum and silicon, the ratio of the aluminum atoms plus silicon atoms to oxygen atoms is one to two. However, the ratio of silicon atoms to aluminum atoms may not be exactly the same for two samples of a given zeolite. Originally, it was not possible to directly measure the aluminum and silicon content of zeolites. In order to measure the silicon and aluminum in a sample, the sample would be heated in the presence of air to convert the elements to their oxides. D.I. 126 at 633. Using this method, silicon is converted to silica, Si04 and aluminum is converted to alumina, A1203. Researchers expressed the amounts of silicon and oxygen in a zeolite sample in terms of a silica to alumina ratio and this practice is still the standard practice in the field. Id. at 635. In order to calculate the silicon to aluminum ratio for a sample, one must divide the silica to alumina ratio by two. It is also important to note that the high silica to alumina ratios indicate low amounts of aluminum and low silica to alumina ratios indicate high amounts of aluminum. A discussion of zeolites would not be complete without referring to the non-framework components of zeolites, namely water and associated cations. If a zeolite is not dehydrated it will contain a certain amount of water within the channels and pores of the framework. Zeolites also contain positively charged species called cations. Zeolites require non-framework cations to maintain electrochemical neutrality. Oxygen ions each carry a formal charge of negative two. Silicon, when it is bonded to oxygen, generally carries a formal charge of positive four. In a zeolite with no aluminum atoms, the ratio of silicon atoms to oxygen atoms would be 1 to 2. Each silicon with its formal charge of positive four would balance two oxygen atoms with their individual formal charges of negative two. Therefore, such a zeolite would be electrochemically neutral. The introduction of aluminum into the zeolite crystal structure makes things more complicated from the electrochemical point of view. Aluminum atoms in zeolites carry a formal charge of positive three. Unlike silicon, a single aluminum ion cannot completely balance the charge from two oxygen ions; one negative charge will remain. Therefore, the framework of a zeolite is generally anionic, that is, it carries a negative charge. Each aluminum t-atom contributes to this overall deficit of positive charges in the structure. In order to correct this deficit, zeolites contain non-framework positive species called cations. The number of positive charges that must be supplied by the cations is directly proportional to the number of aluminum t-atoms in the zeolite. Naturally occurring zeolites are all alu-minosilicates. Therefore, discussing their structure and composition solely in terms of silicon, aluminum and oxygen is appropriate. However, with the advent of synthetic zeolites, the story becomes a bit more complicated. Researchers attempted to synthesize zeolites as early as the 1800s. D.I. 124 at 252-53. A entirely new zeolite named zeol-ite A was synthesized by researchers at Union Carbide in 1948. Zeolite A is used in detergents, in thermopane windows and in automobile air conditioners. D.I. 127 at 917. The next synthetic zeolites were zeol-ite X and zeolite Y which were also synthesized by scientists at Union Carbide. Id. at 918. Zeolite X and Y have the same structure but different compositions. Zeolite X has a silica to alumina ratio of about two and Zeolite Y has a silica to alumina ratio between roughly four and seven. Id. at 919-20. Zeolite X is used in separating nitrogen from oxygen to produce oxygen used for medical purposes. Zeolite Y is used as a cracking catalyst to convert crude oil to petroleum products. Id. at 921. Another notable synthetic zeolite is ZK-4 which was synthesized by Mobil researchers. This zeolite represented an advance in zeolite synthesis because it was the first time that a zeolite material was made in the presence of an organic cation. Prior to that time zeolites were synthesized by mixing a source of silica, a source of alumina and a source of sodium or potassium. Id. at 923. ZK-4 has the same structure as Zeolite A but has a higher silica to alumina ratio. Id. at 924. The organic cation used in the synthesis of ZK-4 was tetramethy-lammonium. Id. at 923. Zeolite Beta was synthesized by Mobil researchers and patented in 1967. Id. at 927. It was also synthesized by using an organic cation. The organic cation used was tetraethylammonium which is the next member in a series of amines which begins with tetramethylammonium. Id. at 926. Zeolite beta was an important development in the field of zeolites because it could be synthesized with a very high silica to alumina ratio from 5 to 150. Id. at 928. Before the synthesis of zeolite beta, morden-ite with a silica to alumina ratio of approximately 11 was the most silica rich zeolite known. Id. at 931-32. A high silicon content is desirable because it increases the thermal stability of the zeolite. Id. at 921. A higher silicon content can also correspond to a higher catalytic activity. Id. at 922. Using tetrapropylammonium, the next member in the series of amines, researchers at Mobil synthesized and patented a new zeolite called ZSM-5. Although the preparation of ZSM-5 is similar to the preparation of zeolite beta, the two zeolites have different topologies. The ZSM-5 zeolites possess a topology which had not been previously discovered. The framework of ZSM-5 exhibits channels which run in two directions. In one direction the channels are relatively straight and in the other direction the channels are undulated. The size of the pores in ZSM-5 makes it an ideal catalyst for many reactions. Mobil researchers applied for and obtained patents on the ZSM-5 family of zeolites and their use as catalysts. These ZSM-5 patents also taught that other elements could be incorporated into the zeolite framework. Specifically, gallium (“Ga”) could be substituted for aluminum and germanium (“Ge”) could be substituted for silicon. PX 1 at 729. Researchers began exploring other elemental substitutions. In 1981, a researcher at Amoco received a patent for materials which have boron incorporated into the ZSM-5 framework. DX 1. In 1982, researchers at Union Carbide patented a family of crystalline materials which contain aluminum and phosphorous and no silicon. D.I. 127 at 953. In 1983, a United States Patent was issued on an titanosilicate material with the ZSM-5 structure. Mt. Ta-rasmasso et al, U.S. Pat. No. 4,410,501. Since that time, materials have been prepared which incorporate many other elements, such as chromium, manganese and sulfur into zeolite frameworks. Id. at 961-62. These new compounds have apparently created a nomenclature problem in the zeol-ite field. Because naturally occurring zeolites were all aluminosilicates, experts in the field disagree as to whether the term zeol-ite can be applied to substances which have a zeolite-like crystal structure but contain little or no aluminum or silicon. At least one expert has suggested that it is more appropriate to call these materials molecular sieves and reserve the term zeolite for only those materials which have the appropriate topology and are aluminosilicates. R. Szostak, Molecular Sieves Principles of Synthesis and Identification 2 (1989). The Court declines to accept this suggestion and will use the term zeolite to denote only a characteristic topology. B. Zeolites as Catalysts Catalysts are materials which facilitate chemical reactions but remain essentially unchanged as a result of the reactions. For example, the addition of a catalyst to a mixture of substances may allow a reaction to take place which would have not occurred in the absence of the catalyst. In other cases, the presence of a catalyst may allow a reaction to proceed more quickly, proceed at a lower temperature or produce higher yields of desired products. The suitability of a zeolite as a catalyst for a particular reaction depends upon the topology and the composition of the zeolite. The topology of a zeolite provides a means to sort a mixture of various compounds and allows only certain molecules in the mixture to undergo reactions. For example, a zeolite with a channel size of 5 angstroms will allow molecules smaller than 5 angstroms to enter the zeolite and will exclude molecules which are larger than 5 angstroms. In addition, if two or more small molecules react inside the channels of the zeolite to produce a molecule which was larger than 5 angstroms, the large molecule will be trapped inside the framework of the zeolite. See D.I. 126 at 621-23. The ability of a zeolite to exclude or retain molecules of a certain size is referred to as shape selectivity. In an effort to classify zeolites according to their topologies, researchers sometimes divide zeolites into three categories: small, medium and large pore zeolites. D.I. 127 at 915. Researchers can also conduct experiments to determine the constraint index of a zeolite. The constraint index is a number which gives scientists information about the ability of certain sized molecules to pass through the channels and pores of a zeolite. PX 725, col. 3. This information about the structure of a zeolite is helpful in determining if the zeolite might be a useful catalyst for a particular reaction. Id. The composition of a zeolite also plays a role in determining its effectiveness as a catalyst. The framework and non-framework components of a zeolite can provide an active site for chemical reactions. In the zeolite ZSM-5, the framework aluminum atoms with their associated non-framework cations are thought to provide acidic sites which can catalyze many different reactions. D.I. 124 at 88. C. Hydrocarbon Conversion Reactions Zeolite catalysts are used to aid the production of certain compounds from petroleum refining. The reforming process used in oil refining generates, among other things, a mixture of compounds called the Cg aromatic stream. D.I. 124 at 218. The main components of the Cg aromatic stream are para-xylene, ortho-xylene, meta-xylene and ethyl benzene. Id. at 218-19. All of these compounds are hydrocarbons, that is, they contain only the elements hydrogen and carbon. Para-xylene is a valuable compound because it is used to manufacture polyesters such as Dacron. Id. at 217. The other components in the Cg aromatic stream are not used for this purpose. Id. at 218. The three xylenes are closely related compounds; they are called isomers of each other. Id. at 216. Conversion of or-tho-xylene and meta-xylene into para-xylene was accomplished on a small scale as early as 1890. The reaction, called xylene isomerization, used a non-zeolite aluminum containing catalyst. D.I. 130 at 1432. When the demand for para-xylene became great enough, plants were designed to allow continuous xylene isomerization of the Cg aromatic stream. The first plant was built in the mid-1950s by Imperial Chemical Industries Company (“ICI”). Id. at 1432-33. Following each reaction, the para-xylene would be stripped from the mixture and the compounds which were not converted to para-xylene would be returned to the reaction vessel for another reaction. The ICI process used a silica/alumina catalyst, also a non-zeolitic material. Unfortunately, the presence of ethyl benzene in the mixture interfered with the xylene isomerization process. D.I. 124 at 219. If the ethyl benzene were left in the Cg aromatic stream, it would eventually build up to a point where it would cause the plant to shut down. Id. 221. The ethyl benzene was removed from the Cg aromatic stream before conducting the xylene isom-erization reaction. This was done by distilling the ethyl benzene from the Cg aromatic stream. Due to the similarity in the boiling points between ethyl benzene and the xy-lenes and, due to the large scale of these reactions, this distillation step required very tall distillation towers and was extremely expensive. D.I. 124 at 220; D.I. 130 at 1434. Another problem with this process was that the catalyst became fouled very quickly and the plant had to be shut down every few days to clean the catalyst. D.I. 130 at 1434. Eventually, a new process called Octafin-ing was commercially installed in 1958. PX 727, col. 1, lines 4-5. Octafining uses a catalyst containing platinum on silica and alumina. D.I. 130 at 1435. A second generation Octafining catalyst also contained the zeolite mordenite. Id. at 1437. Oetaf-ining had two advantages over the method used by ICI. The Octafining process consumes or converts the ethyl benzene in the reactor simultaneously with the xylene isomerization reaction. This eliminated the need to use the expensive distillation step. D.I. 124 at 223; D.I. 130 at 1435. In addition, the catalyst does not foul as quickly as the catalyst used by ICI. Typically, plants using the Octafining process could run for about three months before the catalyst needed to be cleaned. D.I. 124 at 228-29. Although Octafining was an improvement over the previous technology, it still had many limitations. The process is expensive because it has to be run at fairly high temperatures, 830 to 900 degrees Fahrenheit (“°F”) and requires the use of relatively large quantities of hydrogen. Id. at 225. In addition, platinum, one of the components of the catalyst, is quite expensive. Id. at 227. The Octafining process has to be run at relatively low space velocities or rates of feed which means that the production rate is low. D.I. 124 at 226. The plants using the Octafining process had to be shut down for a period of several days three or four times a year to clean the catalyst. Eventually, cleaning would not restore the catalyst and it had to be replaced perhaps as often as once a year. Id. at 228-29. In an effort to avoid some of these disadvantages, several companies developed alternative processes for simultaneous xylene isomerization/ethyl benzene conversion. For example, UOP developed a process called ISOMAR which currently is used in approximately twenty-four units world-wide. The temperature and pressure used in the ISOMAR process are described as moderate. D.I. 130 at 1439-40. Amoco developed a process for simultaneous xylene isomerization/ethyl benzene conversion called Amocofining. Amoco used the Amocofining process from 1973 until 1977. The Amocofining catalyst contained alumina, platinum and mordenite, a zeolite. Pretrial Order, D.I. 107, Stipulated Fact Number 17, Exhibit G. Mobil also developed a process for simultaneous xylene isomerization/ethyl benzene conversion which used a catalyst containing one of the members of the patented ZSM-5 family of zeolites. D.I. 124 at 233. A patent issued to a Mobil scientist on this process in December of 1974. One embodiment of this process is called MVPI. MVPI refers to “Mobil Vapor Phase Isom-erization.” D.I. 107, Stipulated Fact Number 20. MVPI represented an improvement over Octafining because the MVPI catalyst ages at a much slower rate than the Octafining catalyst. It has a lifetime of up to six years. D.I. 124 at 235. The MVPI catalyst also requires less frequent regenerations than the Octafining catalyst. Id. at 236. The MVPI process uses less hydrogen than the Octafining process and has a greater throughput. Id. at 236-37. In addition, the shape selectivity of the MVPI process gave greater yields of desired products than the Octafining process. Id. at 243. On October 22, 1976, Mobil granted to Amoco a license to practice the patented MVPI process and a license of Mobil technical information. The agreement is entitled the “VPI Process License Agreement.” D.I. 107, Stipulated Fact Number 18, Exhibit G. On the same date, Mobil granted a lease for VPI catalysts to Amoco. That agreement is entitled simply “Lease.” Id., Stipulated Fact Number 19, Exhibit G. Amoco used the leased MVPI catalyst in xylene isomerization/ethyl benzene conversion process at Amoco’s Decatur Number 2 facility from August, 1978, to May, 1980, at the Texas City Number 1 facility from October, 1976, to April, 1983, and at Amoco’s Texas City Number 2 facility from February, 1977, to February, 1984. Id., Stipulated Fact Number 21, 22, 23. Thereafter, using its own AMS-1B family of zeolites, Amoco developed three commercial zeolites called AMS-1B-1, AMS-1B-2 and AMS-1B-3. The “1” preceding each B represents the ZSM-5 type topology. AMS stands for “Amoco Molecular Sieve” and the B represents boron. The number following each B represents a particular molecular sieve. Id., Stipulated Fact Number 27. There are also three commercial Amoco catalysts. The catalyst containing AMS-1B-1 is called AMSAC-1203M. AMSAC-2400 contains AMS-1B-2, and AMSAC 3400 contains AMS-1B-3. Id., Stipulated Fact Number 28. In May of 1980, Amoco changed the xylene isomerization/ethyl benzene conversion process used at its Decatur Number 2 facility from a process using MVPI catalyst to a process using AMSAC-1203M catalyst. Id., Stipulated Fact Number 24. In April of 1983, Amoco began practicing a xylene isomerization/ethyl benzene conversion process at the Texas City Number 1 facility using AMSAC-2400 catalyst. Id., Stipulated Fact Number 25. In February of 1984, Amoco replaced the MVPI catalyst at the Texas City Number 2 facility with AMSAC-3400. Id., Stipulated Fact Number 26. Therefore, each of Amoco’s AMS-1B zeolites or sieves and each of Amoco’s AMSAC catalysts has been used commercially. Id., Stipulated Fact Number 29. II. PROCEDURAL HISTORY Mobil’s complaint alleges that Amoco infringed two of Mobil’s United States Patents relating to ZSM-5. D.I. 1. The complaint also alleged that Amoco’s infringement of these patents was willful. Mobil also alleged that this was an exceptional case. The answer denied that Amoco infringed Mobil’s patents. Amoco’s counterclaim sought a declaration of non-infringement, invalidity and unenforceability with respect to the two patents in the complaint and seventeen other Mobil patents. In addition, Amoco asked this Court to enjoin Mobil from terminating the license agreement and award Amoco costs and reasonable attorney’s fees. This Court has jurisdiction over the subject matter of the claims and counterclaims in this action pursuant to 28 U.S.C. § 1331, § 1338(a) and § 2201. Venue is proper under 28 U.S.C. § 1391 and § 1400(b). Pursuant to a stipulation and order dated July 28, 1987, all claims and counterclaims based on twelve of the nineteen patents were dismissed. D.I. 54. Another stipulation and order dated May 31, 1988, severed and stayed all claims and counterclaims relating to three of the remaining patents and claims relating to Amoco’s alleged use of Mobil technical information. The issue of the amount of damages was bifurcated and stayed. D.I. 80. On February 25, 1991, the Court granted Mobil’s motion to amend the complaint to include counts of infringement and willful infringement with regard to two of the four remaining patents which were not identified in Mobil’s original complaint. D.I. 124 at 4. In a three week trial, the Court heard testimony from seventeen witnesses appearing at trial and received deposition excerpts from at least ten other witnesses into evidence. The trial transcript exceeds thirty-three hundred pages and the exhibits admitted into evidence number more than eight hundred. It is upon this record that the Court bases its decision. III. ISSUES PRESENTED AT TRIAL Mobil is the sole owner of the four disputed patents. D.I. 107, Stipulated Fact Numbers 6, 9, 11, 14. Two of the patents were issued to Robert J. Argauer and George R. Landolt. Patent number 3,702,-886 (“the ’886 patent”) is a compostion patent directed toward the ZSM-5 family of zeolites while patent number Re. 29,857 (“the ’857 patent”) is concerned with the catalytic conversion of hydrocarbons through use of the ZSM-5 zeolites. Patent number 3,856,872 (“the '872 patent”), issued to Roger A. Morrison, claims a xylene isomerization process which uses ZSM-5 catalysts. A patent issued to Warren W. Kaeding, number 4,049,573 (“the ’573 patent”), is directed toward a zeolite catalyst compositions which contain oxides of boron or magnesium. Mobil alleges that Amoco literally infringes claim one of the ’886 patent, claim one of the ’857 patent, claim six of the ’872 patent and claims one, two and eight of the ’573 patent. Mobil also alleges that Amoco infringes claims one and three of the ’886 patent, claims one and two of the ’857 patent, claim six of the ’872 patent and claims one, two and eight of the ’573 patent under the doctrine of equivalents. Mobil alleges that Amoco’s infringement of all four patents was willful. Mobil also asserts that three of the patents, the ’886,-’857 and ’872 patents, are pioneer patents. Amoco denies infringing any of the patents willfully, literally or under the doctrine of equivalents. In addition, Amoco asserts that the ’886 and the ’857 patents are invalid under 35 U.S.C. § 102(b). Amoco alleges that the ’573 and the ’872 patents are invalid under 35 U.S.C. § 103. Amoco also alleges that all four patents, if construed to cover Amoco’s zeolites and catalysts, fail under 35 U.S.C. §§ 112 para. 1 and 112 para. 2. The Court also heard evidence on the issue of whether the licensing agreement between Mobil and Amoco was still in effect. Mobil alleges that the license was not in effect because it had been breached by Amoco. Amoco denies breaching the license and contends that it was still in effect because Mobil had never terminated the license. In addition, Amoco alleges that even if its AMS-1B zeolites or AMSAC catalysts are determined to infringe Mobil’s composition patents, the existence of the MVPI licensing agreement between Mobil and Amoco prevents a finding that Amoco infringed Mobil’s process patents. IV. INFRINGEMENT Section 271 of Title 35 of the United States Code provides in pertinent part that “whoever without authority makes, uses or sells any patented invention, within the United States during the term of the patent therefor, infringes the patent.” Infringement may be found only if every limitation in a claim is found in the accused product or process. Jurgens v. McKasy, 927 F.2d 1552, 1560 (Fed.Cir.1991). Literal infringement occurs when every limitation in the claim is found in the accused product or process. Even if there is no literal infringement, infringement under the doctrine of equivalents may be found if an equivalent of every limitation in the claim exists in the accused product or process. Id. “The issue of infringement raises at least two questions: (1) what is patented and (2) has what is patented been made, used or sold by another.” Fromson v. Advance Offset Plate, Inc., 720 F.2d 1565, 1569 (Fed.Cir.1983). In order to resolve the issue of infringement, a court must initially determine the proper scope of the claims of the patent. Once the claims have been construed, the court must examine the defendant’s allegedly infringing activity to determine if it falls within the scope of the claims. Jurgens, 927 F.2d at 1560; American Standard, Inc. v. Pfizer, Inc., 722 F.Supp. 86 (D.Del.1989). Claim construction is a question of law and the application of properly construed claims to a defendant’s product or process is a question of fact. Loctite Corp. v. Ultraseal Ltd., 781 F.2d 861, 866 (Fed.Cir.1985). A plaintiff must establish infringement by a preponderance of the evidence. Phillips Petroleum Co. v. United States Steel Corp., 673 F.Supp. 1278, 1344 (D.Del.1987), aff'd, 865 F.2d 1247 (Fed.Cir.1989). Even if a patented invention is entitled to “pioneer” status, the method used to determine infringement remains the same. Texas Instruments, Inc. v. U.S. Int’l Trade Com., 846 F.2d 1369, 1370 (Fed.Cir.1988). A. Scope of the Claims The claims of a patent should be construed as they would have been understood by one of ordinary skill in the art at the time the invention was made. Loctite Corp., 781 F.2d at 867. In interpreting the claims, a court should consider several sources of information including: the literal language of the claims, the patent specification, the prosecution history of the patent and the testimony of experts. Id. at 866-67; American Standard, Inc., 722 F.Supp. at 92. 1. One of Ordinary Skill in the Art The person of ordinary skill in the art is a hypothetical person who is placed in the enviable position of being aware of all of the relevant prior art. Custom Accessories, Inc. v. Jeffrey-Allan Industries, Inc., 807 F.2d 955, 962 (Fed.Cir.1986). The level of skill of the inventors of the patents at issue is not a determinative factor. Id. In determining the level of ordinary skill in the art, a court may consider several factors. These include the kinds of problems existing in the art, the known solutions to the problems, the rate at which new inventions are made in the field, the complexity of the technology and the educational level of working scientists in the field. Id. Of course, all of these factors may not always be present and the importance of each factor will vary from case to case. Id. at 962-63. In the present case, the art was concerned with synthesizing and characterizing zeolites with new topologies and new compositions. The petroleum refining art was concerned with finding zeolites which would be useful catalysts for reactions. Increasing the yields of the xylene isomeri-zation/ethyl benzene conversion process was one specific concern. New zeolites were being synthesized quite quickly. It took longer to develop commercial processes which used the new synthetic zeolites. For example, Mobil began licensing the MVPI process approximately ten years after the discovery of ZSM-5. Following the discovery of AMS-1B, it took Amoco approximately three years to begin commercial use of the AMSAC catalysts. Even in 1969, the technology in the field was quite complex. For example, characterization of new synthetic zeolites required knowledge of X-ray diffraction techniques and methods of conducting elemental analysis. Formulation of zeolites into commercially viable catalysts and understanding their activity was, and still is, a difficult task. D.I. 138 at 3308. The plants used to conduct the hydrocarbon conversion reactions on a commercial scale were also quite sophisticated. See PX 727 schematics. Apparently, the level of education of scientists working in the field ranged from individuals with a bachelor of science degree to those with doctoral degrees. One expert witness for Mobil testified that one of ordinary skill in the art would have a bachelor’s degree in chemistry or engineering and two to three years of experience in the field. D.I. 124 at 103. One expert witness for Amoco testified that one of ordinary skill in the art would have a doctorate or the equivalent of a doctorate in chemistry and several years of experience. D.I. 128 at 1138. Another expert for Amoco described one of ordinary skill in the art as someone with a Masters degree in chemical engineering and a few years of experience. D.I. 130 at 1459-60. Based upon the problems in the field, the complexity of the equipment and techniques used and the evidence that many of the workers in the field had either advanced degrees or many years of experience, the Court believes that a chemist with a bachelor’s degree and two years of experience would generally not possess the level of ordinary skill in the art. On the other hand, someone with a Ph.D. and several years of experience would probably have much more than the ordinary level of skill. Therefore, the Court concludes that the hypothetical person of ordinary skill in the art should be someone with at least a Masters degree in chemistry or chemical engineering or its equivalent, two or three years of experience working in the field. 2. Claims of the ’886 Patent The ’886 patent was filed as application number 865,472 on October 10, 1969. It is a continuation-in-part (“c-i-p”) of abandoned application Serial Number 630,993 which was filed on April 14, 1967. The patent, entitled “Crystalline Zeolite ZSM-5 and Method of Preparing the Same”, issued on November 14, 1972. Claim one of the ’886 patent states: [What is claimed is a] crystalline alumi-nosilicate zeolite having a composition in terms of mole ratios of oxides as follows: 0.9 ± 0.2 M2/n0:Al203:Y Si02:z H20 wherein M is at least one cation having a valence n, Y is at least 5 and z is between 0 and 40, said aluminosilicate having the X-ray diffraction lines of Table 1 of the specification. Argauer ’886 Patent, PX 1, col. 14, lines 50-57. Claim three is dependent upon claim one and provides: [What is claimed is a] crystalline alumi-nosilicate zeolite according to claim 1 having a composition, in terms of mole ratios of oxides, as follows: 0.9 ± 0.2 M2/nO:Al2O3:5-100 Si02:z H20 wherein M is at least one cation having a valence n, and z is between 0 and 40. Id. at lines 60-67. The claims contain two main limitations. The claims specify that the aluminosilicate zeolites must have certain X-ray diffraction lines and a certain formula. The X-ray diffraction pattern identifies the crystalline structure of the compounds. The formula defines their chemical composition. Claims one and three cover only those zeolites having all of the X-ray diffraction lines identified in table 1 of the ’886 patent. Table 1 specifies several lines and a margin of error for each one. The relative intensity of the lines is also identified. The parties do not seriously dispute that the X-ray pattern defined in Table 1 correlates to the ZSM-5 structure. Therefore, this limitation requires little construction by the Court. Recently, the ZSM-5 crystal structure has been designated as “MFI.” W.M. Meier & D.H. Olson, Atlas of Zeolite Structure Types 100 (2nd ed. 1987). This term was not used at the time the patents were issued. In the interests of avoiding confusion between the structure and the claimed materials, however, the Court will use the term MFI to denote the structure of ZSM-5 compounds or any other compounds with the same topology. It is the composition limitation of the claims which is vigorously disputed. Although there were a multitude of arguments presented, these arguments were directed toward two main issues: (1) Do the claims require that a minimum amount of aluminum be present in the compositions, and (2) do the claims cover compositions containing framework elements other than silicon, aluminum and oxygen. (a) The Minimum Aluminum Requirement Claim one recites a silica to alumina ratio, expressed as Y, of “at least five” while claim three specifies a silica to alumina ratio of 5 to 100. As discussed supra, a low aluminum content corresponds to a high silica to alumina ratio and a high aluminum content corresponds to a low silica to alumina ratio. For example, an alu-minosilicate zeolite with a silica to alumina ratio of 100 would contain less than 1 percent of aluminum. D.I. 126 at 639. Claim three expresses a lower and an upper limit for the silica to alumina ratio. Claim one expresses only a lower limit which corresponds to a maximum amount of aluminum. The question before the Court is whether claim one should be construed to require a minimum aluminum content or upper limit on the silica to alumina ratio. If the Court determines that an upper limit is required, then the Court must determine what value to assign the upper limit. Both claims one and three are directed toward an “aluminosilicate zeolite.” Amoco contends one of ordinary skill in the art in 1969 would understand this term to limit the claims to zeolites containing substantial amounts of aluminum. Amoco suggests that the upper limit on claim one should be construed to be approximately 200. Mobil objects to this construction of the claim. Claim one contains both the term “alumi-nosilicate” and the phrase “silica to alumina ratio” which the Court believes would imply to one of ordinary skill in the art in 1969 that the claimed zeolites contained some aluminum. The “alumino” in “alumi-nosilicate” refers to aluminum. Furthermore, a silica to alumina ratio would be meaningless if a compound contained no aluminum. Id. at 721-22. Therefore, the language of claim one indicates that it is limited to materials containing some amount of aluminum. A review of the patent specification also supports this conclusion. The summary of the invention describes the invention as “a novel family of ultrastable synthetic siliceous materials hereinafter designated as ‘Zeolite ZSM-5’ or simply ‘ZSM-5.’ ” PX 1, col. 2, lines 13-14. The summary of the invention states that ZSM-5 can be formed using either aluminum or gallium. Id. at lines 24-25. The specification states that “ZSM-5 is preferably formed as an alumi-nosilicate.” Id., col. 5, line 74. This suggests that “aluminosilicate ZSM-5” is a subset of ZSM-5 zeolites, specifically a ZSM-5 zeolite containing aluminum and silicon. Therefore, the Court concludes that claim one covers only compounds containing some amount of aluminum. In determining what is the upper limit on the silica to alumina ratio recited by claim one, the Court begins its analysis by examining the language of the claim. The claim specifies a silica to alumina ratio of “at least 5.” This implies that there is no upper limit or a limit of infinity on the silica to alumina ratio. Since the presence of some minimal amount of aluminum is required for a compound to be an alumino-silicate, the silica to alumina ratio must have some upper limit that is not infinity. In determining what one of ordinary skill in the art would consider as the upper limit of the ratio, the Court next refers to the remainder of the patent. Claim three, which is dependant upon claim one, recites a silica to alumina ratio of 5 to 100. Because claim one should be construed as providing broader coverage than claim three, the Court concludes that the upper limit on the silica to alumina ratio recited in claim one must be greater than 100. Nothing in the remainder of the patent states or suggests a specific upper limit for claim one. The summary of the invention states in pertinent part: The family of ZSM-5 compositions has the characteristic X-ray diffraction pattern set forth in Table 1, hereinbelow. ZSM-5 compositions can also be identified in terms of mole ratios of oxides, as follows: 0.9 ± 0.2 M2/„0:W203:5-100Y02:z h2o wherein M is at least one cation, n is the valence of said cation, W is selected from the group consisting of aluminum and gallium, Y is selected from the group consisting of silicon and germanium, and z is from 0 to 40. Id., col. 2, lines 17-27. The summary of the invention also states that in a preferred form ZSM-5 has the formula “0.9 ± 0.2 M2/nO:Al2O3:5-100 Si02:z H20.” Id., col. 2, lines 27-30. From this summary, one might conclude that the preferred range for the silica to alumina ratio was 5 to 100. The table discussing the broad, preferred and particularly preferred embodiments of the compositions, however, does not support this conclusion. The table describes silica to alumina ratios of 5 to 100 as broad and states the preferred range is 10 to 60. Id., col. 5, table 3. The Court concludes that the range of 5 to 100 should be considered the broad range of the silica to alumina ratios. The preferred formula recited in the summary of the invention should be interpreted as a statement that aluminum and silicon are preferred over gallium and germanium for ZSM-5 compositions rather than a statement about preferred silica to alumina ratios. The examples of the patent support this interpretation. All of the examples of synthesis in the patent recite the addition of an independent aluminum source to the reaction mixture. If one exactly follows the examples set out in the patent, the zeolites produced will have silica to alumina ratios between approximately 11 and 83. D.1.129 at 1234. Based upon the patent as a whole and the differences between claim three and claim one, one of ordinary skill in the art would also understand that the upper limit on silica to alumina ratio of claim one should be greater than 100 and less than infinity. No specific number between these values is suggested by the language of the patent. The prosecution history of the ’886 patent contains information which is relevant to this analysis. PX 723. Prior to the second office action, claim one did not contain a composition formula or the term aluminosilicate. That form of the claim was rejected, inter alia, on the ground of insufficient disclosure. The examiner stated the claim placed “no limit on the composition of the zeolite product whereas the specification only discloses the preparation of zeolites having a composition, for example, comprising silica and alumina in molar ratios of from 5 to 100.” D.I. 124 at 69. In response to the examiner, claim one was amended in several respects. The phrase “crystalline aluminosilicate zeolite” was substituted for the phrase “crystalline zeolite compositions”, and a composition formula reciting a silica to alumina ratio of “at least 5” was added to the claim. Id. at 75. The attorney prosecuting the patent stated: It is noted that the silica to alumina ratio is recited as being “at least 5” rather than inserting in these claims an upper limit of 100. It is respectfully submitted that to require the applicants to place an upper limit on the silica to alumina ratio would deprive them of a potentially important part of their inventive contribution. Id. at 79. Claim one eventually issued without an upper limit on the silica to alumina ratio. From this exchange the Court finds support for the proposition that the upper limit on claim one should be substantially higher than 100. A consideration of the prior art is also helpful in setting an upper limit on the silica to alumina ratio of claim one. Prior to the synthesis of ZSM-5, zeolite beta was the most aluminum poor zeolite known in the art. Zeolite beta can be synthesized with silica to alumina ratios which range from 5 to 150. D.I. 127 at 928. The broadest composition claim for zeolite beta recites a silica to alumina ratio of greater than 5 but less than 100. DX 9, col. 10, lines 38-47. A comparison of claim one of the zeolite beta patent to claims one and three of the ’886 patent would suggest to one of ordinary skill in the art that claim one of the ’886 patent covered zeolites with silica to alumina ratios which were substantially higher than 100. Amoco relies on the Dwyer and Jenkins patent, U.S. Patent Number 3,941,871, for the proposition that one skilled in the art in 1969 would interpret claim one of the ’886 patent to cover only compounds with silica to alumina ratios of 200 or less. The Dwyer and Jenkins patent was filed in 1973 and issued in 1976. DX 59. It is owned by Mobil and is entitled “Crystalline Silicates and Method of Preparing the Same.” The Dwyer and Jenkins patent is directed toward MFI zeolites which are essentially free of Group IIIA metals, such as aluminum or gallium. DX 59, col. 2, lines 8-10. The zeolites claimed in the Dwyer and Jenkins patent have silica to alumina ratios in excess of 200. Id., col. 11, lines 45-50. If the Court could rely on this subsequently filed patent to aid it in interpreting the claims of the ’886 patent, this opinion would be substantially shorter. However, the Court believes that such a reliance would be improper. This patent does not fit under any of the sources this Court is to use in construing claims; it is not prior art to the ’886 patent nor is it expert testimony of what one of ordinary skill in the art would have known in 1969. Although the facts in this case are distinguishable from the facts in Water Technologies, the Court finds the language of the Court of Appeals for the Federal Circuit persuasive: We must construe claims “in light of the claim language, the other claims, the pri- or art, the prosecution history, and the specification.” We see no reason why arguments made by a different attorney prosecuting later patent applications for a different inventor should be used to issue an earlier-issued patent_ Water Technologies Corp. v. Calco, Ltd., 850 F.2d 660, 667 (Fed.Cir.) (citation omitted, emphasis in original), cert. denied, 488 U.S. 968, 109 S.Ct. 498, 102 L.Ed.2d 534 (1988). Similarly, this Court sees no reason why the later filed patent should be used to limit the claims of the ’886 patent. The Court also heard expert testimony regarding how one of ordinary skill in the art would have understood these claims. An expert called by Amoco, Dr. Szostak, testified that one of ordinary skill in the art would believe that attempts to synthesize ZSM-5 with silica to alumina ratios above 150 would produce amorphous or non-crystalline material. D.I. 129 at 1236-37. Upon cross examination, this expert conceded, however, that there was nothing in the ’886 patent which discouraged one of ordinary skill in the art from attempting such syntheses. Id. at 1235. This expert called by Amoco also testified that one definition of aluminosilicate zeolite requires that there be on average at least one aluminum atom per unit cell of the zeolite. D.I. 130 at 1393-95. The MFI structure has 96 t-atoms in the unit cell. Id. at 1400. Therefore, in order for an MFI zeolite to have approximately one aluminum per unit cell, the silica to alumina ratio would have to be approximately 190 or less. D.I. 128 at 1013. If the Court accepted this definition of aluminosilicate, the Court would construe claim one of the ’886 patent to have an upper limit on the silica to alumina ratio of approximately 200. Cross-examination of this witness revealed that the unit cell definition was not widely used in the art in 1969. D.I. 129 at 1218-26. For example, the zeolite beta patent filed in 1964 refers to zeolite beta as an aluminosilicate. DX 9. It is now known that some of the zeolite Beta compositions described in that patent have less than one aluminum atom per unit cell. D.I. 129 at 1226. The witness testified that the issue of what should be properly called an alumi-nosilicate zeolite did not present itself until 1977 when researchers began making zeolites which contained little or no aluminum. Id. An expert witness called by Mobil, Dr. Cotton, disagreed with much of this testimony. The expert for Mobil testified that a silica to alumina ratio of 100 corresponded to a sample which contained less than one percent of aluminum. D.I. 126 at 639. The expert stated that one of ordinary skill in the art would assume that the aluminum played a negligible role in stabilizing the structure of ZSM-5 because it was present in such small amounts. Id. at 643. This expert also disagreed that a unit cell definition was appropriate. He testified that there is no real world significance that can be attached to the value of an average of 1 aluminum atom per unit cell. D.I. 138 at 3245-46. Construing the upper limit on the silica to alumina ratio of claim one as 200 based upon the evidence presented at trial would be improper. The unit cell of ZSM-5 was not known at the time the ’886 patent application was filed or even at the time the patent issued. See PX 626. The testimony offered by Amoco did not suggest that anything known in 1969 would lead one of ordinary skill in the art in 1969 to believe that claim one should be limited to that particular number. Therefore, the Court must reject Amoco’s argument that the upper limit of claim one should be construed to be 200. Nor can the Court accept Mobil’s argument that a material is an aluminosilicate if it contains “a detectable amount” aluminum. Due to the advances in the art of chemical analysis, what is detectable in 1991 may not have been detectable in 1969. Allowing the upper limit of claim one to be “the silica to alumina ratio corresponding to a detectable amount of aluminum” would create a claim with a scope that improperly grows over time. Cf. 35 U.S.C. § 251 (no reissued patent shall enlarge the scope of claims unless applied for within 2 years of the grant of original patent). Dr. Cotton testified that one of the characteristic properties of aluminosilicate zeolites is ion exchange. D.I. 126 at 720. It was known in the art in 1969 that the exchangeable cations were associated with the aluminum in aluminosilicate zeolite structures. See, e.g., DX 9, 170; PX 1, background of the invention section. Therefore, if zeolite contained enough aluminum to render the material capable of ion exchange or catalytic activity, then one of ordinary skill in the art in 1969 would be likely to identify the material as an alumi-nosilicate zeolite. The Court does not have enough evidence to find the absolute minimum amount of aluminum which would cause this level of activity or the corresponding absolute upper limit on the silica to alumina ratio of claim one. However, the Court did hear evidence indicating that the difference between a silica to alumina ratio of 100 and 2,000 would correspond to only a small difference in the composition of an alumi-nosilicate zeolite. An aluminosilicate zeol-ite with a silica to alumina ratio of 100 would contain 46.268 percent silicon and 0.445 percent aluminum by weight; an MFI aluminosilicate zeolite with a silica to alumina ratio of 2300 would contain 46.689 percent silicon and 0.039 percent aluminum by weight. D.I. 126 at 564; PX 1302. The expert also testified that an MFI aluminosi-licate zeolite with a silica to alumina ratio as great as 2,000 would exhibit catalytic activity. Id. at 655. Based on this evidence the Court construes the upper limit on the ratio of silica to alumina ratio in claim one to be on the order of 2,000. The Court realizes that an MFI aluminosilicate zeolite with a significantly lower aluminum content might exhibit ion exchange capability or catalytic activity and would be recognized by one of ordinary skill in the art in 1969 as containing aluminum. However, there was insufficient testimony offered at trial to allow the Court to choose any higher silica to alumina ratio. (b) The Absence of Other Framework Elements Requirement The next claim construction issue is whether the term aluminosilicate and the compositional formulas in claims one and three of the ’886 patent limit the claims to MFI zeolites without substantial amounts of framework elements other than aluminum, silicon and oxygen. Of particular interest to the parties is whether MFI zeolites with framework boron are covered by the claims. Amoco contends that the claims do not cover MFI zeolites with significant amounts of other framework elements. Mobil argues that the claims are open to the inclusion of other framework elements, specifically boron. (i) Is “Aluminosilicate Zeolite” Exclusionary? The term aluminosilicate zeolite is used many times throughout the patent. The specification of the ’886 patent indicates that the term “aluminosilicate zeol-ite” is a narrower term than “zeolite.” See, e.g., PX 1, col. 1, lines 43-45 (“Certain zeolitic materials are ordered porous crystalline aluminosilicates_"); id., col. 5, lines 74-75 (“ZSM-5 is preferably formed as an aluminosilicate”). The patent contains the following description of aluminosilicate zeolites: Such molecular sieves include a wide variety of positive ion-containing crystalline aluminosilicates, both natural and synthetic. These aluminosilicates can be described as a rigid three-dimensional network of SÍO4 and AIO4 in which the tetrahedra are cross-linked by the sharing of oxygen atoms whereby the ratio of the total aluminum and silicon atoms to oxygen is 1:2. Id., col. 1, lines 55-61. Amoco argues that the ratio of the total number of aluminum and silicon atoms to oxygen atoms in a zeolite cannot be one to two unless there are no other atoms within the zeolite framework. Mobil contends that this part of the specification merely explains how the t-atoms in zeolites share oxygen atoms to form the framework. Mobil argues that reading this portion of the specification to require the exclusion of other framework atoms would improperly impose a stoichiometric theory of chemistry on zeolite which are non-stoichiometric materials. The term aluminosilicate is used in all of the claims of the ’886 patent including claim fifteen which states in pertinent part: “A method of preparing a crystalline alumi-nosilicate zeolite as defined in claim 1 which comprises preparing a mixture containing ... an oxide of a metal selected from the group consisting of aluminum and gallium, [and] an oxide of a metal selected from the group consisting of silicon and germanium.” Id., col. 15, lines 32-38. Mobil contends that this claim, which contemplates the use of gallium or germanium to synthesize an aluminosilicate zeolite, indicates that aluminosilicate zeolite is not an exclusionary term. The Court concludes that the term alumi-nosilicate zeolite is not used in a consistent manner throughout the patent. Part of this inconsistency may be due to the fact that the term aluminosilicate zeolite was added to all of the claims of the ’886 patent rather late in the prosecution history of the patent. PX 723 at 75-78. The prosecution history of the ’886 patent reveals that claim one was originally rejected under sections 102, 103 and 112. Claim three, which was claim four in the original application, contained a compositional formula when the application was filed. Id. at 40. This claim was rejected under only sections 102 and 103. Id. at 67-73. Following the final rejection, the application was amended to insert aluminosilicate throughout the claims. Id. at 75-78. The compositional formula was also added to claim one. Id. at 77-78. These additions overcame the section 112 rejection but did not overcome the section 102 and 103 rejections. Id. at 91. Amoco contends that this history indicates that the inventors were required to narrow their claims to cover only alumino-silicate zeolites. Citing Mannesmann Demag Corp. v. Engineered Metal Products Co., 793 F.2d 1279 (Fed.Cir.1986). Amoco argues that the claims cannot be construed to cover zeolites containing other framework elements. Mobil denies that the amendments worked a prosecution history estoppel. Citing Environmental Designs, Ltd. v. Union Oil Co., 713 F.2d 693 (Fed. Cir.1983), cert. denied, 464 U.S. 1043, 104 S.Ct. 709, 79 L.Ed.2d 173 (1984), Mobil argues that limiting the claims is inappropriate because the amendments were made to overcome the section 112 and not the section 102 or section 103 rejections. The extent to which a claim is narrowed by an action taken before the Patent and Trademark Office depends upon the nature of the action and the reasons for it. See Mannesmann Demag Corp., 793 F.2d at 1284-85. Because claim three, which contained a compositional formula, was never rejected under section 112, the Court concludes that the formula was more important than the term aluminosilicate in overcoming the section 112 rejection of claim one. Although it is clear that claim one would not have issued without reciting a more definite composition, there is nothing in the prosecution history which indicates that the addition of the term aluminosili-cate was a required amendment. Nor is there any indication in the prosecution history of whether the term is open or exclusionary. A study of the prior art indicates that if other framework elements were present in an aluminosilicate zeolite, then it was customary to specifically mention those elements. For example, the introduction to U.S. Patent Number 3,328,119 issued to Robson in 1967, states that the invention relates to “synthetic crystalline alumino-silicate zeolites containing minor proportions of boria incorporated within their crystal lattice structure.” DX 119, col. 1, lines 13-15. In that patent, claim one refers to “a synthetic crystalline aluminosili-cate zeolite containing boria as an integral part of its crystal framework.” Id., col. 8, lines 38-39. This patent did not use the term aluminosilicate zeolites in an exclusionary manner. However, claims of the patent specifically indicated that the boron was incorporated into the zeolite framework. The term galliosilicate zeolite as used in U.S. Patent Number 3,431,219 also illustrates this principal. In March of 1969, the patent directed toward galliosilicate zeolites issued to one of the inventors of the ’886 patent. DX 180. In that patent, the inventor used the term galliosilicate zeolite to refer to zeolites which contained some gallium and which might or might not contain aluminum. See, e.g., id., col. 1, lines 12-15. Some of the claimed galliosili-cates had very small amounts of gallium incorporated into the framework. For example, the number of framework gallium atoms might be as little as one ninth of the number of aluminum atoms. The claims were directed toward galliosilicates which expressly indicates the presence of gallium in the framework of the zeolites. The expert opinions offered on what one of ordinary skill in the art would have understood by the term aluminosilicate zeolite were contradictory. The experts called by Mobil testified that the term alu-minosilicate zeolite did not preclude other elements from being present in the framework. See, e.g., D.1.124 at 191; D.1.126 at 657-58. Experts called by Amoco testified that aluminosilicate zeolite as used in the '886 patent would exclude the presence of other elements in the zeolite framework. See, e.g., D.1.133 at 2056; D.1.137 at 2944-45. It is not clear from the testimony whether the experts were giving their definitions of an aluminosilicate zeolites or the definition that would have been understood by one skilled in the art in 1969. Therefore, the expert witness testimony on this issue was of limited usefulness to the Court. Although the term aluminosilicate would not suggest that there were absolutely no other framework atoms in the zeolite, it is likely that one of ordinary skill in the art would expect another term such as borosili-cate or galliosilicate to be used if the framework of the zeolite contained substantial amounts of other framework elements. This is especially true in light of the fact that the naturally occurring zeolites have substantially only aluminum, silicon and oxygen in their framework. The Court is mindful that this interpretation of aluminosilicate zeolite does not harmonize all of the uses of aluminosilicate zeolite in the ’886 patent. However, given contrasting uses of crystalline zeolite and alumino-silicate zeolite in the specification and the practice in the prior art of specifically mentioning other framework elements, the Court believes that the term aluminosili-cate would imply to one of ordinary skill in the art in 1969 the absence of substantial numbers of other framework elements. (ii) Are the Compositional Formulas Exclusionary? Both claim one and claim three of the ’886 patent recite a zeolite having a composition in terms of mole ratios of oxides. These ratios are expressed as formulas. The formula recited in claim one is: 0.9 ± 0.2 M2/nO : A1203: Y Si02: z H20. The formula recited in claim three is: 0.9 ± 0.2 M2/nO : A1203:5-100 Si02: z H20. The compositional formulas list only aluminum, silicon and oxygen as framework elements of the claimed composition. The expression “0.9 ± 0.2 M2/nO” found in both claims refers to the non-framework cations in the zeolite. T