Structural Commission

Meier, W.M. Olson, D.H. "Atlas of Zeolite Structure Types" Structure Commission of the Inti. Zeolite Assn., Polycrystal Book Service, Pittsburgh, PA, 1978. 

The nomenclature of zeolites is rather arbitrary and follows no obvious rules because every producer of synthetic zeolites uses his/her own acronyms for the materials. However, as mentioned before, at least the structure types of the different zeolites have a unique code. For example, FAU represents Faujasite-type zeolites, LTA Linde Type A zeolites, MFI Mobile Five, and BEA Zeolite Beta. The structure commission of the International Zeolite Association (IZA) is the committee granting the respective three-letter codes [4], Some typical zeolites, which are of importance as catalysts in petrochemistry, will be described in the following sections. 

The IZA has several established Commissions. The Structure Commission formed in 1977 has published four editions of the Atlas of Zeolite Structure Types (1978, 1987, 1992, 1996) and two subsequent editions in the Atlas of Zeolite Framework Types (2001, 2007). An up-to-date version is maintained on the World Wide Web at the IZA Structure Commission web site (http //www.iza-structure.org). Subsequently commissions were established in catalysis (1998), synthesis (1992), ordered mesoporous materials (2001) and natural zeolites (2001). The synthesis commission published a volume, Verified Syntheses of Zeolitic Materials , in 1998, with a second revised edition in 2001 (http //www.iza-structure.org). 

Not all frameworks built from tetrahedra as described above are considered to be zeolites. Dense phases are not considered to be zeolites, only those phases with some porosity. Generally, materials with pores accessible by windows defined by six T-atoms or less (six-rings) are not considered to be zeolites. In fact, the boundary between zeolites and dense phases is somewhat nebulous. lUPAC defines [1] zeolites as a subset of microporous or mesoporous materials containing voids arranged in an ordered manner and with a free volume larger than a 0.25 nm diameter sphere. The Structure Commission of the International Zeolite Association uses the criterion of framework density (T-atoms per lOOOA ) with the maximum framework density for zeolites ranging from 19 to 21. 

Figure 2.5 Cumulative number of framework types by year approved by the IZA Structure Commission and given a three letter code (assignment of dates before 1992 is uncertain).

The framework type codes accepted by the IZA Structure Commission gives a convenient way to discuss general structural features of materials but it is impor-... 

Framework and polyhedral figures were drawn using ATOMS V6.2 by Shape Software. Channel system diagrams were generated using the 3D drawing option at the IZA Structure Commission web site [4]. 

International Zeolite Assodation Structure Commission (2002) www. iza-structure.org (accessed August 2007). 

This web site also contains an interactive powder pattern calculator that allows the user to change the input and variables for a powder pattern calculation. This book was typeset using UTj X with the standard computer modern typeface. The LT X file and associated postscript plots were generated with a C++ program written by M. M. J. Treacy. We wish to acknowledge the assistance and collaboration of the members of the IZA Structure Commission for proofreading the manuscript and providing additional information. We are indebted to our employers (Arizona State University, and Air Products Chemicals, Inc.) for support of this project, and to our wives Laura and Carol for their patience and support. 

Published on behalf of the Structure Commission of the International Zeolite Association... 

Meier, W. M. and Olson, D. H. "Atlas of Zeolite Structure Types", Structure Commission of the Int. Zeolite Association 1978, 37-... 

Zeolites are now defined as solids that possess a framework of tetrahedra which are all corner-sharing and include a degree of opermess such as channels or cavities. Each framework type is issued a unique three letter code by the Structure Commission of the International Zeolite Association. " At the end of February 2007, there were 176 framework types. This definition does not specify atom types. 

W. M. Meier and D. H. Olson, Atlas of Zeolite Structure Types, 2nd ed., Structure Commission of the International Zeolite Commission, Butterworths, London, 1988. 

IZA (International Zeolite Association) zeolite database is maintained by IZA structure commission. Available on-line at http //www.iza-structure.org/databases/. 

International Zeolite Association Structure Commission Website www.iza-structure.org/... 

Atlas of Zeolite Framework Types. Structure Commission of the International Zeolite Association, 5th Edn, eds Ch. Baerlocher, W.M. Meier, and D.H. Olson, Elsevier, 2001... 

GIS). A three letter code (e.g. GIS) is assigned to confirmed framework types by the Structure Commission of the International Zeolite Association according to rules set up by an 1UPAC Commission on Zeolite Nomenclature [3,4]. The codes are normally derived from the name of the zeolite or type material , e.g. FAU from the mineral faujasite, LTA from Linde Type A, and MFI from ZSM-5 (Zeolite Socony Mobil - five). Information pertinent to these framework types is published in the Atlas of Zeolite Framework Types [5] and on the internet at http //www.iza-strncture.org/databases/. As new codes are approved, they arc announced on the IZA Structure Commission s WWW pages (http //www.iza-structure.org/) and included in the internet version of the Atlas. As of January 2005, 161 zeolite framework types had been confirmed by the Structure Commission. In this chapter, all references to materials whose framework types are known will be accompanied by the appropriate three letter code in boldface type. 

As mentioned at the beginning of this chapter, essential structural information for all zeolite framework types to which the Structure Commission has assigned a three-letter code is... 

Powder diffraction techniques are used on a routine basis by many zeolite scientists. Probably the most common application is the use of a powder diffraction pattern as a fingerprint in the identification of synthesis products. Ideally, a laboratory should have a set of standard zeolite patterns measured on the in house instrument for direct comparison. For laboratories without such a set of patterns or for those whose set is incomplete, the Synthesis Commission of the IZA has published experimental patterns for some zeolites in the book entitled Verified Syntheses ofZeolitic Materials [35] (also available on the internet at http //www.iza-synthesis.org/), and the Structure Commission has published a book entitled Collection of Simulated XRD Powder Patterns for Zeolites [36], which contains at least one representative powder diffraction pattern for each known framework type. An up-to-date internet version of the latter that includes data for newly approved framework types, is maintained at http //www.iza-structure.org/databases/. 

W. M. Meier and D. H. Olson, Atlas of Zeolite Structure Types, Structure Commission of the International Zeolite Association, 1978 It has recently been demonstrated that the use of synchrotron x-ray sources permits single crystal studies to be carried out on much smaller samples. P. Eisenberger, J. B. Newsam, M. E. Leonowicz, and D. E. W. Vaughan, Nature 309 45 (1984) The use of Rietveld refinement techniques allows better. structural information to be obtained from powder diffraction data. W. I. F. David, W. T. A. Harrison, and M. W. Johnson, in High Resolution Powder Diffraction, Materials Science Forum, vol. 9 (C. R. A. 

The International Zeolite Conference is one of the pillars on which the identity of the zeolite community stands, at the same level of the definitions of zeolite structures provided by the Structure Commission of the International Zeolite Association, the dedicated journal which was Zeolites and is now Microporous and Mesoporous Materials, and the meetings of several national and regional zeolite associations. 

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