International Structure Commission

Leo, A.J. (1975) Calculation of partition coefficients useful in the evaluation of relative hazards of various chemicals in the environment. In Symposium on Structure-Activity Correlations in Studies of Toxicity and Bioconcentration with Aquatic Organisms. G.D. Veith and D.E. Konasewich, Editors, International Joint Commission, Ontario, Canada. 

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. 

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. 

STRUCTURE 1 CAS REGISTRY NUMBER 147-24-0 TSCACANDIDATE LIST R062-2752 U.S. INTERNATIONAL TRADE COMMISSION PHS-149CARCINOGENS B0276 NIOSH RTECS KR70000... 

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

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

To date, approximately 125 different microporous structures have been reported to the International Zeolite Commission (IZC) for structure codes [6] and the interested reader can access this information via the following website http //www.iza-structure.org. Each microporous material is assigned a three-letter code by the IZC (the IZC code will be used throughout the remainder of this chapter). These microporous materials are distinguished by the connectivity of the framework atoms that determine the size and dimensionality of the pores and/or cages that they possess. 

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. 

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. 

Fig. 5.2. Soybean complex Structure of the industry. Source U.S. International Trade Commission, 2003 and author s calculations.

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. 

MFI stands for Mobil Five and ZSM stands for Zeolite Socony Mobil. Detailed information about the structure-type codes can be found on the homepage of the Structure Commission of the International Zeohte Association (IZA) at http //www.iza-structure.org. 

For three-letter codes cf. Ref. [235], Note A few abbreviations, as for instance CLIN, are not acronyms (three-letter codes) approved by the Structure Commission of the International Zeolite Association (IZA), but just convenient designations. 

Source Web of Science (papers) and Derwent Innovation Index (patents), October 2008, used with permission. The inset shows the number of Framework Type Codes (FTCs) collected in the different editions of the Atlas of Zeolite Framework Types plus the number of FTCs already approved by the Structure Commission of the International Zeolite Association in November 2008 (http //www.iza-structure.org/)... 

Zeolites and related microporous materials offer abundant chemical diversity. Over the past three decades, many new synthetic zeolites have been discovered. The Structure Commission of The International Zeolite Association have approved 145 framework types (November 2003). In addition, there are numerous other zeolites with structures that are not yet known or are only hypothetical. The goals of this article are to briefly mention the main categories and principal industrial uses of zeolites, before providing more detailed discussions of molecular sieving and redox reactions. 

Considering only frameworks made up entirely of tetrahedral comer-sharing TO4 species, full details of all the structure types are collected, refereed and published by the Structure Commission of the International Zeolite Association. The most recent publication indicates that around 170 framework types (each of which is given a unique three-letter code) have been unambiguously identified and both hardcopy publications (in particular the so-called Atlas of Zeolite Framework Types ) and the continuously updated structural summary on the web site (www.iza-structure.org) are indispensable resources for the researcher in this field. 

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