IZA-SC Rules for Framework Type Code Assignment
The following is a set of rules to be applied by the Structure Commission of the International Zeolite Asssociation (IZA-SC) in assigning a three-letter code to a new framework type.  The materials of interest are generally defined as open 4-connected 3-dimensional nets, which have the general (approximate) composition AB2, where A is a tetrahedrally connected atom and B is any 2-connected atom, which may or may not be shared, between two neighboring A atoms.  Inclusion of other microporous materials is left to the discretion of the IZA-SC, depending on the interest of the molecular sieve science community at large. RULES
(i)	The IZA-SC is the only body that can coordinate the assignment of a code to such frameworks.  The framework types are idealized, with no reference to actual materials, symmetry, composition, etc. and, therefore, ONLY refer to the connectivity.
(ii)	The code for a 4-connected 3-dimensional framework type shall consist of three capital letters.  Other frameworks of interest shall be indicated by a (-) in front of the code.
(iii)	The three letters of the code shall be mnemonic and must refer to an actual material (i.e. the type material).  These materials are chosen to be:
		- mineral names (rules of the International Mineralogical Association followed)
		- commonly accepted synthetic material types
		- in the absence of the above, the workers who first determined the structure have priority in assigning the name
(iv)	No mnemonic code can be assigned without the structure being determined with the following exception: For "polytypic" materials, codes can be assigned as useful.  Such codes shall be marked with an asterisk.
(v)	Codes of framework types which turn out to be in error are discredited.  Later use of the code is not permitted.
(vi)	For all cases where a decision of the Structure Commission is required, a two thirds majority vote of the full commission shall be required.  Such votes are taken verbally at a meeting of the Structure Commission or are done in writing on the initiative of the Chairperson and Co-chairperson.  All evidence substantiating a new framework type must accompany the ballot.  The members are obliged to respond to this request within one month and the Chairperson and Co-chairperson will make all possible effort to solicit replies from all members.