# Do we need a crystallography tag?

This question is brought about by this post:

Determine the coordinates of octahedral and tetrahedral sites relative to the standard basis of $R_3$ of a Unit Cell

Reasons for [crystallography]:

• There is a large amount of current mathematics devoted to crystallography ranging from inverse scattering, X-ray/Radon transforms, and especially the study of the phase problem
• The geometry of unit cells of crystal lattices is mathematical (the tiling problem in 3D).
• It is a somewhat special field at the intersection of group theory, linear algebra, Fourier analysis, and analytic geometry (perhaps more?)

Reasons against [crystallography]:

• It is a somewhat specialised field, and we may not get much call for questions of that sort here.
• Questions that would fall under this tag could in principal be tagged as a combination of other tags. (The question linked above could perhaps have the [tiling] and [analytic-geometry] tags added.)

Thoughts?

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No. We don't need it. –  Asaf Karagila Nov 12 '12 at 9:58
Maybe not yet; geometry would cover the question in, uhurm, question for the time being (and didn't we once have a lattices tag?). If we are suddenly awash in crystallographic questions, then I suppose we can reconsider... –  Ｊ. Ｍ. Nov 12 '12 at 11:23
Special in the sense of specialized, I presume. –  Did Nov 12 '12 at 11:49
@J.M. That tag was split into lattice-orders and integer-lattices. See meta and chat –  Martin Sleziak Nov 12 '12 at 13:00
@did: yes. I edited to reflect that. –  Willie Wong Nov 12 '12 at 13:13
@J.M.: as Martin indicated, the lattices tag was split. And unfortunately neither of them works well for this context. (I guess if we stretch it a bit, integer-lattices can be okay, but it is not ideal.) –  Willie Wong Nov 12 '12 at 13:15