Ethan Merritt <[log in to unmask]> writes:
> On Thursday, June 14, 2012 12:06:13 pm James Stroud wrote:
>> Hello All,
>>
>> I would like to discuss symmetry axes, but I'm not sure what the
>> notation convention is. For example, I'd like to say something about
>> a 2(1) along the x-axis, but the phrase "the 2(1) symmetry axis
>> along x" is a bit cumbersome to repeat many times or to put in a
>> table. So I'd like a shorthand, maybe something like "x(2_1)" (where
>> the preceding "_" means that the "1" is subscript. Another way I
>> like is "x_{2(1)}" (where the curly braces mean that all of "2(1)"
>> is subscript).
>>
>> Does anyone know what the convention is or if there is one?
>
> One would think that this document would have the answer:
>
> http://www.iucr.org/resources/commissions/crystallographic-nomenclature/symel
>
> But it's too cryptic for me.
>
> I'd go with the full expression in the text.
> For table entries, I'd want something shorter.
> International Tables for Crystallography, Vol A defines the glyph used to indicate
> 2_1 screws in the space group diagrams (a solid oval with two flagella).
> But finding a font to print it in your table could be challenging.
> There is a cryst.mf font for TeX if that helps.
> <http://www.tex.ac.uk/CTAN/fonts/cryst/>
This font (by Ulrich Müller) is available in many formats on the IUCr
web site:
http://www.iucr.org/resources/symmetry-font
>
> I can't find these symbols in the Unicode character tables.
> Perhaps the IUCr should propose to have Unicode code points assigned for
> the standard set of crystallographic symmetry elements.
That has occurred to me too! As far as I know, no proposal has yet been
made.
--
Ian ◎
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