Each Reciprocal Net sample record may include the space group of the structure that was analyzed. Reciprocal Net recommends that a specific space group syntax be observed by all partner labs in order to facilitate reliable searching across various labs’ collections and improve the display of space groups. Reciprocal Net recommendations are based on CIF conventions (defined by the Crystallographic Information File format specification).
It is expected that space group symbols entered by users be of the Hermann-Mauguin variety. Conformance with CIF requires that the full symbol (c.f. International Tables for Crystallography, Vol. A (1987)) be provided, and that the choice of origin be indicated if it is not implicit. The lattice type symbol and symbols referring to different axes should all be separated by spaces, screw axes should be indicated by two consecutive digits, and alphabetic symbols should be given in their conventional case (e.g. “I 41/a c d”).
Reciprocal Net site software assists users in converting nonstandard space group symbols to standard format in some instances.