crystal_family: Crystal family corresponding to given space group.
Description
Crystal family corresponding to given space group.
Usage
crystal_family(gn)
Value
A character string, the name of the crystal family associated
with the given space group. If the input integer does not correspond
any existing space group, the function returns NULL and throws a
warning.
Arguments
gn
A natural integer (1,2,3,...). the space group number.