              The [2][2] element of the 3x3 matrix used to transform\
               fractional coordinates in the ATOM_SITE category to Cartesian\
               coordinates in the same category. The axial alignments of this\
               transformation are described in _atom_sites.Cartn_transform_axes.\
               The 3x1 translation is defined in\
               _atom_sites.Cartn_transf_vector[].\
\
               |x'|              |11 12 13| |x|               |1|\
               |y'|~Cartesian~ = |21 22 23| |y|~fractional~ + |2|\
               |z'|              |31 32 33| |z|               |3|