SFAC Instruction
SFAC elements
Element symbols which define the order of scattering factors to be employed
by the program. The first 94 elements of the periodic system are recognized.
The element name may be preceded by '$' but this is not obligatory (the '$'
character is allowed for logical consistency but is ignored). The program uses
the neutral atom scattering factors, f' and f" and absorption coefficients
from International Tables for Crystallography, Volume C (1992), Ed. A.J.C.
Wilson, Kluwer Academic Publishers, Dordrecht: Tables 6.1.1.4 (pp. 500-502),
4.2.6.8 (pp. 219-222) and 4.2.4.2 (pp. 193-199) respectively. The covalent
radii stored in the program are based on experience rather than taken from a
specific source, and are deliberately overestimated for elements which tend to
have variable coordination numbers so that 'bonds' are not missed, at the cost
of generating the occasional 'non-bond'. The default radii (not those set for
individual atoms by CONN) are printed before the connectivity table.