A prefix to specify
configuration
(absolute or relative) or
conformation
. For example
R, S
;
r, s
;
P, M
;
Re, Si
;
E, Z
;
ap, sp
; etc.
Source: PAC, 1996,
68, 2193. (
Basic terminology of stereochemistry (IUPAC Recommendations 1996)) on page 2218 [
Terms] [
Paper]