RS See racemate . S. Sawhorse Projection A perspective formula indicating the spatial arrangement of bonds on two adjacent carbon atoms. In general a Newman or zig-zag projection is preferred. See also primary structure , tertiary structure , quaternary structure . Si See Re, Si.
Sequence Rules See priority .
Skew See torsion angle and chair, boat, twist. Space Formula Synonym for stereochemical formula. Spontaneous Resolution See racemic conglomerate . SR See racemate . The conformation of groups attached to two adjacent atoms is said to be staggered if the torsion angles are such that the groups are as far away as possible from an eclipsed arrangement.