Z. Zak et al., STRUCTURES OF BIS(FLUOROSULFONYL)IMIDE HN(SO2F)(2), BIS(TRIFLUOROMETHYLSULFONYL)IMIDE HN(SO2CF3)(2), AND THEIR POTASSIUM-SALTS AT 150 K, Zeitschrift fur Kristallographie, 213(4), 1998, pp. 217-222
The structures of HN(SO2R)(2), R=E CF3 are formed by molecules linked
by hydrogen bonds to infinite chains. While KN(SO2F)(2) is composed of
alternating cations and anions, HN(SO2CF3)(2) exhibits a pronounced l
ayer structure. In the acids, the substituents -R are in trans configu
ration being on the opposite sides of the plane defined by S-N-S bonds
but in the salts the cis configuration with both substituents on the
same side of the S-N-S plane is preferred, probably due to numerous me
tal-anion interactions.