Crystal structures of the trifluoromethyl sulfonates M(SO₃CF₃)₂ (M = Mg, Ca, Ba, Zn, Cu) from synchrotron X-ray powder diffraction data

The crystal structures of divalent metal salts of trifluoromethyl sulfonic acid ("trifluoromethyl sulfonates") M(SO(3)CF(3))(2) (M = Mg, Ca, Ba, Zn, Cu) were determined from high-resolution X-ray powder diffraction data. Magnesium, calcium and zinc trifluoromethyl sulfonate crystallize in the rhombohedral space group R(bar)3. Barium trifluoromethyl sulfonate crystallizes in the monoclinic space group I2/a(C2/c) and copper trifluoromethyl sulfonate crystallizes in the triclinic group P(bar)1. Within the crystal structures the trifluoromethyl sulfonate anions are arranged in double layers with the apolar CF(3) groups pointing towards each other. The cations are located next to the SO(3) groups. The symmetry relations between the different crystal structures have been analysed.