The Molecular Structures of Lithium Trichlate, Li[Cl₃CSO₃]⋅2H₂O, and Lithium Tribrate, Li[Br₃CSO₃]⋅2H₂O

Lithium trichlate, Li[Cl 3 CSO 3 ] ⋅ 2H 2 O (triclinic, , Z =2, a =630.29(3) pm, b =630.65(3) pm, c =1246.10(6) pm, α =100.657(2)°, β =97.813(2)°, γ =107.994(2)°) was obtained from the reaction of (H 5 O 2 )[Cl 3 CSO 3 ] and LiOH in aqueous solution. Similarly, colourless single crystals of the tribrate Li[Br 3 CSO 3 ] ⋅ 2H 2 O (triclinic, , Z =4, a =634.65(4) pm, b =636.83(4) pm, c =2496.8(2) pm, α =83.518°, β =86.081(5)°, γ =72.061(5)°) form in the reaction of aqueous Br 3 CSO 3 H and LiOH. The acid (H 5 O 2 )[Cl 3 CSO 3 ] was obtained from the chlorination of CS 2 , followed by oxidation of the intermediate Cl 3 CSCl with H 2 O 2 . The bromo derivative Br 3 CSO 3 H has been prepared by bromination of phenylsulfonate with KOBr and subsequent ion exchange of the obtained potassium salt. Both lithium compounds exhibit molecular dimers according to {Li 2 (X 3 CSO 3 ) 2/1 (H 2 O) 2/1 (H 2 O) 2/2 } with the Li + ions in tetrahedral coordination of oxygen atoms. The difference in the crystal structures result from the variation of the orientation of the dimers with respect to each other. The experimental findings for the dimers are in good agreement with DFT calculations.