Layered calcium hydrogen selenite chlorides Ca(HSeO 3 )Cl and Ca(HSeO 3 )Cl(H 2 O), the first halides obtained in СaCl 2 –H 2 SeO 3 –H 2 O system
Résumé
Abstract Synthesis, crystal structures and IR spectra of the first representatives of calcium hydrogen selenite halides are reported. Colourless prismatic crystals of calcium hydrogen selenite chloride Ca(HSeO 3 )Cl and corresponding hydrated analogue Ca(HSeO 3 )Cl(H 2 O) were produced upon evaporation of aqueous solutions. Ca(HSeO 3 )Cl is monoclinic, P 2 1 / c , a = 7.0031(11) Å, b = 7.7336(12) Å, c = 8.5024(13) Å, β = 109.889(3)°, V = 433.02(12) Å 3 , R 1 = 0.039. Ca(HSeO 3 )Cl(H 2 O) is orthorhombic, Pbca , a = 6.222(4) Å, b = 10.413(7) Å, c = 16.875(10) Å, V = 1093.3 (12) Å 3 , R 1 = 0.041. Ca(HSeO 3 )Cl and Ca(HSeO 3 )Cl(H 2 O) represent new structure types. In both structures, Ca 2+ cations adopt mixed-ligand environments formed by oxygen atoms of hydrogen selenite anions (and water molecules for Ca(HSeO 3 )Cl(H 2 O)) and chloride ions. Both structures are layered. The crystal structure of Ca(HSeO 3 )Cl(H 2 O) demonstrates a rare phenomenon of hydrogen-bonded assembly of water and chloride in the interlayer space.