Crystal structure and properties of CaO28H2O

The molecular and crystal structure of calcium peroxide octahydrate was refined using single-crystal X-ray diffraction. Compound CaO 2 . BH 2 O crystallizes in a tetragonal unit cell with the parameters a = 6.197(1) A, c =10.967(2) A, space group P4/mcc, Z = 2. The water hydrogen atoms are located objectively. A model is proposed to explain the formation of a hydrogen-bond network that links complex cations [Ca(H 2 O) 8 ] 2 + and anions [O 2 ] 2 - to a three-dimensional structure. The hydrogen-bond network suggests that a cooperative proton transfer appears in the crystal. CaO 2 . BH 2 O single crystals were studied by vibrational spectroscopy to gain more information about the structure of the hydrogen-bond network. The nature of proton conductivity in the compound is discussed.