Neutron powder diffraction study on highly deuterated Ca(IO3)2.D2O

Neutron powder diffraction experiments were performed on highly deuterated calcium iodate monohydrate (bruggenite) to examine possible H/D enrichment effects. The title compound is built up of distorded CaO 8 quadratic antiprisms. The iodate ions form layers parallel to (100), revealing relativity short interionic I...O distances of 3.02 and 2.90 A. The water molecules are trigonally planar coordinated (2 IO - 3 , 1 Ca 2+ , site symmetry C 1 ), forming asymmetric hydrogen bonds of different strengths to adjacent iodate ions. Deviation from random distribution of the H atoms has been established.