Abstract
The paraelectric phase of copper formate tetrahydrate has been refined from three dimensional neutron diffraction data.s The occupancies reveal an approximately 2:1 ratio of two structures with screw axes 21. The precision of the occupancy determination was limited by parameter correlation.In the disordered water layers, the average O-O hydrogen bond distance is 2.78 ± 0.05 A. The average O-H distance omitting the least (0.15) occupied site is 0.98 ± 0.03 A. The amplitudes of motion for the hydrogen atoms are higher perpendicular than parallel to the bond. The nearest neighbors of the water oxygen atoms form distorted tetrahedra. The final agreement factor, R = 0.023.