Configuration of the Water Molecule in Cupric Fluoride Dihydrate at 298°K

Abstract

The crystal structure of cupric fluoride dihydrate at 298°K has been redetermined from three‐dimensional, single crystal,neutron diffraction data. Least‐squares refinement of 163 independent, observed reflections gave a final, weighted R index Rw = 0.038. The H – O – H angle in the water molecule is 110.6° ± 0.2° , which, in contrast to the value 115.5° ± 0.4° found in an earlier study, is not significantly different from the tetrahedral angle of 109.5°. Thermal vibration is highly anisotropic, with much larger amplitudes perpendicular to infinite, hydrogen‐bonded sheets than parallel to the sheets.