Preparation and crystal structure of californium oxyfluoride, CfOF

Abstract

A single crystal of CfOF was prepared by hydrolysis of CfF 3 at high temperature. It was identified by comparison of X-ray diffraction data with those of lanthanide and other actinide oxyfluorides. The crystal structure was determined by single-crystal X-ray diffraction techniques, and the parameters were refined by the method of least squares. The observed, face-centered cubic structure is of the fluorite type, with oxygen and fluorine atoms randomly distributed over the anion sites. The unit cell dimension is 5·561 Å (σ = 0·004 Å), from which the Cf-(O, F) distance was calculated to lie between that predicted for the Sm-(O, F) and Eu-(O, F) distances in SmOF and EuOF. Isotropic thermal parameters, 2·6 Å 2 for Cf and 3·4 Å 2 for the average (O, F) anion, were obtained.