Neutron Structure Analysis of Cubic CaC2 and KCN

Abstract

Neutron diffraction analysis of the cubic phase of CaC₂ has revealed the characteristics of the hindering potential for rotation of the C₂ group, i.e., the body diagonal axes being the easiest direction for the C₂ random orientation, the face diagonals being the next easiest and the cube axes being by far the hardest. A further refinement on the published neutron data of cubic KCN indicates, on the contrary to the previous analyses, a clear distinction among various orientational modes of the CN group and consequently the rotational hindering potential analogous to the CaC₂ case.