Stucture Determination of the Monoclinic Form of KCN

The crystal structure of the monoclinic form in the metastable phase of KCN was analyzed by X-ray diffraction method. It was found that the structure is A-base-centered monoclinic with space group A 2/ m . The K + ions lie on the A -base-centered sheets, the C or N atoms occupy statistically on the eight equivalent positions (8j) which give a two-dimensional orientational disorder of CN - ion of which shape is of cross. The center of mass positions of the CN - ions are (0.5, 0.5, 0.0) and (0.5, 0.0, 0.5) of the monoclinic cell and lie on the {100} planes of the original cubic lattice.