Structure and dynamics of graphite intercalation compounds. Part 1.—Neutron diffraction and the structure of C8K, C8KH⅔ and C8KD⅔

Abstract

The neutron diffraction patterns from C₈K, C₈KD_⅔ and C₈KH_⅔ have been measured at 300 K using samples prepared from a large variety of different graphites. The effect of sample texture on the degree of order that can be produced in the intercalation compounds is reported.

A difference synthesis is made for the diffraction patterns of C₈KD_⅔ and C₈KH_⅔ and locates the hydrogen species in the median plane between the graphite sheets and potassium layers, confirming recent models. A model structure is fitted to the powder diffraction data and leads to a three-dimensional arrangement for a hydride ion species in the intercalated region of C₈KH_⅔ materials.