Neutron diffraction study of LaNi₄Co and LaNi₄CoD₄

Abstract

The compound LaNi4Co is isostructural with LaNi5. The distribution of the Co atoms in the 2c and 3g special positions of the space group D6h1-P6/mmm is not random. Deuterisation yields LaNi4CoD4 with structure that belongs to the orthorhombic space group D2h19-Cmmm. The deuterium atoms occupy the 4e and 4h special position of this symmetry. The reduced deuterium content in LaNi4CoD4 as compared with that in LaNi5D6 is consistent with geometrical considerations and the different symmetries.