Crystallographic study of LaNi5-xSnx (0.2≤x≤0.5) compounds and their hydrides

The structural properties of tin substituted LaNi5 compounds and corresponding deuterides have been investigated by single crystal X-ray and neutron powder diffraction. Tin is found to substitute nickel exclusively on site 3g of space group P6/mmm. No other significant disorder occurs in the structure. At tin contents of x=0.4 and x=0.5, the crystal structures of the deuterides do not significantly deviate from those of other metal substituted LaNi5 deuterides. At a tin content of x=0.2, with higher deuterium content, however, a symmetry decrease to non-centrosymmetric space group P6mm is observed due to partial deuterium ordering. (C) 1999 Elsevier Science S.A. All rights reserved.