Gondek, L.; Kozlak, K.; Czub, J.; Rusinek, D.; Szytula, A.; Hoser, A.: On the verge of short D-D distances in RNiIn deuterides. Intermetallics 34 (2013), p. 23-28

The paper reports the peculiar structural behavior of RNiIn deuterides. The RNiIn compounds with (R = La, Ce, Pr, Nd) are known as exhibiting unusually short H-H (D-D) interatomic distances of about L6 angstrom (two hydrogen atoms within the R3Ni2 polyhedron). In our paper, the synthesis procedure and structural data for RNiIn deuterides with R = La, Nd, Cd, Tb, Dy, Ho, Er are presented for the first time. The analysis of the collected data revealed that short D-D distances are present only for R = La-Nd. For samples with heavy rare earths, the deuterium content remains nearly the same, although the D atoms occupy different coordination polyhedra. Therefore, an existence of a strict limit for the height of R3Ni2 polyhedron, for which double hydrogen occupation is possible, should be issued. High-temperature Xray diffraction experiments were performed for chosen deuterides as well. (C) 2012 Elsevier Ltd. All rights reserved.