Neutron powder diffraction and solid-state deuterium NMR studies of Ca2RuD6 and the stability of transition metal hexahydride salts

The crystal structure of Ca2RuD6 has been determined by neutron powder diffraction: space group Fm3m, K2PtCl6 Structure, as found for other hexahydride salts of group 8 metals with alkaline earth or lanthanide counter ions. No structural phase transition was observed between 340 K and 50 K. The deuterium nuclear quadrupole coupling constant, 54.7 kHz, leads to an ionic character of the Ru-D bond of 76%. The known trends in the behaviour of A(2)MH(6) salts are interpreted in terms of the ionization energies of the cation and the central metal atom. (C) 2007 Elsevier B.V. All rights reserved.