Cation substitutional chemistry in the r(7)x(12)z-type structure for four lanthanum iodide examples

A series of quaternary lanthanide halide cluster compounds ALa(6)I(12)Z with transition metal interstitials (principally Os) and alkali or alkaline-earth metal cations (A = Na, Mg, Ca, Sr) have been synthesized by high temperature solid state techniques. The compounds were structurally characterized by single crystal and powder X-ray diffraction methods. The new compounds are isotypic (R3, Z = 3) with rhombohedral R(7)X(12)Z (R = Sc, Y, La-Lu; X = Cl, Br, I; Z = transition or main group element) and contain nominally octahedral R(6)X(12) units centered by interstitial Z. Here, the cation (A) rather than the seventh R occupies the isolated position between clusters along c as A(x)R(1-x) with 0 < x