ChemInform Abstract: Crystal Chemistry of the New Families of Interstitial Compounds R₆Mg₂₃C (R: La, Ce, Pr, Nd, Sm, or Gd) and Ce₆Mg₂₃Z (Z: C, Si, Ge, Sn, Pb, P, As, or Sb).

Abstract

Crystal Chemistry of the New Families of Interstitial Compounds R 6Mg23C (R: La, Ce, Pr, Nd, Sm, or Gd) and Ce 6Mg23Z (Z: C, Si, Ge, Sn, Pb, P, As, or Sb).-The title compounds are prepared by melting mixtures of the elements twice at 1100 C followed by annealing (Ta crucible, 700 C, 14 d). The samples are characterized by powder and single crystal XRD, and TB-LMTO-ASA electronic structure calculations. All phases crystallize with the cubic Zr 6Zn23Si-type structure (a filled variant of the Th 6Mn23 structure) in the space group Fm3m with Z = 4. The addition of a third element Z located in the octahedral cavity of the Th6Mn23 cell stabilizes this structural arrangement and enables the formation of the Ln 6Mg23Z (Ln: La, Ce, Pr, Nd, Sm, or Gd) compounds. The interstitial element forms strongly bonded [Ln 6Z] octahedral moieties spaced by zeolite cage-like [Mg 45] clusters. -(WRUBL, F.; MANFRINETTI*, P.; PANI, M.; SOLOKHA, P.; SACCONE, A.; Inorg. Chem. 55 (2016) 1, 191-204, http://dx.