The synthesis and the crystal structure of two new intermetallic phases with formula Ca5Rh and Ca5Ir are reported. The two compounds are isotypic and crystallize with a new structure type. The crystal structure, elucidated by single-crystal X-ray techniques for the iridium compound and confirmed for Ca5Rh by powder data, is orthorhombic, oP24-Pnma, Z = 4. The lattice constants, as obtained from Guinier powder patterns are: a = 7.655(3) angstrom, b = 15.878(6) angstrom and c = 6.786(2) angstrom for Ca5Ir and a = 7.569(3) angstrom, b = 16.067(10) angstrom and c = 6.725(3) angstrom for Ca5Rh. Apart for the 9:1 phase found in several M-X systems (M = Ca, Sr, Eu; X = Rh, Ir, Pd, Pt), whose structure, however, has not yet been solved, the 5:1 composition represents the M-richest composition so far observed in such systems. (C) 2006 Elsevier B.V. All rights reserved.
Ca5Rh and Ca5Ir: Isotypic compounds with a new structure type
2007
Abstract
The synthesis and the crystal structure of two new intermetallic phases with formula Ca5Rh and Ca5Ir are reported. The two compounds are isotypic and crystallize with a new structure type. The crystal structure, elucidated by single-crystal X-ray techniques for the iridium compound and confirmed for Ca5Rh by powder data, is orthorhombic, oP24-Pnma, Z = 4. The lattice constants, as obtained from Guinier powder patterns are: a = 7.655(3) angstrom, b = 15.878(6) angstrom and c = 6.786(2) angstrom for Ca5Ir and a = 7.569(3) angstrom, b = 16.067(10) angstrom and c = 6.725(3) angstrom for Ca5Rh. Apart for the 9:1 phase found in several M-X systems (M = Ca, Sr, Eu; X = Rh, Ir, Pd, Pt), whose structure, however, has not yet been solved, the 5:1 composition represents the M-richest composition so far observed in such systems. (C) 2006 Elsevier B.V. All rights reserved.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
