Syntheses, Structures, and Magnetism of Barium/ Rare-Earth/Bismuth Double Perovskites. Crystal Structures of Ba2MBiO6 (M = Ce, Pr, Nd, Tb, Yb) by Powder Neutron Diffraction

William T.A. Harrison, Kenneth P. Reis, Allan J. Jacobson, Lynn Schneemeyer, Joseph V. Waszczak

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Abstract

The series of double perovskites Ba2MBiO6 (M = Ce to Lu) have been synthesized and characterized by chemical analysis and powder X-ray diffraction. The crystal structures of Ba2MBiO6 (M = Ce, Pr, Nd, Tb, Yb) have been determined by Rietveld analysis of powder neutron diffraction data. Magnetic susceptibility data for the compounds with M - Ce, Pr, Nd, and Tb are reported. In Ba2CeBi06, the octahedral B cations are disordered, and magnetic susceptibility data indicate that cerium is present solely as CeIV in this phase. Crystal data: Mr = 719.78, orthorhombic, Pbnm (No. 62), a = 6.2158 (3) Å,b = 6.1793 (3) Å, c = 8.7286 (4) Å,V = 335.25 (3) Å3, Z = 2, Rp = 6.92%, Rwp = 8.64%, X2 = 1.22. Ba2- PrBiO6 shows ~75% ordering of the PrIII/PrIV and BiIII/Biv cations over two sites. This phase shows temperature-independent paramagnetism. Crystal data: Mr - 718.03, monoclinic, I2/m (No. 12), a = 6.2011 (2) Å, b = 6.1583 (2) Å, c = 8.6968 (3) Å, β - 89.922 (5)°, V = 332.12 (2) Å3, Z = 2,Rp - 7.87%, Rwp = 10.04%, X2 = 1.13. Ba2NdBiO6 contains fully ordered NdIII and Biv and is paramagnetic between 4.2 and 300 K. Crystal data: Mr - 723.90, monoclinic, I2/m (No. 12), a = 6.1776 (2) Å, b = 6.1366 (2) Å, c = 8.6686 (3) Å, β = 89.801 (2)°, V = 328.62 (3) Å3, Z = 2, Rp = 3.12%, Rwp = 4.34%, X2 = 1.28. Paramagnetic Ba2- TbBiO6 contains a mixture of TbIII and TbIV at the terbium site and BiIII and Biv at the bismuth site. Crystal data: Mr = 738.58, monoclinic, I2/m (No. 12), a = 6.1104 (2) Å, b = 6.0813 (3) Å, c = 8.5922 (4) Å, β = 89.97 (2)°, V = 319.28 (2) Å3, Z = 2, Rp = 6.76%, Rwp = 8.53%, X2 = 1.06. Ba2YbBiO6 contains YbIII on one octahedral site and Biv on the other. Crystal data: Mr = 752.69, trigonal R3 (No. 148), a = 6.0252 (2) Å, α = 60.037 (2)°, V = 154.797 (1) Å3, Z=1,Rp = 4.71%, Rwp = 5.90%, X2 = 1.87.

Original languageEnglish
Pages (from-to)2161-2167
Number of pages7
JournalChemistry of Materials
Volume7
Issue number11
DOIs
StatePublished - 1 Jan 1995

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