Growth, single-crystal structure, and magnetic properties of the double molybdate KYb(MoO4)2

Abstract

Crystals of the rare earth double molybdate KYb(MoO 4 ) 2 were grown by spontaneous nucleation from a K 2 Mo 4 O 13 flux. The typical crystals were colorless and elongated, welldeveloped plates. The material has been characterized by powder X-ray diffraction (PXRD), energy-dispersive X-ray spectrometry (EDS), and Raman spectroscopy methods. The structural properties have been investigated through single-crystal X-ray diffraction at room temperature. KYb(MoO 4 ) 2 crystallizes in the orthorhombic symmetry, space group Pbcn (No. 60), a = 5.0395(2), b = 18.2821(9), c = 7.8635(4) Å, and Z = 4. A complete ordering of the Yb 3+ and Mo 6+ cations has been found. The Yb 3+ ions are located in distorted YbO 8 antiprisms which form chains of edge-sharing, aligned along the c-axis while the Mo 6+ ions are placed in a slightly deformed tetrahedral environment of oxygen atoms. Double bridge modes of the "Mo 2 O 8 dimers" have been identified in the unpolarized Raman spectra. The temperature-dependent magnetic susceptibility of KYb(MoO 4 ) 2 follows a Curie-Weiss law with a Weiss constant of −52 K.

Síntese por pirólise de aerossol e caracterização de molibdato de sódio e ítrio (NaY(MoO>sub<4>/sub<)>sub<2>/sub<) dopados com íons lantanídeos e estudos de conversão de energia

“…Dentre as diversas matrizes existentes, uma classe de materiais que tem sido amplamente estudada e que apresenta as características citadas acima são as matrizes à base de molibdato [19][20][21][22]. Uma matriz à base de molibidato que merece destaque é a do tipo MLn(MoO4)2 (M = metal alcalino; Ln = lantanídeos), que apresenta a estrutura do tipo scheelita [22].…”