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A series of lanthanide containing mixed-valent vanadium (III/IV) silicates of the type Ca x Ln 1−x VSiO 5 ( Ln = Ce–Nd, Sm–Lu, Y) was synthesized as high quality single crystals from a molten chloride eutectic flux, BaCl 2 /NaCl. Utilizing Ca metal as the reducing agent, an in-situ reduction of V 5+ to V 3+/4+ as well as of Ce 4+ to Ce 3+ was achieved. The structures of 14 reported isostructural compounds were determined by single crystal X-ray diffraction. They crystallize in the tilasite (CaMgAsO 4 F) structure type in the monoclinic space group C 2 /c . The extended structure contains 1D chains of VO 6 octahedra that are connected to each other via SiO 4 groups and (Ca/ Ln )O 7 polyhedra. The magnetic susceptibility and the field dependent magnetization data were measured for Ca x Ln 1−x VSiO 5 ( Ln = Ce–Nd, Sm, Gd–Lu, Y), and support the existence of antiferromagnetic behavior at low temperatures. [ABSTRACT FROM AUTHOR]

Single crystals of mixed valent barium titanium(III/IV) chlorosilicate, Ba 3 Ti 2 Si 4 O 14 Cl 0.91 O 0.09 , were grown in a high temperature molten chloride flux involving an in situ reduction step. The fresnoite structure related Ba 3 Ti 2 Si 4 O 14 Cl 0.91 O 0.09 crystallizes in the tetragonal space group P 4/ mbm with lattice parameters of a =8.6717(2) Å, c =18.6492(5) Å. The title compound exhibits a 3D structure consisting of 2D layers of fused Ti 2 O 9 and Si 4 O 12 groups and 2D layers of fused Ti 2 O 9 Cl 2 and Si 2 O 7 groups that are linked via barium atoms. The in situ reduction of Ti(IV) to Ti(III) is achieved via the addition of metallic Mg to the flux to function as the reducing agent. The temperature dependence of the magnetic susceptibility shows simple paramagnetism above 100 K. There is a discontinuity in the susceptibility data below 100 K, which might be due to a structural change that takes place resulting in charge ordering. [ABSTRACT FROM AUTHOR]

The new oxytelluride Ba3Yb2O5Te was obtained from an alkaline earth flux. Ba3Yb2O5Te crystallizes in the tetragonal space group P4/mmm (#123), with a=4.3615(3)Å and c=11.7596(11)Å, Z=1. The structure combines two distinct building blocks, a Ba2Yb2O5 perovskite-like double layer with square bipyramidal coordination of the ytterbium ions, and a CsCl-type BaTe layer. Short range magnetic order is apparent at below 5K, with the magnetic behavior above this temperature dominated by crystal field effects. The structure may be considered as an analog to the Ruddlesden–Popper phases, where the NaCl-type layer has been replaced by the CsCl-type layer. The two-dimensional magnetic behavior is expected based on the highly anisotropic nature of the structure. [ABSTRACT FROM AUTHOR]

Abstract: The reactions of UO3 and TeO3 with KCl, RbCl, or CsCl at 800°C for 5d yield single crystals of A2[(UO2)3(TeO3)2O2] (A=K (1), Rb (2), and Cs (3)). These compounds are isostructural with one another, and their structures consist of two-dimensional sheets arranged in a stair-like topology separated by alkali metal cations. These sheets are comprised of zigzagging uranium(VI) oxide chains bridged by corner-sharing trigonal pyramidal TeO32- anions. The chains are composed of dimeric, edge-sharing, pentagonal bipyramidal UO7 moieties joined by edge-sharing tetragonal bipyramidal UO6 units. The lone-pair of electrons from the TeO3 groups are oriented in opposite directions with respect to one another on each side of the sheets rendering each individual sheet non-polar. The alkali metal cations form contacts with nearby tellurite oxygen atoms as well as with oxygen atoms from the uranyl moieties. Crystallographic data (193K, MoKα, ): 1, triclinic, space group , , , , , , , , , for 98 parameters and 1697 reflections with ; 2, triclinic, space group , , , , , , , , , for 98 parameters and 1817 reflections with ; 3, triclinic, space group , , , , , , , , , for 98 parameters and 1965 reflections with . [Copyright &y& Elsevier]