Two new layered oxohalides in the system Cu–Yb–Te–O–Cl

Abstract

Two complex lanthanide(III) transition metal(II) tellurium(IV) oxyhalides, Cu 3Yb 2(TeO 3) 4Cl 4 and Cu 3Yb 3(TeO 3) 4Cl 6 have been synthesized and the crystal structures were determined by single-crystal X-ray diffraction. Both compounds are layered with only weak connections in between the layers. The layers are made up of [YbO 8], [TeO 3] and [CuO xCl y] polyhedra. In both compounds the strong Lewis acid cations Yb 3+ and Te 4+ only form bonds to oxygen while Cu 2+ form bonds to both oxygen and chlorine. This leads the Cl − ions to be expelled from the bonding volumes of the crystal structures and protrude from the layers. Magnetic susceptibility measurements were performed on a powder sample of Cu 3Yb 2(TeO 3) 4Cl 4. The Curie–Weiss law found at low temperatures indicates a Curie–Weiss temperature of ca. −5(1) K. However, indication for long-range magnetic ordering could not be observed down to 1.87 K. The two new phases are to the best of our knowledge the first containing all three of Cu, Yb and Te.