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Abstract

A new chromium tellurite oxochloride, Cr3Te5O13Cl3, has been prepared by solid-state reaction and the crystal structure was determined by single crystal X-ray diffraction. The compound crystallizes in the non-centrosymmetric space group P2(1)2(1)2(1) with the unit cell a = 4.90180(10) angstrom, b = 17.3394(2) angstrom, c = 17.5405(2) angstrom, Z = 4, R-1 = 0.0282. The Cr3+ ions have octahedral [CrO6] oxygen coordination, the Te4+ ions have one sided [TeO3] and [TeO3Cl] coordinations. The [CrO6] octahedra are edge sharing and form chains extending along [100]. These are connected by corner sharing [TeO3] and [TeO3Cl] groups to form layers parallel to (110). The layers are connected by weak interactions in between Te4+ in the layers and Cl- ions located in between. The compound undergoes antiferromagnetic ordering at similar to 34 K with a Weiss constant of -230 K. Isothermal magnetization measurements reveal a critical field of about 0.25 T above which the magnetization versus field changes from linear to a Brillouin-like saturation behaviour. The frustration ratio amounts to similar to 6.8 indicative of sizable competing antiferromagnetic spin-exchange interaction. The dielectric constant epsilon (6 kHz) amounts to similar to 7.9 and decreases by about 1% on cooling from 50 K to liquid helium temperatures.