Thermal decomposition of cesium azide (CsN 3 ) leaves elemental cesium behind, which was in-situ produced and used for the syntheses of the two new cesium thiotellurates Cs 2 [TeS 2 ] and Cs 2 [TeS 3 ] along with appropriate amounts of tellurium and sulfur. The first compound crystallizes orthorhombically in space group Cmc2 1 with the lattice parameters a = 783.39(4), b = 1126.72(8), c = 823.04(5) pm (Z = 4) and the second one monoclinically in space group P2 1 /n with the lattice parameters a = 997.12 (6), b = 1269.71(8), c = 1410.23(9) pm, β = 91.218(3)°(Z = 8). While ψ 1 -tetrahedral complex thiotellurate(IV) anions [TeS 3 ] 2are found as pyramids in * Prof. Dr. Th. Schleid 2875 Cs 2 [TeS 3 ], Cs 2 [TeS 2 ] comprises ψ 2 -tetrahedral thiotellurate(II) units [TeS 2 ] 2as boomerangs and both occur isolated in the corresponding structures. In each of the title compounds, the anionic part of the structures is arranged layer-like with Cs + cations sitting in between the layers. The cesium cations in the sulfur-rich compound Cs 2 [TeS 3 ] exhibit coordination numbers of seven and eight, while in the Cs 2 [TeS 2 ] these cations are surrounded by only six sulfide anions. But even the lone-pair electrons at the central Te 4+ and Te 2+ cations help to complete the Cs + coordination spheres in both cases.
We report for the first time on superconductivity achieved upon hole doping when Ca 2+ is partially substituted with Na + in CaFFeAs. Single crystals of Ca 0.89 Na 0.11 FFeAs up to 2 × 2 mm 2 in size with T c = 34.5 K were grown from NaCl flux. The superconducting transition temperature, with a narrow width ∼2 K, confirmed by both magnetic and resistivity measurements, indicates the high quality of our samples. Magnetic relaxation measurements show that the flux creep in this material is larger than in other iron-based superconductors. The existence of the wide magnetic reversible region and the pronounced flux-creep effect can be attributed to the higher anisotropy of this material.
A series of polycrystalline double perovskites SrLaBIrO 6 (B = Ni, Mg, Zn) containing Ir 5+ (5d 4 ) was synthesized by solid state reactions, and structural, magnetic and electronic properties were investigated. The isotypic fully ordered double perovskites crystallize in space group P2 1 /n and show semiconducting behavior with estimated bandgaps of approximately 0.2 eV for SrLaNiIrO 6 and SrLaZnIrO 6 , 2095 and 0.4 eV for SrLaMgIrO 6 . SrLaNiIrO 6 is an antiferromagnet with a Néel temperature of 74 K (μ eff = 3.3 μ B , θ W = -90 K), whereas SrLaMgIrO 6 and SrLaZnIrO 6 are weakly paramagnetic. All title compounds exhibit a temperature-independent contribution to the measured magnetic susceptibility, which supports the notion for a van-Vlecktype response originating from the Ir 5+ (5d 4 , J eff = 0) ions.
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