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Ln: Y, La-Nd, Sm, Gd, Dy, Ho). -Single crystals of the title compounds are prepared by reaction of the rare earth metals, ZnO, and red phosphorus in a NaCl/KCl flux (1170 K, evacuated silica tube, 11-24 d). The structures of LnZnPO with Ln: Y, Sm, Gd, and Dy are determined by single crystal XRD (space group R3m, Z = 6). The structures are composed of alternate stacks of (Ln 3+ O 2-) and (Zn 2+ P 3-) layers with covalent Ln-O and Zn-P bonding within and weak ionic bonding between the layers. Susceptibility measurements on β-CeZnPO, β-PrZnPO, and GdZnPO reveal Curie--Weiss paramagnetism with experimental magnetic moments of 2.31, 3.60, and 7.72 μB/Ln atom, respectively. β-CeZnPO and β-PrZnPO show antiferromagnetic ordering with Neel temperatures of 7.4 K and 2.2 K. GdZnPO exhibits no magnetic ordering down to 2 K. Single crystal NIR/Vis absorption spectra measured for the compounds with Ln: Y, La, Pr, Nd, Sm, Dy reveal unexpected variations for the optical band gap of these phosphide oxides. For Ln: Pr, Nd, Sm, Dy, Ho f-f electronic transitions with well resolved ligand-field splittings are observed in the range 6000-20000 cm -1 . -(LINCKE, H.; GLAUM*, R.; DITTRICH, V.; TEGEL, M.; JOHRENDT, D.; HERMES, W.; MOELLER, M. H.; NILGES, T.; POETTGEN, R.; Z. Anorg. Allg.

Europium I 3400Crystal Structure, Physical Properties and HRTEM Investigation of the New Oxonitridosilicate EuSi2O2N2. -The new layered title compound is synthesized from a mixture of Eu2O3 and Si(NH)2 (1400°C, r.f. furnace, 40 h). The compound crystallizes in the triclinic space group P1 with Z = 4. Its anionic Si2O2 layers consist of corner-sharing SiON3 tetrahedra with threefold connecting nitrogen and terminal oxygen atoms. Magnetic susceptibility measurements show Curie-Weiss behavior above 20 K with an effective magnetic moment of 7.80 µB/Eu, indicating divalent europium. Luminescence measurements show a narrow emission band with regard to the four crystallographic europium sites with an emission maximum at 575 nm. -(STADLER, F.; OECKLER, O.; HOEPPE, H. A.; MOELLER, M. H.; POETTGEN, R.; MOSEL, B. D.; SCHMIDT, P.; DUPPEL, V.; SIMON, A.; SCHNICK*, W.; Chem. Eur. J. 12 (2006) 26, 6984-6990; Fachbereich Chem. Biochem.,

Lanthanoids I 2800 Structure and Optical Properties of the Arsenide Oxides LnZnAsO (Ln: Y, La-Nd, Sm, Gd-Er). -The title compounds including the new compounds HoZnAsO and ErZnAsO are prepared from 1:1:1 mixtures of the rare earth elements, As, and ZnO in a NaCl/KCl flux (silica ampules, 1120-1170 K, 6-19 d) and characterized by powder and single crystal XRD and by electronic absorption spectroscopy. The compounds crystallize in the tetragonal space group P4/nmm with Z = 2. The structures consist of alternate stacks of [LnO] + and [ZnAs]layers with covalent Ln-O and Zn-As intralayer and weak ionic interlayer bonding. The crystals are transparent with yellow (LaZnAsO) to red color tones. LaZnAsO exhibits a significantly higher optical band gap (≈2.3 eV) than LnZnAsO (Ln: Y, Pr, Nd, Sm; ≈1.9 eV). -(LINCKE, H.; GLAUM*, R.; DITTRICH, V.; MOELLER, M. H.; POETTGEN, R.; Z. Anorg. Allg. Chem. 635 (2009) 6-7, 936-941; Inst. Anorg. Anal. Chem.,

structure structure (solids and liquids) D 2000 -012The Crystal Structure of the Potential Ferroelectric Calcium Rhenate(VI, VII) Ca 11 Re 4 O 24 and Its Relation to the Structure of Sr 11 Os 4 O 24 .-The structure of the title compound, obtained by thermal decomposition of Ca 5 Re 2 O 12 in a dynamic vacuum, is determined by single crystal X-ray data (space group I4 1 , Z = 4). The Re atoms occupy two crystallographic sites, both with octahedral oxygen coordination and the Ca atoms occupy seven different sites with 8, 9, or 10 oxygen neighbors. The structure is closely related to that of Sr 11 Os 4 O 24 , which crystallizes in the centrosymmetric, monoclinic space group I2/a. It is suggested that both compounds crystallize in the common higher symmetry group I4 1 /a at higher temperatures. The title rhenate shows Curie-Weiss behavior but no superconducting transition down to 2 K. -(JEITSCHKO, W.; MONS, H. A.; RODEWALD, U. CH.; MOELLER, M. H.