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New compounds Ag 5 Se(PO 4 ) and Ag 5 Te(PO 4 ) have been synthesized as black air-stable polycrystalline powders, and their structures determined from X-ray powder diffraction data. The two new compounds are isostructural and crystallize in the space group P4/nmm (No. 129) with the unit cell parameters a ϭ 6.8886(5), c ϭ 7.2724(7) Å , Z ϭ 2 and a ϭ 7.0098(5), c ϭ 7.3423(7) Å , Z ϭ 2, respectively. Their crystal structures comprise a positively charged silverϪchalcogen framework and separate tetrahedral PO 4 3Ϫ ions.

Tetrasilver telluride sulfate was obtained as a black air‐stable polycrystalline powder; its structure was determined from X‐ray powder diffraction data. The new compound crystallizes in the cubic space group P213, with the unit cell parameter a = 8.6263(2) Å and Z = 4. The crystal structure of Ag4Te(SO4) is composed of a positively charged silver‐telluride three‐dimensional framework, in which the isolated tetrahedral SO42– anions are embedded. The framework features an irregular coordination for tellurium atoms with a coordination number of six and manifold Ag–Ag contacts ranging from 2.99 to 3.14 Å. The distortion of the SO42– anion as well as the interactions within the framework and between the framework and the SO42– anions are analyzed with the help of the structural data, vibrational spectra, and band structure calculations.

Framework. -The title compound is prepared by solid state reaction of an equimolar mixture of Ag2Te and Ag2SO4 (sealed tube, 1. 823 K, 6 d; 2. 573 K, 8 d). Ag4Te(SO4) crystallizes in the cubic space group P213 with Z = 4 (powder XRD). The structure consists of a three-dimensional [Ag4Te 2+ ] framework with embedded anions. -(SHESTIMEROVA, T. A.; MITIAEV, A. S.; DAVLIATSHIN, D. I.; SHEVELKOV*, A.

Silver I 7500Trapping Phosphate Anions Inside the [Ag4I] 3+ Framework: Structure, Bonding, and Properties of Ag 4 I(PO 4 ). -Single crystals of the title compound are grown from an equimolar mixture of Ag3PO4 and AgI at 875 K (vacuum-sealed silica tube, 5 d). Ag4I(PO4) crystallizes in the monoclinic space group P21/m with Z = 4. The three-dimensional [Ag4I] 3+ framework hosting the tetrahedral guest anions is fully ordered. The framework features high coordination numbers for iodine and various Ag-Ag bonds ranging from 3.0 to 3.4 Å. The Ag-Ag interaction is bonding and involves silver 4d and 5s orbitals lying, together with the orbitals of iodine, just below the Fermi level. Pure Ag4I(PO4) is a poor conductor with a room temperature conductivity of 3·10 -6 S/m. The discrepancies between the properties observed in this work and those reported previously are discussed. -(OLENEVA, O. S.; KIRSANOVA, M. A.; SHESTIMEROVA, T. A.; ABRAMCHUK, N. S.; DAVLIATSHIN, D. I.; BYKOV, M. A.; DIKAREV, E. V.; SHEVELKOV*, A. V.; J. Solid State Chem. 181 (2008) 1, 37-44; Lomonosov Moscow State Univ., Moscow 119899, Russia; Eng.) -Schramke 15-021 PO 3-4