Copper I 7400 Synthesis and Crystal Structure of Sodium Copper Tetrametaphosphimate Heptahydrate Na 2 Cu(PO 2 NH) 4 ·7H 2 O and Sodium Potassium Copper Tetrametaphosphimate Heptahydrate KxNa2-xCu(PO2NH)4·7H2O. -Large blue crystals of Na2Cu(PO2NH)4·7H2O and K0.47Na1.53Cu(PO2NH)4·7H2O are prepared in sodium silicate gels from aqueous solutions of Cu(NO3) and β-Na4(PO2)4 or K4(PO2NH)4. The crystal structures are determined by single crystal XRD. The compounds crystallize isotypically in the orthorhombic space group Pnma with Z = 4. The P 4 N 4 rings of the tetrametaphosphimate anion exhibit a distorted chair-2 conformation with admixtures of saddle and crown conformation. The compounds form a three-dimensional network structure with channels along [100] and [010]. -(ROEMER, S. R.; SCHNICK*, W.; Solid State Sci. 9 (2007) 7, 644-652; Lehrstuhl Anorg. Festkoerperchem.,

4-ions and water molecules. The P4N4 ring of the anions exhibit a slightly distorted chair-2 conformation. The tetrametaphosphimate anions are connected to layers which are interconnected to a three-dimensional network by hydrogen bonds only.

Barium I 1500 High-Pressure Synthesis and Characterization of the Alkaline Earth Borate β-BaB 4 O 7 . -Single crystals of the new title compound are obtained from stoichiometric a mixture of BaO and B2O3 under high pressure/high temperature conditions (BN crucible, 7.5 GPa, 1100°C, 10 min). β-BaB4O7 crystallizes in the space group Pmnb with Z = 2 with a network structure formed exclusively by corner-sharing BO4 tetrahedra. The relationships of β-BaB4O7 to the ambient-pressure phase α-BaB4O7 and to the isotypic high-pressure phases β-MB 4 O 7 (M: Ca, Hg, Sn) and the ambientpressure phases MB4O7 (M: Sr, Pb, Eu) are discussed. -(KNYRIM, J. S.; ROEMER, S. R.; SCHNICK, W.; HUPPERTZ*, H.; Solid State Sci. 11 (2009) 2, 336-342; Inst. Allg. Anorg. Theor. Chem., Leopold-Franzens-Univ., A-6020 Innsbruck, Austria; Eng.) -W. Pewestorf 19-017

BeP2N4 is synthesized from Be3N2 and P3N5 (multi‐anvil apparatus, 1500 °C, 5 GPa).

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