Notizen: Sodium Metaperrhenate, NaReO4: High Pressure Synthesis of Single Crystals and Structure Refinement

Single crystals of sodium metaperrhenate, NaReO , have been obtained by oxidation of rhenium metal with sodium nitrate under high pressure- high temperature conditions (modified Belttype apparatus, 4 kbar, 400 °C, Au-capsules). The crystals are tetragonal, space group I4 /a, with a = 5.3654(4), c = 11.732(2) Å and Z = 4. The structure was refined to R - 0.026, R = 0.013 for 382 unique, absorption-corrected reflections. The scheelite-type structure for NaReO , proposed by Beintema in 1937, could be confirmed. It consists of isolated ReO tetrahedra (Re-O= 1.728(2) Å ), connected by NaOs dodecahedra ( = 2.582(2) Å).