Structure of phosphonium rhenates(VII)

Four phosphonium rhenates(VII) were prepared and crystallized: (A) 1,2-bis (triphenylphosphonium)ethane rhenate(VII) (Pī, a=8.298(2), b=10.638(3), c= 11.242(3) ?, α=64.96(2), β=80.49(2), γ=88.17(2)°), (B) methyltriphenylphosphonium rhenate(VII) (Pca2₁, a=15.096(3), b=12.627(3), c=19.353(3) ?), (C) benzyltriphenylphosphonium rhenate(VII) (Pī, a=9.648(2), b=11.689(2), c=20.806(3) ?, α=88.44(2), β=84.63(2), γ=77.33(3)°), and (D) orthorhombic form of (iodomethyl)triphenylphosphonium rhenate(VII) (Pca2₁, a=14.952(3), b=13.120(3), c=20.603(4) ?). Each crystal structure consists of separate phosphonium cations and rhenate(VII) anions. In A centrosymmetric 1,2-bis(triphenylphosphonium)ethane cations form layers perpendicular to [011]. In B the cations are set in chains along [100] forming layers perpendicular to [001]. In C two symmetrically-independent cations form double columns along [100] and these columns are arranged in puckered layers perpendicular to [001]. D is almost isomorphous to B. The crystal structures are stabilised by weak C–H⋯O hydrogen bonds as well as phenyl rings interactions. In all crystal structures supramolecular motifs of phenyl rings embraces could be distinguished.     

电感耦合等离子体原子发射光谱法测定高纯铼酸铵中Ca、Cd、Mn、Fe、Mg、Al、Cu、Co、Mo、Pb、Sn和Ni

本文介绍了电感耦合等离子体发射光谱法（ICP－AES）测定高纯铼酸铵中12个杂质元素的方法。采用挥发健康基体，探讨了高铼酸铵基体的干扰及其消除办法。ICP－AES测定结果的准确度和精密度均能满足分析要求。     

Structural investigation of Sr2LiReO6. Evidence for a continuous tetragonal-cubic phase transition

The presence of a continuous and reversible -I4/m phase transition in a polycrystalline sample of the ordered double perovskite Sr₂LiReO₆ is described. The transition that occurs near 300 °C is a consequence of in-phase tilting of the BO₆ octahedra. The temperature dependence of both the lattice parameters and the spontaneous strains are consistent with a second order phase transition as would be expected for a soft mode transition.