Neue Oxocuprate (I). Über Cs3Cu5O4, Rb2KCu5O4, RbK2Cu5O4 und K3Cu5O4

New Oxocuprates(I). On Cs₃Cu₅O₄, Rb₂KCu₅O₄, RbK₂Cu₅O₄ and K₃Cu₅O₄ Cs₃Cu₅O₄ light yellow, powder as well as single crystals [a = 10.313(9), b = 7.630(1), c = 14.750(4) Å, β = 106.48(6)°], Rb₂KCu₅O₄ [a = 9.724(2), b = 7.443(0), c = 14.246(2) Å, β = 106.78(8)°], RbK₂Cu₅O₄ [a = 9.561(1), b = 7.411(0), c = 14.111(1) Å, β = 106.76(7)°] and K₃Cu₅O₄ [a = 9.422(1), b = 7.364(1), c = 13.995(2) Å, β = 107.00(2)°] are new prepared. The colour of the powders becomes lighter according to the sequence showed above. K₃Cu₅O₄ shows pale yellow. The Madelung Part of Lattice Energy, MAPLE, is calculated and discussed.     

化合物Cs5EuCl8·14H2O和Cs2EuCl5·4H2O的制备和荧光性

The two new compounds Cs₅EuCl₈·14H₅O(5∶1 type) and Cs₂EuCl₅·4H₂O(2∶1 type) were found and syn-thesized from CsCl-EuCl₃-11%HCl-H₂O quaternary systems by phase equilibrium method, and were characterized and measured by ultra-violet absorption spectrometry and fluorescence spectrum. The results show that upconversion spectrum exhibit at 590nm and 610nm exited at 790nm, and the upconversion intensity increases with the EuCl₃ ratio increasing in CsCl.     

Identifying characteristics of the fibrous cesium titanate Cs2Ti5O11

Electron microscopic studies of the fibrous cesium titanate Cs₂Ti₅O₁₁ reveal characteristic features not readily apparent using standard methods of phase analysis (optical microscopy, X-ray diffraction). Its fibrous needle-like laths give characteristic diffuse scattering, complicating the indexing of electron diffraction patterns. The hydrated form Cs₂Ti₅O₁₁ · (1 + x)H₂O (0.5 < x < 1) is typically grossly distorted, resembling pyrolytic graphite. Cs₂Ti₅O₁₁ is unstable when stored under ambient conditions at room temperature for ∼1 year when disproportionation into Cs₂Ti₄O₉ and Cs₂Ti₆O₁₁ · nH₂O occurs. The structure of Cs₂Ti₅O₁₁ and intergrowth defects in the unstable forms have been studied by high-resolution electron microscopy. It is evident that these phases would be undesirable in titanate ceramics such as SYNROC, which are designed for immobilization of radioactive ¹³⁷C_s.     

Rubidium dimolybdate,Rb2Mo2O7, and caesium dimolybdate,Cs2Mo2O7

The crystal structures of dirubidium hepta­oxodimolybdate, Rb₂Mo₂O₇, and dicaesium hepta­oxodimolybdate, Cs₂Mo₂O₇, in the space groups Ama2 and P2₁/c, respectively, have been determined for the first time by single‐crystal X‐ray diffraction. The structures represent two novel structure types of monovalent ion dimolybdates, A₂Mo₂O₇ (A = alkaline elements, NH₄, Ag or Tl). In the structure of Rb₂Mo₂O₇, Mo atoms are on a twofold axis, on a mirror plane and in a general position. One of the Rb atoms lies on a twofold axis, while three others are on mirror planes. Two O atoms attached to the Mo atom on a mirror plane are located on the same plane. Rubidium dimolybdate contains a new kind of infinite Mo–O chain formed from linked MoO₄ tetra­hedra and MoO₆ octa­hedra alternating along the a axis, with two terminal MoO₄ tetra­hedra sharing corners with each octa­hedron. The chains stack in the [001] direction to form channels of an approximately square section filled by ten‐coordinate Rb ions. Seven‐ and eight‐coordinate Rb atoms are located between chains connected by a c translation. In the structure of Cs₂Mo₂O₇, all atoms are in general positions. The MoO₆ octa­hedra share opposite corners to form separate infinite chains running along the c axis and strengthened by bridging MoO₄ tetra­hedra. The same Mo–O polyhedral chain occurs in the structure of Na₂Mo₂O₇. Eight‐ to eleven‐coordinate Cs atoms fill the space between the chains. The atomic arrangement of caesium dimolybdate has an ortho­rhom­bic pseudosymmetry that suggests a possible phase transition P2₁/c→Pbca at elevated temperatures.     

Zeotype ionic crystal of Cs5[Cr3O(OOCH)6(H2O)3][alpha-CoW12O40].7.5H2O with shape-selective adsorption of water

A polyoxometalate-macrocation ionic crystal of Cs5[Cr3O(OOCH)6(H2O)3][alpha-CoW12O40].7.5H2O (1a) was synthesized by the complexion of an inorganic metal-oxide cluster of [alpha-CoW12O40]6- and a macrocation of [Cr3O(OOCH)6(H2O)3]+. About 50% of the water of crystallization in 1a was desorbed by the evacuation to form phase 1b, and the crystallinity and crystal structure was essentially maintained by the transformation. 1b adsorbed water into the solid bulk but excluded larger alcohols. 1b was easily reusable for the separation of only water in the azeotropic mixture of ethanol and water.     

New gallium pentaphosphates: AGa2P5O16 (A=Rb,Cs)

Gallium pentaphosphates have been synthesized for the first time. These compounds, RbGa₂P₅O₁₆ and CsGa₂P₅O₁₆, are isotypic to the cesium pentaphosphates CsM₂P₅O₁₆ (M=Fe, V). They crystallize in the noncentrosymmetric Pn space group with a=7.4058(3) Å, b=9.2151(2) Å, c=10.0912(11) Å, β=110.768(8)°, V=643.9(1) Å³ (Z=2) and a=7.462(2) Å, b=9.241(3) Å, c=10.103(2) Å, β=110.731(16)°, V=651.5(3) Å³ (Z=2) for the rubidium and cesium compounds, respectively. The single crystal structure determination shows that the 3D [Ga₂P₅O₁₆]_∞ framework is rather rigid and does not vary significantly whatever M=Fe, V, Ga and A=Rb, Cs. The strongly distorted character of the pentaphosphate unit may be at the origin of strains along the P₅O₁₆ group, which explains the difficulty to stabilize pentaphosphates.