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1.
Crystal Structure of Ni4Nb2O9 Single crystals of Ni4Nb2O9 were prepared and examined by X-ray work (space group C–Fd2d; a = 10.101(13), b = 17.5126(51), c = 28.6364(87) Å; Z = 32). Ni4Nb2O9 has 480 atoms per unit cell, thus forming a complicated threedimensional NiO6-octahedra framework. NbO6-double octahedra are deposited in this framework. The relations to other A4B2O9 compounds are discussed.  相似文献   

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The crystal structure of LiEu3O4 which represents a new structure type was solved by usual methods with the aid of integrated WEISSENBERG photographs (MoKα radiation, 787 reflexions) and refined to a reliability index of 4.3%. In LiEu3O4 just as in the first known europium(II, III)-oxide, Eu3O4, a clear distinction is possible between the divalent and trivalent europium ions. The given assignment which is based on crystal chemical arguments has been verified indirectly by means of the isostructural compound LiSr2EuO4, the cation distribution of which was established experimentally. The structure of LiEu3O4 is discussed in connection with the related oxides EuO and Eu3O4. The geometrical relations to the latter are of special interest, as LiEu3O4 undergoes a topotactical transformation into Eu3O4 by heating it in a high vacuum. There is an astonishing close structural relationship between LiEu3O4 and Yb3S4: except for lithium all the atoms are correlated as for isostructural compounds.  相似文献   

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On the Crystal Structure of CuInMo2O8 . Single crystals of CuInMo2O8 were prepared and investigated by X-ray work. It shows monoclinic symmetry, space group C—C2/c; a = 9.549 Å, b = 11.529 Å, c = 5.000 Å; β = 91.38(2)°, Z = 4. CuInMo2O8 represents a LiYbW2O8 related structure, characterised by zigzag-chains of MoO6-octahedrons and octahedrons around copper and indium. With respect to LiFeW2O8 the single and three-valent ions are in opposite distribution. There are strong evidence for molybdenum in lowered oxidation state.  相似文献   

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Refinement of the Crystal Structure of K2O2 The crystal structure of K2O2 has been refined using 241 diffractometer data (Cmca; a = 6.733(1), b = 6.996(1), c = 6.474(1) Å; Z = 4; Rw = 0.050). The distance O? O (1.541(6) Å) is significantly larger than that one assumed for alkali metal peroxides, so far.  相似文献   

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Concerning Polymetaarsenites. Preparation and Crystal Structure of BaAs2O4. H2O BaAs2O4·H2O was prepared by hydrothermal reaction of BaO with As2O3 at a temperatur of 200°C. An X-ray structural analysis demonstrated that the phase contains polymetaarsenite anions [As4O84?]n, which adopt vierer single chains in the lattice. The relationship between the conformation of metaarsenite chains and cation size is discussed.  相似文献   

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The crystal structure of ditellurium(IV)-trioxide sulfate, Te2O3(SO4)—space group Pmn21–C 2v 7 ;a=8.879 (2),b=6.936 (2),c=4.646 (4) Å,Z=2—has been determined and refined by least-squares, using three-dimensionalX-ray data (1188 independent reflexions) to a final R-value of 6.3%.The crystal structure comprises puckered tellurium(IV)—oxygen layers in which the tellurium atoms are linked together by three oxygen bridges (Te–O 1.907, 1.945, 2.011 Å). The SO4 groups are arranged between these layers. Two oxygen atoms of each SO4 group are bonded to two adjacent tellurium atoms of one layer [Te–O(S) 2.270 Å] and the tellurium atoms show a (3+1) coordination. A third oxygen atom of the SO4 group is in weak interaction with two adjacent tellurium atoms of the same layer (Te–O 2.603 Å) whereas the fourth oxygen atom has distances of 2.866 Å to two adjacent tellurium atoms of the next layer and effects a very weak interaction between the

Mit 3 Abbildungen

Herrn Prof. Dr.R. Kieffer zu seinem 70. Geburtstag gewidmet.  相似文献   

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The Crystal Structure of α-CaCr2O4 Single crystals of the high temperature modifikation α-CaCr2O4 were investigated by X-Ray goniometer data. (a = 11.059, b = 5.836, c = 5.114 Å, space group D–Pmmn). α-CaCr2O4 is isotypic with SrCr2O4.  相似文献   

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The structure of Ca2As2O7 (a 0=7.05,b 0=9.30,c 0=4.89 Å; =101.3°; space groupC2/m-C 2h 3 ;Z=2) has been solved from 465 independent X-ray intensities collected on aWeissenberg-type diffractometer up to anR-factor of 2.4% for all intensities. The structure of Ca2As2O7 represents a further Thortveitite structure type.
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Preparation and Crystal Structure of Ag2O3 The novel compound Ag2O3 was obtained by anodic oxidation of aqueous solutions of AgBF4, AgClO4, and AgPF6. According to single crystal investigations Ag2O3 belongs to the orthorhombic crystal system (Fdd2; a = 1286.9(1), b = 1049.0(1), c = 366.38(5) pm; Z = 8; 309 independent diffractometer data; R = 1.2%). Ag2O3 is isostructural to Au2O3 and contains silver square-planarly coordinated by oxygen. The AgO4 groups are connected via common vertices forming a 3-d framework.  相似文献   

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Single crystals of -TlSm(WO4)2 were examined by X-ray diffractometer technique (space group C 2h 6 -C2/c;a=10.770,b=10.597,c=7.597 Å, =130.09°,Z=4). The coordination of W6+, Sm3+ and Tl+ are discribed and discussed.-TlSm(WO4)2 is isotypic to -KY(WO4)2.
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Conclusions The solubility of rubidium and cesium sulfates in aqueous solutions of sulfuric acid was studied at 25°. Rubidium sulfate forms the compounds 3Rb2SO4· H2SO4, Rb2SO4 · H2SO4, Rb2SO4·3H2SO4 and Rb2SO4·7H2SO4 with sulfuric acid, while cesium sulfate forms the compounds Cs2SO4·H2SO4; Cs2SO4·3H2SO4 and Cs2SO4 · 7H2SO4.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 6, pp. 1166–1170, June, 1968.  相似文献   

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Synthesis and Crystal Structure Determination of Pb2P4O12 · 3 H2O Pb2P4O12 · 3 H2O precipitates at mixing aqueous solutions of Pb(NO3)2 and Na4P4O12 (25°C). Crystal growth was achieved by applying gel-techniques (Agar-Agar-gel). The crystal structure (P1 , a = 786.4(3), b = 914.4(3), c = 1021.6(3) pm, α = 97.42(2)°, β = 100.63(2)°, γ = 114.92(2)°; Z = 2; 4160 unique diffractometer data, R = 0.05) contains cyclo-tetraphosphate anions with point symmetry D2d. Lead is coordinated by eight oxygen, the polyhedra deriving from a square antiprism.  相似文献   

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On the Crystal Structure of Ca2PbO4 Single crystals of Ca2PbO4 were prepared by flux technique and investigated by X-ray methods. It crystallizes with orthorhombic symmetry, space group D-Pbam. (a = 5.832; b = 9.766; c = 3.375 Å, Z = 2.) Ca2PbO4 belongs to the Sr2PbO4 type. It shows Ca2+ in a seven fold and Pb4+ in octahedral coordination.  相似文献   

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Crystal Structure of Anhydrous Na2HPO4 Na2HPO4 crystallizes monoclinic in P21/m? C with: a = 545.(1), b = 684.7(2); c = 547.3(1) pm; β = 116.34(1)°; Z = 2. The structure consists of a nearly hexagonal close-packed arrangement of HPO42? anions with Na+ in the “octahedral” and “tetrahedral” holes. The anions are orientationally disordered. Structural relationships with Na2SO4(III) and the glaserite-type of structure are discussed.  相似文献   

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Conclusions The solubility in the systems KClO4-RbClO4-H2O, KBrO3-RbBrO3-H2O, KIO3-CsIO3-H2O, RbClO4-CsClO4-H2O, RbBrO3-CsBrO3-H2O, RbIO3-CsIO3-H2O was studied at 25°. In all cases the formation of continuous series of solid solutions was established.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12, pp. 2631–2634, December, 1971.The authors would like to express their gratitude to A. I. Vulikh for his constant interest in this work and his valuable advice.  相似文献   

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