Subsolidus phase equilibrium in Cs2MoO4-Al2(MoO4)3-Zr(MoO4)2 system and crystal structure of new ternary molybdate Cs(AlZr0.5)(MoO4)3

The subsolidus area of Cs₂MoO₄-Al₂(MoO₄)₃-Zr(MoO₄)₂ system was studied by X-ray powder diffraction. Two new molybdates with component molar ratios of 1: 1: 1 (S₁) and 5:1:2 (S₂) were synthesized for the first time. The crystallographic parameters of the 5:1:2 compound were determined. Solution- melt crystallization and spontaneous nucleation yielded crystals of new 1:1:1 cesium aluminum zirconium molybdate Cs(AlZr_0.5)(MoO₄)₃. Its formula unit and crystal structure were refined by X-ray diffraction (1592 reflections, R=0.0249). Trigonal crystals: a=12.9441(2) ?, c=12.0457(4) ?, V=1747.86(7) ?³, Z = 6, space group R $ \bar 3 $ \bar 3 . The three-dimensional combined framework of this structure is formed by MoO₄ tetrahedrons linked through common vertices to (Al,Zr)O₆ octahedrons. Cesium atoms occupy large cavities of the framework. Crystallographic position M(1) is occupied by randomly distributed Al³⁺ and Zr⁴⁺ cations.     

Crystal structure of binary molybdate Pr2Hf3(MoO4)9

Crystals of binary praseodymium and hafnium molybdate of Pr₂Hf₃(MoO₄)₉ composition are grown by solution-melt crystallization under spontaneous nucleation conditions. By the X-ray diffraction data (X8 Apex automated diffractometer, MoK _α radiation, 2262 F(hkl), R = 0.0170) its composition and crystal structure are determined. Parameters of the trigonal unit cell are: a = b = 9.8001(1) ? c = 58.7095(8) ?, V = 4883.15(10) ?³, Z = 6, space group R c. The crystal structure is composed of three types of polyhedra: MoO₄ tetrahedra, HfO₆ octahedra, and nine-vertex PrO₉. All three types of polyhedra are bonded among themselves by common oxygen vertices of bridging MoO₄ tetrahedra forming an openwork three-dimensional structure. Original Russian Text Copyright ? 2009 by B. G. Bazarov, V. G. Grossman, R. F. Klevtsova, A. G. Anshits, T. A. Vereshchagina, L. A. Glinskaya, Yu. L. Tushinova, K. N. Fedorov, and Zh. G. Bazarova __________ Translated from Zhurnal Strukturnoi Khimii, Vol. 50, No. 3, pp. 587–590, May–June, 2009.     

Phase formation in Cs2MoO4-MMoO4-Zr(MoO4)2 (M = Mn, Mg, Co, Zn) systems and crystal structure of new double molybdates Cs2MnZr2(MoO4)6 and Cs2MnZr(MoO4)4

Subsolidus phase relations in the Cs₂MoO₄-MMoO₄-Zr(MoO₄)₂ (M = Mn, Zn) ternary systems were determined, and two groups of new isostructural triple molybdates were synthesized: Cs₂MZr(MoO₄)₄ and Cs₂MZr₂(MoO₄)₆ (M = Mn, Mg, Co, Zn). Cs₂MnZr₂(MoO₄)₆ and Cs₂MnZr(MoO₄)₄ crystals were grown by spontaneous flux crystallization and used in structure solution for both groups of compounds. The Cs₂MnZr₂(MoO₄)₆ structure (a =13.4322(2) ?, c = 12.2016(3) ?, group R3, Z = 3, R = 0.0367) is a new structure type characterized by a mixed three-dimensional framework built of corner-sharing MoO₄ tetrahedra and (M, Zr)O₆ octahedra where large channels are occupied by cesium cations. Cs₂MnZr₂(MoO₄)₄ (a =5.3890(1) ?, c = 8.0685(3) ?, space group P $ \bar 3 $ \bar 3 m1, Z = 0.5, R = 0.0247) has the layered glaserite-like KAl(MoO₄)₂ type structure, where Al³⁺ octahedral positions are randomly occupied by a 0.5M²⁺ + 0.5Zr⁴⁺ mixture.     

Structures of three polymorphs of the complex oxide K5Yb(MoO4)4

Polymorphous modifications (γ-, β- and α-) of the double potassium ytterbium molybdenum oxide K₅Yb(MoO₄)₄ were synthesized by the solid-state method and their structures were studied by X-ray powder diffraction, electron diffraction and high-resolution electron microscopy. DSC analysis shows that the γ→β↔α phase transitions are not accompanied with a significant reconstruction of the palmierite-type structure. All modifications of K₅Yb(MoO₄)₄ are related to the mineral palmierite—K₂Pb(SO₄)₂. The palmierite-type structure is made up of isolated AO₄ tetrahedra, which connect the MO_n polyhedra into a 3-D framework via common vertices. Cations occupy two crystallographic positions M1 and M2. The γ-phase crystallizes in a monoclinic system (space group C2/c) with unit-cell parameters: a=14.8236(1) Å, b=12.1293(1) Å, c=10.5151(1) Å, β=114.559(1)°, Z=4. The α-phase has space group with unit-cell parameters: a=6.0372(1) Å, c=20.4045(2) Å. The structures of the γ- and α-modification were refined by the Rietveld method (R_wp=6.25%, R_I=2.16% and R_wp=9.09%, R_I=5.80% for γ- and α-, respectively). In K₅Yb(MoO₄)₄ ytterbium cations occupy M1 while K⁺ cations occupy M2 and M1 positions of the palmierite-type structure. In the high-temperature (α-) modification the Yb³⁺ and K⁺ occupy the M1 site in a statistical manner (M1=0.5Yb³⁺+0.5K⁺) while in the low-temperature (γ-) modification these cations occupy this site in an ordered way. The intermediate β-phase shows an incommensurate modulated structure.     

Interactions in the subsolidus region of the Na2MoO4-NiMoO4-Fe2(MoO4)3 system

Phase relations have been investigated in the subsolidus region of the Na₂MoO₄-NiMoO₄-Fe₂(MoO₄)₃ system by X-ray diffraction, differential thermal analysis, and vibrational spectroscopy. The phase of variable composition Na_1−x Ni_1−x Fe_1+x (MoO₄)₃(0≤x≤0.5) with the NASICON structure (space group R c) and the NaNi₃Fe(MoO₄)₅ ternary molybdate crystallizing in the triclinic crystal system (space group P ) have been obtained. A high conductivity was found in Na_1−x Ni_1−x Fe_1+x (MoO₄)₃, which allows one to consider this phase of variable composition as a promising solid electrolyte with sodium ion conduction. Original Russian Text ? N.M. Kozhevnikova, A.V. Imekhenova, 2009, published in Zhurnal Neorganicheskoi Khimii, 2009, Vol. 54, No. 4, pp. 695–700.     

Synthesis, crystal structure and electrical characterization of two new potassium uranyl molybdates K2(UO2)2(MoO4)O2 and K8(UO2)8(MoO5)3O6

Two new potassium uranyl molybdates K₂(UO₂)₂(MoO₄)O₂ and K₈(UO₂)₈(MoO₅)₃O₆ have been obtained by solid state chemistry . The crystal structures were determined by single crystal X-ray diffraction data, collected with MoKα radiation and a charge coupled device (CCD) detector. Their structures were solved using direct methods and Fourier difference techniques and refined by a least square method on the basis of F² for all unique reflections, with R₁=0.046 for 136 parameters and 1412 reflections with I?2σ(I) for K₂(UO₂)₂(MoO₄)O₂ and R₁=0.055 for 257 parameters and 2585 reflections with I?2σ(I) for K₈(UO₂)₈(MoO₅)₃O₆. The first compound crystallizes in the monoclinic symmetry, space group P2₁/c with a=8.250(1) Å, b=15.337(2) Å, c=8.351(1) Å, β=104.75(1)°, ρ_mes=5.22(2) g/cm³, ρ_cal=5.27(2) g/cm³ and Z=4. The second material adopts a tetragonal unit cell with a=b=23.488(3) Å, c=6.7857(11) Å, ρ_mes=5.44(3) g/cm³, ρ_cal=5.49(2) g/cm³, Z=4 and space group P4/n.In both structures, the uranium atoms adopt a UO₇ pentagonal bipyramid environment, molybdenum atoms are in a MoO₄ tetrahedral environment for K₂(UO₂)₂(MoO₄)O₂ and MoO₅ square pyramid coordination in K₈(UO₂)₈(MoO₅)₃O₆. These compounds are characterized by layered structures. The association of uranyl ions (UO₇) and molybdate oxoanions MoO₄ or MoO₅, give infinite layers [(UO₂)₂(MoO₄)O₂]²⁻ and [(UO₂)₈(MoO₅)₃O₆]⁸⁻ in K₂(UO₂)₂(MoO₄)O₂ and K₈(UO₂)₈(MoO₅)₃O₆, respectively. Conductivity properties of alkali metal within the interlayer spaces have been measured and show an Arrhenius type evolution.     

Refinement of Phase Formation in the Na2MoO4-Hf(MoO4)2 System. Crystal Structure of the New Binary Molybdate Na8Hf(MoO4)6

Phase equilibria in the subsolidus region of the Na₂MoO₄-Hf(MoO₄)₂ system have been investigated. The existence of Na₂Hf(MoO₄)₃ was confirmed, and a new binary molybdate, Na₈Hf(MoO₄)₆, has been found, whose crystal structure with dimensions a = 20.661(3) Å, b = 9.816(1) Å, c = 13.796(3) Å, β = 113.47(1)°, Z = 4, space group C2/_c, _R = 0.023 is similar to that of K₈Hf(MoO₄)₆. In the structure, each HfO₆ octahedron is linked (through common vertices) to six MoO₄ tetrahedra, forming [Hf(MoO₄)₆]⁸⁻ cluster groups. Between the groups are Na⁺ ions having considerably distorted tetragonal pyramidal or octahedral oxygen surroundings; c.n. of sodium here is 5 or 6 versus c.n. = 7–9 of potassium in K₈Hf(MoO₄)₆. The open irregular environment of sodium and the continuous three-dimensional openwork of oxygen polyhedra around sodium suggest that Na₈Hf(MoO₄)₆ or its analogs may be good ion conductors.Original Russian Text Copyright © 2004 by S. F. Solodovnikov, B. G. Bazarov, L. V. Balsanova, Z. A. Solodovnikova, and Zh. G. Bazarova__________Translated from Zhurnal Strukturnoi Khimii, Vol. 45, No. 6, pp. 1044–1048, November–December, 2004.     

Crystal Structure of Ternary Molybdate Rb5FeHf(MoO4)6 — a New Phase in the Rb2MoO4-Fe2(MoO4)3-Hf(MoO4)2 System

Physicochemical analysis (XRPA, DTA) was used to study phase equilibria in a ternary salt system Rb₂MoO₄-Fe₂(MoO₄)₃-Hf(MoO₄)₂ in the subsolidus region. Ternary molybdates with compositions 5:1:3, 5:1:2, and 1:1:1 have been found and synthesized. Crystal and thermal characteristics have been determined. Single crystals of the ternary molybdate Rb₅FeHf(MoO₄)₆ with a composition of 5:1:2 were grown. The crystal structure of the compound was solved using X-ray diffractometry (CAD-4 automatic diffractometer, MoK _α radiation, 1766 F(hkl), R = 0.0298). Hexagonal crystals with unit cell dimensions: a = b = 10.124(1) Å, c =15.135(3) Å, V = 1343.4(4) ų, Z = 2, ρ_calc = 4.008 g/cm³, space group P6₃. The mixed three-dimensional framework of the structure is formed from two sorts of MoO₄ tetrahedra and Fe and Hf octahedra linked through their common O-vertices. Rubidium atoms of three varieties occupy the large voids of the framework.Original Russian Text Copyright © 2004 by B. G. Bazarov, R. F. Klevtsova, A. D. Tsyrendorzhieva, L. A. Glinaskaya, and Zh. G. Bazarova__________Translated from Zhurnal Strukturnoi Khimii, Vol. 45, No. 6, pp. 1038–1043, November–December, 2004.     

Subsolidus phase relations in the Na2MoO4-CoMoO4-Cr2(MoO4)3 system

Triple molybdate NaCoCr(MoO₄)₃, a phase of variable composition Na₂MoO₄-CoMoO₄-Cr₂(MoO₄)₃ (0 ≤ x ≤ 0.5) having nasicon structure (space group R $ \bar 3 $ \bar 3 c), and triple molybdate NaCo₃Cr(MoO₄)₅ crystallizing in triclinic space group P $ \bar 1 $ \bar 1 were synthesized in the subsolidus region of the Na₂MoO₄-CoMoO₄-Cr₂(MoO₄)₃ ternary salt system. Crystal parameters were calculated for the newly synthesized molybdates and phases. The vibration spectra of Na_{1 − x} Co_{1 − x} Cr_{1 + x} (MoO₄)₃ and electrophysical properties were studied. Upon Na + Co → Cr(III) substitution, chromium cations are distributed to cobalt sites and additional vacancies are generated in the sodium sublattice.     

Crystal structure and magnetic properties of Li,Cr-containing molybdates Li3Cr(MoO4)3, LiCr(MoO4)2 and Li1.8Cr1.2(MoO4)3

Single crystals of LiCr(MoO₄)₂, Li₃Cr(MoO₄)₃ and Li_1.8Cr_1.2(MoO₄)₃ were grown by a flux method during the phase study of the Li₂MoO₄-Cr₂(MoO₄)₃ system at 1023 K. LiCr(MoO₄)₂ and Li₃Cr(MoO₄)₃ single phases were synthesized by solid-state reactions. Li₃Cr(MoO₄)₃ adopts the same structure type as Li₃In(MoO₄)₃ despite the difference in ionic radii of Cr³⁺ and In³⁺ for octahedral coordination. Li₃Cr(MoO₄)₃ is paramagnetic down to 7 K and shows a weak ferromagnetic component below this temperature. LiCr(MoO₄)₂ is isostructural with LiAl(MoO₄)₂ and orders antiferromagnetically below 20 K. The magnetic structure of LiCr(MoO₄)₂ was determined from low-temperature neutron diffraction and is based on the propagation vektor . The ordered magnetic moments were refined to 2.3(1) μ_B per Cr-ion with an easy axis close to the [1 1 1¯] direction. A magnetic moment of 4.37(3) μ_B per Cr-ion was calculated from the Curie constant for the paramagnetic region.The crystal structures of the hitherto unknown Li_1.8Cr_1.2(MoO₄)₃ and LiCr(MoO₄)₂ are compared and reveal a high degree of similarity: In both structures MoO₄-tetrahedra are isolated from each other and connected with CrO₆ and LiO₅ via corners. In both modifications there are Cr₂O₁₀ fragments of edge-sharing CrO₆-octahedra.     

Combinatorial topology of uranyl molybdate sheets: syntheses and crystal structures of (C6H14N2)3[(UO2)5(MoO4)8](H2O)4 and (C2H10N2)[(UO2)(MoO4)2]

Two new mixed organic-inorganic uranyl molybdates, (C₆H₁₄N₂)₃[(UO₂)₅(MoO₄)₈](H₂O)₄ (1) and (C₂H₁₀N₂)[(UO₂)(MoO₄)₂] (2), have been obtained by hydrothermal methods. The structure of 1 [triclinic, , Z=1, a=11.8557(9), b=11.8702(9), c=12.6746(9) Å, α=96.734(2)°, β=91.107(2)°, γ=110.193(2)°, V=1659.1(2) Å] has been solved by direct methods and refined on the basis of F² for all unique reflections to R1=0.058, which was calculated for the 5642 unique observed reflections (|F_o|?4σ_F). The structure contains topologically novel sheets of uranyl square bipyramids, uranyl pentagonal bipyramids, and MoO₄ tetrahedra, with composition [(UO₂)₅(MoO₄)₈]⁶⁻, that are parallel to (−101). H₂O groups and 1,4-diazabicyclo [2.2.2]-octane (DABCO) molecules are located in the interlayer, where they provide linkage of the sheets. The structure of 2 [triclinic, , Z=2, a=8.4004(4), b=11.2600(5), c=13.1239(6) Å, α=86.112(1)°, β=86.434(1)°, γ=76.544(1)°, V=1203.14(10) Å] has been solved by direct methods and refined on the basis of F² for all unique reflections to R1=0.043, which was calculated for 5491 unique observed reflections (|F_o|?4σ_F). The structure contains topologically novel sheets of uranyl pentagonal bipyramids and MoO₄ tetrahedra, with composition [(UO₂)(MoO₄)₂]²⁻, that are parallel to (110). Ethylenediamine molecules are located in the interlayer, where they provide linkage of the sheets. All known topologies of uranyl molybdate sheets of corner-sharing U and Mo polyhedra can be described by their nodal representations (representations as graphs in which U and Mo polyhedra are given as black and white vertices, respectively). Each topology can be derived from a simple black-and-white graph of six-connected black vertices and three-connected white vertices by deleting some of its segments and white vertices.     

Phase formation in the Dy2O3-HfO2-MoO3 system. Crystal structure of the new binary molybdate Dy2Hf2(MoO4)7

Phase relations have been studied for the subsolidus region of the Dy₂O₃-HfO₂-MoO₃ system; binary molybdates, Dy₂Hf(MoO₄)₅ and Dy₂Hf₂(MoO₄)₇, were found to form. The crystal structure of the latter has been solved (a = 20.661(3) , b = 9.816(1) , c = 13.796(3) , = 113.47(1)°, Z = 4, space group C2/c, R = 0.023) and found to be a new type of structure. In the structure, MoO₄ tetrahedra are linked by their vertices with HfO₆ octahedra and DyO₈ tetragonal antiprisms to form a 3D open-work, in which one can isolate double-row tetrahedral and octahedral chains extended down the c axis.Original Russian Text Copyright © 2004 by S. F. Solodovnikov, B. G. Bazarov, E. Yu. Badmaeva, Yu. L. Tushinova, E. S. Zolotova, and Zh. G. BazarovaTranslated from Zhurnal Strukturnoi Khimii, Vol. 45, No. 4, pp. 692–697, July–August, 2004.This revised version was published online in April 2005 with a corrected cover date.     

Ba3 (VO4)2-K2 Ba(MoO4)2 and Pb3 (VO4)2-K2 Pb(MoO4)2 systems

Phase equilibria in the Ba₃(VO₄)₂-K₂Ba(MoO₄)₂ and Pb3(VO₄)₂-K₂Pb(MoO₄)₂ systems have been investigated. In the first system, a continuous series of substitutional solid solutions with the palmierite structure is formed, and in the second one, the polymorphic transition in lead orthovanadate at 100°C restricts the extent of the palmierite-type solid solution to 10–100 mol % K₂Pb(MoO₄)₂. Original Russian Text ? V.D. Zhuravlev, Yu.A. Velikodnyi, A.S. Vinogradova-Zhabrova, A.P. Tyutyunnik, V.G. Zubkov, 2008, published in Zhurnal Neorganicheskoi Khimii, 2008, Vol. 53, No. 10, pp. 1746–1748.     

Phase formation in the Ag2MoO4-CuO-MoO3 system and the crystal structure of the new double molybdate Ag2Cu2(MoO4)3

Subsolidus phase relations in the Ag₂MoO₄-CuO-MoO₃ oxide-salt ternary system were determined. T-x diagram was plotted for the Ag₂MoO₄-CuMoO₄ quasi-binary join. Double molybdate Ag₂Cu₂(MoO₄)₃ was found to exist on this join. This compound is a superstructure derived from orthorhombic Li₃Fe(MoO₄)₃. Its structure was solved in terms of a subcell (a = 5.0749(3), b = 11.300(2), c = 18.127(3) ?, space group Pnma, Z = 4, R = 0.0678). In the true unit cell, the parameter a is tripled; suggested space group is P2₁2₁2₁. A characteristic feature of the Ag₂Cu₂(MoO₄)₃ structure is infinite columns (extended along axis a) of face-sharing oxygen octahedra, in which disordered silver atoms are located (Ag(21), Ag(22), and Ag(23)) with various degrees of irregularity of their octahedral coordination and a strong anisotropy of thermal vibrations. Distorted CuO₆ octahedra form zigzag ribbons extended in the same direction. MoO₄ tetrahedra, which are arranged according to the pseudo-hexagonal law, link the aforementioned major structural elements into a three-dimensional framework. Trigonal-prismatic voids of the framework are occupied by silver atoms Ag (1). Presumably, the disorder of the silver ions in octahedral columns can be responsible for the increased ion conductivity of silver copper molybdate. A partial order of the same ions is the most likely reason for the appearance of superstructure with the tripled unit cell volume. Original Russian Text ? G.D. Tsyrenova, S.F. Solodovnikov, E.T. Pavlova, E.G. Khaikina, Z.A. Solodovnikova, 2009, published in Zhurnal Neorganicheskoi Khimii, 2009, Vol. 54, No. 5, pp. 802–809.     

Crystal structures of phosphomolybdyl salts: Pb(MoO2)2(PO4)2 and Ba(MoO2)2(PO4)2

Crystal structures of Pb(MoO₂)₂(PO₄)₂ and Ba(MoO₂)₂(PO₄)₂ were determined. Both compounds contain the molybdyl group MoO₂. The monoclinic unit-cell parameters are a = 6.353(7), b = 12.289(4), c = 11.800 Å, β = 92°56(6), and Z = 4 for the lead salt and a = 6.383(8), b = 7.142(7), c = 9.953(8) Å, β = 95°46(8), and Z = 2 for the barium salt. $\text{P2}{}_1\text{c}$ is the common space group. The R values are respectively R = 0.027 and R = 0.031 for 1964 and 1714 independent reflections. The frameworks built up by a three-dimensional network of monophosphate PO₄ and molybdyl MoO₂ groups are similar, characterized mainly by corner-sharing PO₄ and MoO₆ polyhedra. Two oxygen atoms of each MoO₆ group are bonded to the molybdenum atom only as in other molybdyl salts.     

Supramolecular pseudometallacycles in a nickel compound with 4,4-diaminodiphenylmethane: Synthesis and structure of {Ni[(CH2(C6H4NH2)2]2(NO3)2(H2O)2}

The [Ni(DDM)₂(NO₃)₂(H₂O)₂] complex (DDM is 4,4-diaminodiphenylmethane [CH₂(C₆H₄NH₂)₂]) is synthesized, and its structure is determined. The crystals are triclinic, space group P , a = 5.846(1) ?, b = 9.450(2) ?, c = 13.390(3) ?, α = 105.63(3)°, β = 98.13(3)°, γ = 105.84(3)°, V = 666.6(2) ?³, ρ_calcd = 1.553 g/cm³, Z = 2. The Ni(II) ion (in the inversion center) is bound to a distorted octahedral array formed by the nitrogen atoms of the primary amino groups of the DDM molecules and the oxygen atoms of the monodentate nitrato groups and water molecules (Ni(1)-N(3) 2.119(2) ?, Ni(1)-O(1) 2.122(2) ?, Ni(1)-O(w) 2.047(2) ?, angles at the Ni atoms vary in the 85.08(9)°–94.92(9)° interval). The structure contains supramolecular metallacycles formed by the O(w)-H…N(2) hydrogen bonds between the coordinated H₂O molecules and the terminal amino groups of DDM. The metallacycles are joined by the Ni²⁺ ions into infinite chains running in the [111] direction. Original Russian Text ? Yu.V. Kokunov, V.V. Kovalev, Yu.E. Gorbunova, 2008, published in Zhurnal Neorganicheskoi Khimii, 2008, Vol. 53, No. 11, pp. 1838–1843.     

Zinc citrate with alkali metal and ammonium cations: Crystal structure of K4[Zn(Citrate)2]

In the crystal of K₄[Zn(Citrate)₂], two citrate anions coordinate Zn(II) cation with octahedral geometry in the [Zn(Citrate)₂]⁴⁻ complex anion, and the charge is balanced by four potassium ions. Crystal data: monoclinic, P2₁/c, a = 8.502(2) ?, b = 13.210(3) ?, c = 8.942(2) ?, β = 113.132(4)°, V = 923.5(4) ?³, Z = 2, R = 0.0229.     

Syntheses and single-crystal structures of CsTh(MoO4)2Cl and Na4Th(WO4)4

Colorless crystals of CsTh(MoO₄)₂Cl and Na₄Th(WO₄)₄ have been synthesized at 993 K by the solid-state reactions of ThO₂, MoO₃, CsCl, and ThCl₄ with Na₂WO₄. Both compounds have been characterized by the single-crystal X-ray diffraction. The structure of CsTh(MoO₄)₂Cl is orthorhombic, consisting of two adjacent [Th(MoO₄)₂] layers separated by an ionic CsCl sublattice. It can be considered as an insertion compound of Th(MoO₄)₂ and reformulated as Th(MoO₄)₂·CsCl. The Th atom coordinates to seven monodentate MoO₄ tetrahedra and one Cl atom in a highly distorted square antiprism. Na₄Th(WO₄)₄ adopts a scheelite superlattice structure. The three-dimensional framework of Na₄Th(WO₄)₄ is constructed from corner-sharing ThO₈ square antiprisms and WO₄ tetrahedra. The space within the channels is filled by six-coordinate Na ions. Crystal data: CsTh(MoO₄)₂Cl, monoclinic, P2₁/c, Z=4, a=10.170(1) Å, b=10.030(1) Å, c=9.649(1) Å, β=95.671(2)°, V=979.5(2) Å³, R(F)=2.65% for I>2σ(I); Na₄Th(WO₄)₄, tetragonal, I4₁/a, Z=4, a=11.437(1) Å, c=11.833(2) Å, V=1547.7(4) Å³, R(F)=3.02% for I>2σ(I).     

Phase equilibrium in the Cs2MoO4-Bi2(MoO4)3-Zn(MoO4)2 system and the crystal structure of new triple molybdate Cs5BiZr(MoO4)6

The subsolidus region of the Cs₂MoO₄-Bi₂(MoO₄)₃-Zr(MoO₄) system was studied by X-ray powder diffraction. Quasi-binary sections were elucidated, and triangulation performed. Triple molybdates with the component ratios 5: 1: 2 (S ₁) and 2: 1: 4 (S ₂) were prepared for the first time. Crystals of cesium bismuth zirconium molybdate of the 5: 1: 2 stoichiometry (Cs₅BiZr(MoO₄)₆) were grown from fluxed melts with spontaneous nucleation. The composition and crystal structure of this triple molybdate were refined using X-ray diffraction data (collected on X8 APEX automated diffractometer, MoK _α radiation, 2348 F(hkl), R = 0.0226). The trigonal unit cell parameters were as follows: a = b = 10.9569(2), c = 39.804(4) Å, V = 4138.4(4) ų, Z = 6, space group R $ \bar 3 The subsolidus region of the Cs₂MoO₄-Bi₂(MoO₄)₃-Zr(MoO₄) system was studied by X-ray powder diffraction. Quasi-binary sections were elucidated, and triangulation performed. Triple molybdates with the component ratios 5: 1: 2 (S ₁) and 2: 1: 4 (S ₂) were prepared for the first time. Crystals of cesium bismuth zirconium molybdate of the 5: 1: 2 stoichiometry (Cs₅BiZr(MoO₄)₆) were grown from fluxed melts with spontaneous nucleation. The composition and crystal structure of this triple molybdate were refined using X-ray diffraction data (collected on X8 APEX automated diffractometer, MoK _α radiation, 2348 F(hkl), R = 0.0226). The trigonal unit cell parameters were as follows: a = b = 10.9569(2), c = 39.804(4) ?, V = 4138.4(4) ?³, Z = 6, space group R c. The mixed-metal three-dimensional framework in this structure is built of Mo tetrahedra and two sorts of (Bi,Zr)O₆ octahedra. Large interstices accommodate two sorts of cesium atoms. The Bi³⁺ and Zr⁴⁺ cation distributions over two positions were refined during structure solution. Original Russian Text ? B.G. Bazarov, T.V. Namsaraeva, R.F. Klevtsova, A.G. Anshits, T.A. Vereshchagina, R.V. Kurbatov, L.A. Glinskaya, K.N. Fedorov, Zh.G. Bazarova, 2008, published in Zhurnal Neorganicheskoi Khimii, 2008, Vol. 53, No. 9, pp. 1585–1589.     

Synthesis, characterization and crystal structure of K2Bi(PO4)(MoO4)

A new potassium bismuth phosphate-molybdate K₂Bi(PO₄)(MoO₄) has been synthesized by the flux method and characterized by single-crystal and powder X-ray diffraction, IR spectroscopic studies. The compound crystallizes in the orthorhombic system with the space group Ibca and the cell parameters: a=19.7037(10), b=12.4752(10), c=7.0261(10). This phase exhibits an original layered structure, in which the [Bi(PO₄)(MoO₄)]_∞ layers consist of [Bi₂Mo₂O₁₈]_∞ chains linked through single PO₄ tetrahedra. The K⁺ cations interleaved between these layers exhibit a monocapped distorted cubic coordination.