Methanesulfonates of high-valent metals: syntheses and structural features of MoO2(CH3SO3)2, UO2(CH3SO3)2, ReO3(CH3SO3), VO(CH3SO3)2, and V2O3(CH3SO3)4 and their thermal decomposition under N2 and O2 atmosphere

Oxide methanesulfonates of Mo, U, Re, and V have been prepared by reaction of MoO(3), UO(2)(CH(3)COO)(2)·2H(2)O, Re(2)O(7)(H(2)O)(2), and V(2)O(5) with CH(3)SO(3)H or mixtures thereof with its anhydride. These compounds are the first examples of solvent-free oxide methanesulfonates of these elements. MoO(2)(CH(3)SO(3))(2) (Pbca, a=1487.05(4), b=752.55(2), c=1549.61(5) pm, V=1.73414(9) nm(3), Z=8) contains [MoO(2)] moieties connected by [CH(3)SO(3)] ions to form layers parallel to (100). UO(2)(CH(3)SO(3))(2) (P2(1)/c, a=1320.4(1), b=1014.41(6), c=1533.7(1) pm, β=112.80(1)°, V=1.8937(3) nm(3), Z=8) consists of linear UO(2)(2+) ions coordinated by five [CH(3)SO(3)] ions, forming a layer structure. VO(CH(3)SO(3))(2) (P2(1)/c, a=1136.5(1), b=869.87(7), c=915.5(1) pm, β=113.66(1)°, V=0.8290(2) nm(3), Z=4) contains [VO] units connected by methanesulfonate anions to form corrugated layers parallel to (100). In ReO(3)(CH(3)SO(3)) (P1, a=574.0(1), b=1279.6(3), c=1641.9(3) pm, α=102.08(2), β=96.11(2), γ=99.04(2)°, V=1.1523(4) nm(3), Z=8) a chain structure exhibiting infinite O-[ReO(2)]-O-[ReO(2)]-O chains is formed. Each [ReO(2)]-O-[ReO(2)] unit is coordinated by two bidentate [CH(3)SO(3)] ions. V(2)O(3)(CH(3)SO(3))(4) (I2/a, a=1645.2(3), b=583.1(1), c=1670.2(3) pm, β=102.58(3), V=1.5637(5) pm(3), Z=4) adopts a chain structure, too, but contains discrete [VO]-O-[VO] moieties, each coordinated by two bidentate [CH(3)SO(3)] ligands. Additional methanesulfonate ions connect the [V(2)O(3)] groups along [001]. Thermal decomposition of the compounds was monitored under N(2) and O(2) atmosphere by thermogravimetric/differential thermal analysis and XRD measurements. Under N(2) the decomposition proceeds with reduction of the metal leading to the oxides MoO(2), U(3)O(7), V(4)O(7), and VO(2); for MoO(2)(CH(3)SO(3))(2), a small amount of MoS(2) is formed. If the thermal decomposition is carried out in a atmosphere of O(2) the oxides MoO(3) and V(2)O(5) are formed.     

Mercury(I) molybdates and tungstates: Hg2WO4 and two modifications of Hg2MoO4

The high-temperature (beta-) modification of Hg2MoO4 was prepared by solid-state reaction of HgO with MoO2 at 400 degrees C. Well-crystallized samples of the low-temperature (alpha-) modification of Hg2MoO4 and isotypic Hg2WO4 were obtained by hydrothermal recrystallization of the microcrystalline powders at 180 degrees C. The crystal structures of these transparent yellow compounds were determined by single-crystal X-ray diffractometry. beta-Hg2MoO4: P2(1)/c, Z = 4, a = 511.31(6) pm, b = 901.83(7) pm, c = 1086.0(1) pm, beta = 101.01(3) degrees. alpha-Hg2MoO4 and Hg2WO4: C2/c, Z = 4, a = 873.52(6) and 873.0(1) pm, b = 1155.19(7) and 1147.6(3) pm, c = 493.05(3) and 493.24(6) pm, beta = 115.196(5) degrees and 114.86(1) degrees, respectively. In beta-Hg2MoO4 the molybdenum atoms are tetrahedrally coordinated by oxygen atoms and the MoO4 tetrahedra are linked via Hg2 dumb-bells, thus forming infinite zigzag chains. The low-temperature (alpha-)modification of Hg2MoO4 contains MoO6 octahedra, which are linked via common edges to form zigzag chains, which are further linked via Hg2 dumb-bells, resulting in puckered two-dimensionally infinite sheets. Bonding between adjacent sheets is achieved only via weak (secondary) Hg-O bonds of 254.8 pm, while the strong Hg-O bonds of the nearly linear O-Hg-Hg-O groups within the sheets have a length of 214.8 pm. The Hg-Hg bond lengths are practically the same in the three compounds with 252.3(1), 253.49(7), and 253.3(1) pm in beta-Hg2MoO4, alpha-Hg2MoO4, and Hg2WO4, respectively. The average Mo-O distances within the MoO4 tetrahedra and the MoO6 octahedra are 176.2, and 196.5 pm, respectively. The structural chemistry of these compounds is discussed together with that of previously reported mercury I and II molybdates and tungstates.     

Phase formation in the Rb2MoO4-Er2(MoO4)3-Hf(MoO4)2 system and the crystal structure of new triple molybdate Rb5ErHf(MoO4)6

The subsolidus region of the Rb₂MoO₄-Er₂(MoO₄)₃-Hf(MoO₄)₂ ternary salt system is studied using X-ray powder diffraction. A novel 5: 1: 2 triple molybdate, Rb₅ErHf(MoO₄)₆, is found to form in the system. Crystals of Rb₅ErHf(MoO₄)₆ are flux-grown under spontaneous nucleation conditions. The composition and crystal structure of Rb₅ErHf(MoO₄)₆ are refined in a single-crystal X-ray diffraction experiment (X8 APEX diffractometer, MoK _α radiation, 1753 reflections, R = 0.0183). The crystals are trigonal; a = 10.7511(1) Å, c = 38.6543(7) Å, V = 3869.31(9) ų, d _calc = 4.462 g/cm³, Z = 6, space group $R\bar 3c$ . The mixed three-dimensional framework of the structure is formed of MoO₄ tetrahedra, each sharing corners with two ErO₆ and HfO₆ octahedra. Two types of Rb atoms occupy large cavities of the framework. The distribution of the Er³⁺ and Hf⁴⁺ cation over two positions is refined in the course of structure solution.     

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.     

[Rh(NH3)5Cl]WO4 crystal structure

At T 150 K the crystal structure of [Rh(NH₃)₅Cl]WO₄ is studied: a = 11.2374(4) Å, b = 8.4857(3) Å, c = 10.5326(3) Å, V = 1004.36(6) ų, space group Pnma, Z= 4, d _x = 3.117 g/cm³. In the structure, complex ions are bound by N—H…O hydrogen bonds, with the shortest ones of 2.85–2.94 Å. Ionic packing is shown to be considered as rhombohedral with a _t ≈ 5.26 Å, α_t ≈ 106°. Thermal properties of the salt are studied in the hydrogen atmosphere. The product of thermal decomposition at 750°C is a mixture of three solid solutions of Rh_x W _1- x based on fcc, bcc, and hcp structures. All the obtained phases are nanocrystalline. The sizes of coherent scattering regions are 10–12 nm.     

Phase equilibria in the Tl2MoO4-Nd2(MoO4)3-Hf(MoO4)2 system and the crystal structure of double molybdate TlNd(MoO4)2

The Tl₂MoO₄-Nd₂(MoO₄)₃-Hf(MoO₄)₂ system was studied in the subsolidus region using X-ray powder diffraction. New triple molybdates were found to exist in this system: Tl₅NdHf(MoO₄)₆ (5: 1: 2), TlNdHf_0.5(MoO₄)₃ (1: 1: 1), and Tl₂NdHf₂(MoO₄)_6.5 (2: 1: 4). The first TlNd(MoO₄)₂ single crystals were grown from melt solutions with spontaneous nucleation. Their crystal structure was refined from X-ray diffraction data (Bruker X8 Apex automated diffractometer, MoK _α radiation, 386 F(hkl), R = 0.0136). The tetragonal unit cell parameters are as follows: a = 6.3000(2) Å, c = 9.5188(5) Å, V = 377.80(3) ų, Z = 2, ρ_calcd = 5.876 g/cm³, space group P4/nnc. The structure is a framework built of NdO₈ and TlO₈ tetragonal antiprisms linked via shared lateral edges and alternating in the checkerboard order. Layers share oxygen vertices with MoO₄ interlayer tetrahedra and are linked into the framework.     

Rhenium oxohalides: synthesis and crystal structures of ReO3Cl(THF)2, ReOCl4(THF), Re2O3Cl6(THF)2, and Re2O3Cl6(H2O)2

Convenient methods to prepare solvated rhenium oxochlorides are described; these compounds should serve as useful starting materials for rhenium chemistry. Treatment of perrhenic acid, HReO(4), with chlorotrimethylsilane or with thionyl chloride, followed by addition of tetrahydrofuran, forms the new oxochloride complexes ReO(3)Cl(THF)(2) and ReOCl(4)(THF), respectively. Small amounts of two dinuclear oxochlorides, which evidently resulted from adventitious hydrolysis, were also isolated: Re(2)O(3)Cl(6)L(2), where L = THF or H(2)O. All four compounds were characterized by X-ray crystallography. The rhenium(vii) complex ReO(3)Cl(THF)(2) adopts a distorted octahedral geometry in which the three oxo ligands are in a facial arrangement; the rhenium(vi) complex ReOCl(4)(THF) adopts a trans octahedral structure. The two dinuclear rhenium(vi) compounds both have a single, nearly linear, bridging oxo group; on each Re center, the three terminal chlorides adopt a mer arrangement, and the terminal oxo and the coordinated Lewis base are mutually trans. The water ligand in the aqua complex is hydrogen bonded to nearby THF molecules. IR data are given.     

Phase equilibria in the Tl2MoO4-Fe2(MoO4)3-Hf(MoO4)2 system and the crystal structure of ternary molybdate Tl(FeHf0.5)(MoO4)3

The subsolidus region of the ternary salt system Tl₂MoO₄-Fe₂(MoO₄)₃-Hf(MoO₄)₂ was studied by X-ray powder diffraction. New compounds Tl₅FeHf(MoO₄)₆ (5: 1: 2) and Tl(Fe,Hf_0.5)(MoO₄)₃ (1: 1: 1). were found to be formed in this system. Crystals of new ternary molybdate of the composition Tl(FeHf_0.5)(MoO₄)₃ were grown by spontaneous flux crystallization. Its composition and crystal structure were refined based on X-ray diffraction data. The mixed three-dimensional framework of the crystal structure is composed of Mo tetrahedra sharing O vertices with (Fe,Hf)O₆ octahedra. The thallium atoms occupy wide channels in the framework.     

Binary molybdates K4M2+(MoO4)3 (M2+=Mg, Mn, Co) and crystal structure of K4Mn(MoO4)3

Binary molybdates K₄M²⁺ (MoO₄)₃ (M²⁺=Mg, Mn, Co) isostructural to triclinic \ga-K₄Zn(WO₄)₃ were synthesized, and optimal conditions for their spontaneous crystallization were found. It was established by XRPA and DTA that at 530°C the structure of the compound with cobalt undergoes a transition to the orthorhombic structure of K₄Zn(MoO₄)₃. The structure of K₄Mn(MoO₄)₃ was determined from single crystal diffraction data (a=7.613, b=9.955, c=10.156 Å,α=92.28,β=106.66,γ=105.58°, Z=2, space group $P\bar 1$ , R=0.030). In this compound, Mn has a higher coordination number (CN=5+1) than that of Zn inα-K₄Zn(WO₄)₃ (CN=4+1). The main structural feature is pairs of MnO₆ octahedra linked by the bridging MoO₄ tetrahedra into ribbons stretching along the a axis. The structure is compared with related structures of binary molybdates and other members of the alluaudite family.     

LiFe(MoO4)2, LiGa(MoO4)2 and Li3Ga(MoO4)3

The structures of lithium iron dimolybdate, LiFe(MoO₄)₂, and lithium gallium dimolybdate, LiGa(MoO₄)₂, are shown to be isomorphous with each other. Their structures consist of segregated layers of LiO₆ bicapped trigonal bipyramids and Fe(Ga)O₆ octahedra separated and linked by layers of isolated MoO₄ tetrahedra. The redetermined structure of trilithium gallium trimolybdate, Li₃Ga(MoO₄)₃, shows substitional disorder on the Li/Ga site and consists of perpendicular chains of LiO₆ trigonal prisms and two types of differently linked Li/GaO₆ octahedra.     

Apparent molar heat capacities and apparent molar volumes ofY2(SO4)3(aq),La2(SO4)3(aq),Pr2(SO4)3(aq),Nd2(SO4)3(aq),Eu2(SO4)3(aq),Dy2(SO4)3(aq),Ho2(SO4)3(aq), andLu2(SO4)3(aq)atT = 298.15 K andp = 0.1 MPa

The apparent molar heat capacities C_{p, φ} ^∘ and apparent molar volumes V_φ ^∘ of Y₂(SO₄)₃(aq), La₂(SO₄)₃(aq), Pr₂(SO₄)₃(aq), Nd₂(SO₄)₃(aq), Eu₂(SO₄)₃(aq), Dy₂(SO₄)₃(aq), Ho₂(SO₄)₃(aq), and Lu₂(SO₄)₃(aq) were measured at T =  298.15 K and p =  0.1 MPa with a Sodev (Picker) flow microcalorimeter and a Sodev vibrating-tube densimeter, respectively. These measurements extend from lower molalities of m =  (0.005 to 0.018) mol ·kg ^− 1to m =  (0.025 to 0.434) mol ·kg ^− 1, where the upper molality limits are slightly below those of the saturated solutions. There are no previously published apparent molar heat capacities for these systems, and only limited apparent molar volume information. Considerable amounts of the R SO₄ ⁺ (aq) and R(SO₄)₂ ⁻ (aq) complexes are present, where R denotes a rare-earth, which complicates the interpretation of these thermodynamic quantities. Values of the ionic molar heat capacities and ionic molar volumes of these complexes at infinite dilution are derived from the experimental information, but the calculations are necessarily quite approximate because of the need to estimate ionic activity coefficients and other thermodynamic quantities. Nevertheless, the derived standard ionic molar properties for the various R SO₄ ⁺ (aq) and R(SO₄)₂ ⁻ (aq) complexes are probably realistic approximations to the actual values. Comparisons indicate that V_φ ^∘ {RSO₄ ⁺ , aq, 298.15K}  =  − (6  ±  4)cm³· mol ^− 1and V_φ ^∘ {R(SO₄)₂ ⁻ , aq, 298.15K}  =  (35  ±  3)cm³· mol ^− 1, with no significant variation with rare-earth. In contrast, values of C_{p, φ} ^∘ { RSO₄ ⁺ , aq, 298.15K } generally increase with the atomic number of the rare-earth, whereas C_{p, φ} ^∘ { R(SO₄)₂ ⁻ , aq, 298.15K } shows a less regular trend, although its values are always positive and tend to be larger for the heavier than for the light rare earths.     

C5H14N2][(MoO3)3(SO4)].H2O: sulfated alpha-molybdena chains

Recent work in the preparation of organically templated metal sulfates under hydrothermal conditions has been extended to include the sulfation of alpha-molybdena through the synthesis of [C(5)H(14)N(2)][(MoO(3))(3)(SO(4))].H(2)O. Single crystals were grown under hydrothermal conditions from molybdenum oxide, water, sulfuric acid, and an enantiomerically pure (R)-2-methylpiperazine source and characterized using both single-crystal X-ray diffraction and infrared spectroscopy. One-dimensional [(MoO(3))(3)(SO(4))](n)(2n-) chains, based on a neutral alpha-molybdena backbone, are connected through an extensive hydrogen-bonding network containing [C(5)H(14)N(2)](2+) cations and occluded water molecules. The direction of the hydrogen bonding is primarily dictated by the nucleophilicity of the respective oxide ligands, as determined using bond valence sums.     

Cs3LiZn2(WO4)4 and Rb3Li2Ga(MoO4)4: different filled derivatives of the cation‐deficient Cs6Zn5(MoO4)8 structure

Two new compounds, namely cubic tricaesium lithium dizinc tetrakis(tetraoxotungstate), Cs₃LiZn₂(WO₄)₄, and tetragonal trirubidium dilithium gallium tetrakis(tetraoxomolybdate), Rb₃Li₂Ga(MoO₄)₄, belong to the structural family of Cs₆Zn₅(MoO₄)₈ (space group I 3d , Z = 4), with a partially incomplete (Zn_5/6□_1/6) position. In Cs₃LiZn₂(WO₄)₄, this position is fully statistically occupied by (Zn_2/3Li_1/3), and in Rb₃Li₂Ga(MoO₄)₄, the 2Li + Ga atoms are completely ordered in two distinct sites of the space group I 2d (Z = 4). In the same way, the crystallographically equivalent A ⁺ cations (A = Cs, Rb) in Cs₆Zn₅(MoO₄)₈, Cs₃LiZn₂(WO₄)₄ and isostructural A ₃LiZn₂(MoO₄)₄ and Cs₃LiCo₂(MoO₄)₄ are divided into two sites in Rb₃Li₂Ga(MoO₄)₄, as in other isostructural A ₃Li₂R (MoO₄)₄ compounds (AR = TlAl, RbAl, CsAl, CsGa, CsFe). In the title structures, the WO₄ and (Zn,Li)O₄ or LiO₄, GaO₄ and MoO₄ tetrahedra share corners to form open three‐dimensional frameworks with the caesium or rubidium ions occupying cuboctahedral cavities. The tetrahedral frameworks are related to that of mayenite 12CaO·7Al₂O₃ and isotypic compounds. Comparison of isostructural Cs₃M Zn₂(MoO₄)₄ (M = Li, Na, Ag) and Cs₆Zn₅(MoO₄)₈ shows a decrease of the cubic lattice parameter and an increase in thermal stability with the filling of the vacancies by Li⁺ in the Zn position of the Cs₆Zn₅(MoO₄)₈ structure, while filling of the cation vacancies by larger Na⁺ or Ag⁺ ions plays a destabilizing role. The series A ₃Li₂R (MoO₄)₄ shows second harmonic generation effects compatible with that of β′‐Gd₂(MoO₄)₃ and may be considered as nonlinear optical materials with a modest nonlinearity.     

[M(NH3)5Cl]WO4 (M = Cr, Rh): Synthesis, crystal structure, thermal properties

By single crystal X-ray diffraction the crystal structure of a series of [M(NH₃)₅Cl]WO₄ (M = Cr, Rh) complex salts is determined. The features of thermal expansion of the single crystal of [Cr(NH₃)₅Cl]WO₄ are studied by low- and high-temperature X-ray diffractometry in the temperature range from ?173°C to +127°C. It is shown that with an increase in the temperature, W-O distances and ∠O-W-O bond angles equalize and the average W-O distances decrease by 0.012 Å. The thermal properties of the salts in different gaseous atmospheres are examined and the phase composition of the obtained products is studied.     

Synthesis,Structure and Characterization of Three Metal Molybdate Hydrates: Fe(H2O)2(MoO4)2·H3O,NaCo2(MoO4)2(H3O2)and Mn2(MoO4)3·2H3O

Three metal molybdate hydrates,Fe(H2O)2(MoO4)2·H3O(FeMo),NaCo2(MoO4)2(H3O2)(CoMo)and Mn2(MoO4)3·2H3O(MnMo),were synthesized by the mixed-solvent-thermal methods and characterized by singlecrystal X-ray...