Dioxofluoro-oxalato-vanadat: ein fünffach koordiniertes,monomeres Komplexion des Vanadins(V)

Dioxofluorooxalatovanadate: a Monomeric, Fivefold Coordinated Complex Ion of Vanadium(V) (NH₄)₂VO₂F(C₂O₄) crystallises in the space group P2₁/c with 4 formula units per unit cell and a = 11.362(2), b = 9.503(2), c = 7.190(1) Å und β = 96.02(2)°. 1046 reflection data were refined to R = 0.038. In the complex anion vanadium is trigonal bipyramidally coordinated by two terminal oxygen atoms in cis position, fluorine and a bidentate oxalate ion. The coordination polyhedron is highly distorted. The very short bonds in the dioxo-group forming an angle of 107.5° have lengths of 1.617(4) and 1.614(4) Å. The V—O (oxalate) distances are 2.016(4) and 2.031(4) Å, the V—F distance is 1.893(3) Å. The vibrations ν_as VO₂ and ν_sVO₂ are observed at 930 and 948 cm^?1, respectively. The remaining bands of the vibrational spectra are also assigned.     

Die Kristallstruktur von Bis(N,N-Diethyl-N′-benzoylselenoureato)cadmium(II)

The Crystal Structure of Bis(N,N-Diethyl-N′-benzoylselenoureato)cadmium(II) . Cd(C₁₂H₁₅N₂OSe)₂ exists in a dimeric oxygen bridged form and crystallized in the monoclinic space group P2₁/n. The cell parameters are a = 12.506(3), b = 11.563(2), c = 18.924(4) Å, β = 91.59(3)°, Z = 4. The structure was solved with Patterson and direct methods and was refined to a final R-value of 6.58%. Cadmium is coordinated by 3 oxygen and 2 selenium atoms and exhibits the unusual coordination number 5. The coordination polyhedron is a distorted trigonal bipyramid, to bipyramids are connected by a common edge. The Cd? Se bond lengths are 2.591(1) and 2.565(1) Å, the Cd? O bond lengths are 2.263(6), 2.272(5) und 2.438(5) Å.     

K<Subscript>3</Subscript>VO<Subscript>2</Subscript>(SO<Subscript>4</Subscript>)<Subscript>2</Subscript>: Formation conditions,crystal structure,and physicochemical properties

Potassium oxosulfatovanadate(V) K₃VO₂(SO₄)₂ has been obtained by solid-phase synthesis from K₂SO₄, K₂S₂O₇, and V₂O₅ (2: 1: 1), and its formation conditions, crystal structure, and physiochemical properties have been studied. The conversions of K₃VO₂(SO₄)₂ in contact with potassium vanadates and other potassium oxosulfatovanadates(V) are considered in terms of phase relations in the K₂O-V₂O₅-SO₃ system, which models the active component of vanadium catalysts for sulfur dioxide oxidation into sulfur trioxide. The X-ray diffraction pattern of K₃VO₂(SO₄)₂ is indexed in the monoclinic system (space group P2₁) with unit cell parameters of a = 10.0408(1) Å, b = 7.2312(1) Å, c = 7.3821(1) Å, β = 104.457(1)°, Z = 2, and V = 519.02 ų. The crystal structure of K₃VO₂(SO₄)₂ is built from [VO₂(SO₄)₂]^3? complex anions, in which the vanadium atom is in an octahedral oxygen environment formed by two terminal oxygen atoms (V-O(6) = 1.605(7) Å, V-O(10) = 1.619(7) Å and four oxygen atoms of the two chelating sulfate anions. The vibrational spectra of K₃VO₂(SO₄)₂ are analyzed using these structural data.     

Contributions on thermal behaviour and crystal chemistry of anhydrous phosphates. XIX. Tri-chromium(II)-bis-phosphate Cr3(PO4)2 (≙ Cr6(PO4)4) – A transition metal(II)-orthophosphate with new structure type

Deep blue-violet single crystals of hitherto unknown chromous orthophosphate have been obtained reducing CrPO₄ by elemental Cr at temperatures above 1050°C in evacuated silica ampoules (NH₄I or I₂ as mineraliser). The complex structure of Cr₃(PO₄)₂ (P2₁2₁2₁, Z = 8, a = 8.4849(10) Å, b = 10.3317(10) Å, c = 14.206(2) Å) contains six crystallographically independent Cr²⁺ per unit cell. Five of them are coordinated by four oxygen atoms which form a distorted (roof shaped) square plane as first coordination sphere at interatomic distances 1.96 Å ? d(Cr? O) ? 2.15 Å. Their coordination is completed by additional oxygen atoms (2 or 3) at distances 2.32 Å ? d(Cr? O) ? 3.21 Å. The sixth Cr²⁺ shows six-fold octahedral coordination with strong radial distortion (d(Cr? O): 1.97, 2.04, 2.15, 2.28, 2.29, 2.53 Å). The four different [PO₄] groups exhibit only minor deviations from ideal tetrahedral geometry (1.51 Å ? d(P? O) ? 1.57 Å, 104.3° ? ∠(O? P? O) ? 114.4°). An unusually low magnetic moment μ_exp = 4.28(2) μ_B (θ_P = ?54.8(5) K) has been observed for Cr²⁺.     

Hexamethylphosphoramide Compounds: II. The Structure of a Complex Containing Two Different Coordination Polyhedra for Two Independent Neodymium(III) Ions

Abstract

The crystal structure of the complex of formula {|Nd(NCS)₃ (HMPA)₃‖ |Nd(NCS)₃ (HMPA)₄|} was determined by three-dimensional X-ray diffraction methods and refined anisotropically to a R=0.040. The compound crystallizes in the trigonal system, space group R3 (No 146), with a=19.947(3), b=19.947(3), c=20.106(3) Å, α=β=90, γ=120°, V=6928(4) ų, M=1891.4, Z=3, D_c=1.360 g cm^?3, λ(MoKα)=0.71073 Å, μ=1.4 cm^?1, F (000)=2922.01. There are two independent Nd³⁺ ions located in the three fold axis. One of them, located at the origin (000) is coordinated to nitrogen atoms of three symmetry related NCS^? anions which are below the (x y) plane (negative z) and also to the oxygen atoms of three symmetry related HMPA groups above that plane. The coordination polyhedron is a slightly distorted octahedron. The other Nd³⁺ ion is located at (00,0.5025(1)). It is coordinated to the nitrogen atoms of three symmetry related NCS^? anions above the (xy 1/2) plane and to oxygen atoms of three symmetry related HMPA groups below that plane. Another HMPA group has the O and P atoms located on the three-fold axis, above the (xy 1/2) plane. The coordination number is in this case 7 and the polyhedron is a capped trigonal antiprism. The mean distances are: Nd-N=2.44 Å, Nd-0=2.35 Å and Nd-N=2.52 Å, Nd-0=2.36 Å for the octahedron and antiprism configurations, respectively. (CNPq, FAPESP, FINEP)     

Electrochemical-hydrothermal Synthesis and Structural Characterization of Zn2(OH)VO4

A new zinc vanadate Zn₂(OH)VO₄ has been synthesized by an electrochemical-hydrothermal method and characterized by single crystal X-ray diffraction. The compound crystallizes in the orthorhombic system, space group Pnma, a = 14.645(1) Å, b = 6.0215(5) Å, c = 8.8757(8) Å, V = 782.7(1) ų, Z = 4, measured at 223 K. In the structure, rutile-type [ZnO₆] octahedral chains are interconnected by [VO₄] tetrahedra to form a framework of composition [Zn(OH)VO₄], the voids of which are filled by Zn cations with trigonal bipyramidal and octahedral coordination. The structure is closely related to that of the adamite-type phases and the minerals descloizite PbZn(OH)VO₄ and tsumcorite Pb_0.5Zn(H₂O)AsO₄.     

Synthesis,structure, and properties of M<Subscript>3</Subscript>VO<Subscript>2</Subscript>(SO<Subscript>4</Subscript>)<Subscript>2</Subscript> (M = Rb,Cs)

Vanadium(V) complexes of general composition M₃VO₂(SO₄)₂ (M = Rb, Cs) were synthesized by a solid-state route. The individuality of the synthesized compounds was proved by X-ray and neutron diffraction, vibrational spectroscopy, and microscopic analysis. The X-ray diffraction patterns of M₃VO₂(SO₄)₂ were indexed to fit the monoclinic system (space group P2/c, Z = 4) with the following unit cell parameters: a = 11.6487(2) Å, b = 8.4469(2) Å, c = 12.1110(2) Å, β = 109.483(1)°, V = 1123.43 ų (Rb); a = 12.0546(3) Å b = 8.7706(2) Å, c = 12.6496(3) Å, β = 109.843(2)°, V = 1257.99 ų (Cs). In the crystal structure of M₃VO₂(SO₄)₂, [VO₂(SO₄)₂]^3? complex anions can be discerned in which the vanadium atom is surrounded by five oxygen atoms: two oxygen atoms form short terminal V–O bonds, and three oxygen atoms are from the two sulfato groups, one of which acts as a monodentate ligand and the other acts as a bidentate chelating ligand.     

Darstellung und Kristallstruktur von Na2Mn3O7

Synthesis and Crystal-Structure of Na₂Mn₃O₇ Single crystals of Na₂Mn₃O₇ have been grown hydrothermally applying high oxygen pressure (p = 2 kbar). The new compound cystallizes triclinic; space group P1 ; a = 6.636(6) Å, b = 6.854(6) Å, c = 7.548(6) Å, α = 105.76(6)°, β = 106.86(6)°, γ = 111.60(6)°; Z = 2. The crystal structure has been solved and refined to R = 7.9% and R_w = 6.2% (diffractometer data, 1044 independent reflexions). The crystal structure consists of Mn₃O₇^2? anions with manganese coordinated octahedrally by oxygen. These layered anions are hold together by Na⁺ ions (coordination numbers 5 and 6).     

Zur Struktur eines ungewöhnlichen Tetramers des Lithiumphenolats: [C6H5OLi · C4H8O]4 · C6H5OH

The Structure of an unusual Tetramere of Lithium Phenoxide: [C₆H₅OLi · C₄H₈O]₄ · C₆H₅OH Single crystals of lithium phenoxide have been obtained from THF. In the structure (P 2₁/n, Z = 4, a = 11.69 Å, b = 21.15 Å, c = 18.55 Å, β = 91.11°) four lithium atoms and four phenoxide oxygen atoms are cubically arranged. Further, each lithium atom coordinates the oxygen atom of a tetrahydrofuran molecule. The ideal cubeform structure is disturbed by one phenol molecule which is coordinated in addition to four phenoxide and four THF molecules. Hence, one edge of the cube (Li4? O4) is substituted by the coordination of the phenol oxygen atom O5 with Li4 and hydrogen bonding between O4 and the hydroxy group of phenol. Van der Waals forces are the only interaction between these complexes.     

Investigation of the crystal and molecular structure of a novel coordination polymer formed by manganese(II) nitrate and 4,4,10,10-tetramethyl-1,3,7,9-tetraazospiro[5.5]undecan-2,8-dione

A coordination polymer {[Mn(H₂O)₂(C₁₁H₂₀N₄O₂)₂]²⁺·2(NO ₃ ^? )} _n is synthesized and its structure is determined. The crystals are monoclinic: space group P2₁/c, a = 12.3771(3) Å, b = 14.8775(3) Å, c = 18.1388(4) Å, β = 106.611(2)°, V = 3200.70(12) ų, d _x = 1.44 g/cm³, Z = 4. Manganese ions are coordinated with four oxygen atoms of four organic ligands (two unique) and two water molecules. The coordination polyhedron is a distorted octahedron; the O-Mn-O angles between the adjacent oxygen atoms fall within 83.96(5)–98.11(5)°. The nitrate anions are in the outer coordination sphere. The Mn...Mn distances in the polymer are 8.56 Å. In the crystal, polymeric coordination chains are joined in layers perpendicular to the b axis by hydrogen bonds involving the organic ligands, water molecules, and nitrate anions.     

Crystal Structure Determination of Tetrabarium‐digalliumoxide,Ba4Ga2O7

Single crystals of a new barium oxogallate were obtained by growth from a melt at 1500 °C. The compound is monoclinic, with cell parameters a = 17.7447(10) Å, b = 10.6719(5) Å, c = 7.2828(5) Å, β = 98.962(7)°, V = 1362.3(2) ų. The diffraction pattern shows systematic absences corresponding to the space group P12₁/c1. The structure was solved by direct methods followed by Fourier syntheses, and refined using a single crystal diffraction data set (R1 = 0.032 for 2173 reflections with I > 2σ(I)). The chemical composition derived from structure solution is Ba₄Ga₂O₇, with a unit cell content of Z = 6. Main building units of the structure are GaO₄ tetrahedra sharing one oxygen atom to form Ga₂O₇ groups. The Ga–O–Ga bridging angle of one of the two symmetrically independent groups is linear by symmetry. The dimers are crosslinked by barium cations coordinated by six to eight oxygen ligands.     

Die Kristallstruktur von VO2JO3·2H 2O

The Crystal Structure of VO₂IO₃·2 H₂O VO₂IO₃ possesses a layer structure and crystallizes in the space group P2₁/c with a = 9.848(3) Å, b = 8.l58(2) Å, c = 7.192(2) Å, β = 102.17(2)° and four formula units in the unit cell. The individual layers of the structure consist of highly distorted corner- and edgesharing IO₆, and VO₆, octahedra. Only one oxygen atom is bound terminally at the vanadium, as is shown by the vibrational spectrum, too.     

Synthesis and X-Ray Crystal Structure of the TiMgCl6(CH3COOC2H5)4 Adduct

The molecular and crystal structure of TiMgCl₆(CH₃COOC₂H₅)₄, obtained by reacting TiCl₄ with a solution of MgCl₂ in dry CH₃COOC₂H₅, have been determined by x-ray diffraction. The structure was solved by direct and Fourier methods and refined by least-squares techniques to R = 0.052 for 2722 independent observed reflections. Unit-cell dimensions are a = 17.122(7), b = 9.833(3), c = 9.646(3) Å, α = 111.10(7)°, β = 107.22(6)°, γ = 103.11(6)° with Z = 2 for P1 . The titanium(IV) atom is octahedrally coordinated by six chlorine atoms (Ti? Cl_t = 2.293(2) Å, Ti? Cl_b = 2.480(2) Å) and magnesium by two chlorine atoms (Mg? Cl_b = 2.528(2) Å) and the carbonyl oxygen atoms of the four CH₃COOC₂H₅ residues (Mg? O = 2.038(5) Å). The octahedra share an edge by a double chlorine bridge between the magnesium and titanium atoms. Changes in the configurations and dimensions of the free acceptor and donor molecules on adduct formation are discussed. One of the ethylacetate residues shows positional disorder, eventually with Bonding through its ethereal oxygen.     

Study of the molecular and crystal structure of a new coordination polymer of copper(II) nitrate with 4,4,10,10-tetramethyl-1,3,7,9-tetraazospiro[5.5]undecane-2,8-dione

A coordination polymer {[Cu(C₁₁H₂₀N₄O₂)₂(H₂O)]²⁺·2(NO ₃ ^? )} _n (I) is synthesized and analyzed using single-crystal XRD. The crystals are monoclinic: space group P2/c, a = 12.5237(6) Å, b = 7.3310(3) Å, c = 16.8926(8) Å, β = 92.569(4)°, V = 1549.38(13) ų, ρ_calc = 1.47 g/cm³, and Z = 2. The copper atom is in a special position in the second-order axis. The coordination polyhedron of the metal is a trigonal bipyramid. In the axial direction, it is coordinated by two oxygen atoms O(1) of the organic ligand molecules connected by the symmetry operation [?x, y, 0.5-z]; the angle O(1)Cu(1)O(1) ⁱ is 175.16(15)°. In the equatorial direction, the copper atom is coordinated by oxygen atoms O(2) of two ligand molecules connected with the reference molecule by the symmetry operations [?x, y, 0.5-z] and [x, 1-y, ?0.5+z] and the water molecule O(6) in a special position on the twofold axis. The OCuO angles between the equatorial oxygen atoms are 96.80(16)–131.60(8)°, and those between the axial and equatorial atoms are 87.58(8)-91.60(10)°. It is noteworthy that the length of the Cu-O(1) bond (1.955(2) Å) with the axial carbonyl oxygen atom is somewhat shorter than the bond (2.060(3) Å) with the equatorial atom. Nitrate anions are outside the coordination sphere of the metal. The Cu…Cu distance in the polymer is 8.33 Å. To confirm the purity of the sample of I, the powder X-ray pattern is refined by the Rietveld method; the lattice parameters at room temperature are: a = 12.535(4) Å, b = 7.3161(13) Å, c = 16.841(5) Å, β = 92.11(2)°, and V = 1543.4(7) ų.     

A structural model for barium platinum oxide,Ba3Pt2O7

A single crystal study of Ba₃Pt₂O₇ shows that the structure tolerates a variable composition which can be written Ba₃Pt_2+xO_7+2x. The crystal studied has a hexagonal cell of dimensions a = 10.108 ± 0.006 Å and c = 8.638 ± 0.009 Å, and a probable space group $\text{P}\text{6}\text{2c, Z = 4}$. The density determined by water displacement is 7.99 g/cm³; the theoretical density for Ba₃Pt₂O₇ is 7.94 g/cm³. The structure was determined from the set of 401 observed independent reflections obtained from 5189 reflections measured by automated counter methods. Refinement on F was carried to a conventional R of 8.0%. The structure has barium-oxygen layers with an essentially four-layer stacking sequence of the double hexagonal (ABAB) type. Platinum is found mainly in face-sharing octahedra, but is also distributed over some sites in which the coordination is nearly square planar and other sites in which the coordination is trigonal prismatic with three PtO bond lengths of 2.00 Å and three long PtO distances of 2.65 Å. The platinum with planar coordination is 0.08 Å from the plane of the four oxygen atoms.     

Pentastrontium Tris[tetraoxovanadate(V)] catena‐Monoxocuprate(I), Sr5(VO4)3(CuO) – An Apatite Derivative with Inserted Linear 1Ë[CuO]1– Chains

Sr₅(VO₄)₃(CuO) was prepared via solid state reactions from mixed powders of the metal oxides or carbonates in corundum crucibles in air (1173–1740 K). The compound is transparent and stable in air. The color changes with the preparation temperature from light gray (1173 K) to gray (1740 K). The crystal structure (space group P6₃/m, No. 176; Z = 2; a = 10.126 Å, c = 7.415 Å) is a derivative of the apatite Ca₅(PO₄)₃OH, and is characterized by isolated [VO₄]^3– anions (d(V–O) = 1.710 Å) and infinite linear ^1∞[CuO]^1– chains (d(Cu–O) = 1.854 Å) inserted in the channels parallel to the hexagonal axis. The compound prepared at 1740 K contains vacancies at the copper and oxygen positions of the linear chains (about 10% and 5%, respectively).     

Rietveld Analysis of a High Pressure Modification of Monocalcium Oxogallate (CaGa2O4)

A high‐pressure modification of monocalcium gallate (CaGa₂O₄) has been prepared in a piston‐cylinder apparatus at 700 °C and 4.0 GPa. The compound is orthorhombic (space group Pnam, a = 9.12476(15) Å, b = 10.56093(18) Å, c = 2.98547(4) Å, V = 287.70(1) ų, Z = 4, D_calc = 5.62 g/cm³) and belongs to the CaFe₂O₄‐type structure family. The structure was refined by the Rietveld method using laboratory X‐ray powder diffraction data. Two crystallographically independent GaO₆‐octahedra forming edge‐sharing double chains can be distinguished. The shared edges exhibit a considerable shortening. The chains are running parallel to the c‐axis and are linked by corner‐sharing. They enclose tunnels in which the calcium atoms are located for charge compensation. Each calcium cation has eight nearest oxygen neighbors. The coordination environment can be described as a bicapped trigonal prism.     

Beiträge zum thermischen Verhalten wasserfreier Phosphate. IX. Darstellung und Kristallstruktur von Cr6(P2O7)4. Ein gemischtvalentes Pyrophosphat mit zwei- und dreiwertigem Chrom

Contributions on the Thermal Behaviour of Anhydrous Phosphates. IX. Synthesis and Crystal Structure of Cr₆(P₂O₇)₄. A Pyrophosphate Containing Di- and Trivalent Chromium Cr₆(P₂O₇)₄ (Cr₂²⁺Cr₄³⁺(P₂O₇)₄) can be obtained reducing CrPO₄ by phosphorus (950°C, 48 h, 100 mg iodine as mineralizer). By means of chemical transport reactions (transport agent iodine; 1050 → 950°C) the compound has been separated from its neighbour phases (Cr₂P₂O₇, CrP₃O₉) and crystallized (greenish, transparent crystals; edge length up to 0.3 mm). The crystal structure of Cr₆(P₂O₇)₄ (Spcgrp.: P-1; z = 1; a = 4.7128(8) Å, b = 12.667(3) Å, c = 7.843(2) Å, α = 89.65(2)°, β = 92.02(2)°, γ = 90.37(2) has been solved and refined from single crystal data (2713 unique reflections, 194 parameter, R = 0.035). Cr²⁺ is surrounded by six oxygen atoms which occupy the corners of an elongated octahedron (4 × d^{Cr? O} ≈? 2.04 Å; 2 × d^{Cr? O} ≈? 2.62 Å). The Cr³⁺ ions are also coordinated octahedraly (1.930 Å ≤ d_{Cr? O} ≤ 2.061 Å). The crystallographically independent pyrophosphate groups show nearly eclipsed conformation. The bridging angles (P? O? P) are 136.5° and 138.9° respectively.     

catena‐Poly­[[di­aqua­cadmium(II)]‐μ‐5‐carboxyimidazole‐4‐carboxylato‐κ4N1,O5:O4,N3]

A new cadmium coordination polymer, [Cd(C₅H₂N₂O₄)(H₂O)₂]_n, possesses a one‐dimensional zigzag chain structure built from Cd^II centers bridged sequentially by pairs of O and N atoms of the 5‐carboxyimidazole‐4‐carboxylate ligand. The Cd^II center is in a distorted octahedral geometry, being coordinated by two O atoms from two coordinated water mol­ecules [Cd—O = 2.322 (7) and 2.364 (7) Å], and by two N atoms [Cd—N = 2.222 (6) and 2.232 (6) Å] and two carboxyl O atoms [Cd—O = 2.383 (6) and 2.414 (6) Å] from two 5‐carboxyimidazole‐4‐carboxylate ligands.     

Structure of β-SrRh2O4 from X-ray and neutron powder diffraction

β-SrRh₂O₄, a novel high temperature phase, is prepared as black powder by solid state reaction of SrCO₃ with Rh in air. The compound crystallises in the space group P63c, Z = 1, with a = 3.0626(2) Å and c = 11.3996(7) Å. The structure consists of Cd1₂-type layers of edge sharing RhO₆ octahedra with an AABB oxygen layer sequence. Strontium is found in partial occupation of both available interlayer sites, in trigonal prismatic coordination.