Crystal and molecular structure ofcis-dicarbonyltetraphosphinechromium(O), [(CO)2(PH3)4Cr]

The crystal and molecular structure ofcis-dicarbonyltetraphosphinechromium(O), [(CO)₂(PH₃)₄Cr] has been determined by X-ray diffraction methods. The compound crystallizes in the monoclinic system: space groupC2/c,a = 6·968(6),b = 11·98(1),c = 12·87(1) Å, = 99·80(8) °,V= 1059(3) ų,Z=4,D _m = 1·534(5),D _x = 1·531(5) gcm^–3, diffraction symmetry 2/m. The structure was solved by conventional methods, and refined by least-squares techniques to an agreement factorR = 0·078. The chromium atoms lie on rotation diads, and thus the molecules must have at least the symmetry 2(C ₂); they were found to have, within the limits of accuracy, the even higher symmetrymm2 (C _2v ). There are two distinct independent Cr-P distances in the molecule, the Cr-P bonds where phosphorus istrans to carbonyl [2·338(4) Å] being significantly longer than those where phosphorus istrans to phosphine [2·282(4) Å]. This difference may be attributed to a difference in the back-bonding capabilities of the two types of ligands.We wish to thank Professor Dr E. O. Fischer for his stimulating interest in this work. Our thanks are due also to the Leibniz Rechenzentrum der Bayerischen Akademie der Wissenschaften for use of their computing facilities. This work would not have been possible without a generous grant from the Deutsche Forschungsgemeinschaft which is gratefully acknowledged.     

Crystal structure of vanadocene (η5-C5H5)2V

The crystal structure of vanadocene has been determined from counter data, and refined by full-matrix least-squares techniques. The crystals belong to the monoclinic space groupP2₁/n witha = 9.269(3),b = 8.020(3),c = 5.892(2) Å, = 91.21(3)°, andD _x = 1.37 gcm^-3 for Z = 2. The finalR value for 583 observed reflections is 0.031. The vanadium atom resides on a crystallographic center of inversion. The cyclopentadienyl groups are statistically disordered 70–30%. The average vanadium-carbon (⁵) bond distance is 2.26(2) Å.     

Crystal structure of osmocene,Os(η-C5H5)2

Crystals of osmocene, Os(-C₅H₅)₂, are orthohombic:Pnma,M _r =321.3,a=7.079(2),b=8.908(1),c=12.771(2),V _c =806 ų,Z=4,D _x =2.640 g cm^–3, MoK (=0.71069 Å),=151 cm^–1,F(000)=584,T=293 K,R=0.04 for 730 observed reflections. Osmocene is isomorphous with ruthenocene and the molecules have averageD _5h symmetry with a mean Os-C distance of 2.19(1) Å (compared with 2.186 Å forRu-C).Part 26 of the series Cyclopentadienyl-ruthenium and -osmium chemisty. For Part 25, see Bruce, etal. (1985).     

Crystal structure of bis(2-butyl-4-chloro-imidazole)5-iminoethane

The title compound (C₁₈H₂₆N₆Cl₂) crystallizes in monoclinic space group P2₁/c with a = 14.867(4) Å}, b = 7.758(2) Å}, c = 9.671(3) Å}, = 108.78(1), V = 1056.0(5) Å}³, Z = 2, D_cal = 1.250 Mg/m³ at T = 293 K. The structure was solved by direct methods and refined by full-matrix least-squares procedures to final R = 0.0650 and wR = 0.1719 using 2493 reflections. The imidazole ring is planar and the n-butyl chain adopts an extended conformation. The molecules in the crystal are stabilized by N–H s N type of intermolecular hydrogen bondings in addition to van der Waals forces.     

Crystal structure of [WI2(CO)3{P(OMe)3}2]

[WI₂(CO)₃{P(OMe)₃}₂]crystallizes in the orthorhombic space group Pca2₁, with a = 26.924(5), b = 10.726(2), c = 14.136(3) Å, and Z = 8. There are two molecules in the asymmetric unit, the metal atoms in each case being seven-coordinate with a capped fac-(CO)₃ octahedral geometry. The molecular dimensions in the two molecules are nearly identical. The W–P distance to the capping atom 2.397 Å (average) is significantly shorter than the other W–P distance, 2.525 Å (average).     

Crystal structure of the new barium borate Ba5(BO3)2(B2O5)

The crystal structure of the new barium borate Ba₅(BO₃)₂(B₂O₅) is established (R = 0.0436). Single crystals were grown by spontaneous crystallization in the BaO-B₂O₃-Na₂O system using the flux method. This compound crystallizes in the orthorhombic system, sp. gr. P2₁2₁2₁; the unit-cell parameters are a = 9.590(2) Å, b = 16.659(3) Å, c = 22.919(6) Å, and Z = 12. The structure consists of coordination polyhedra of barium cations and the anionic groups [BO₃] (planar triangles) and [B₂O₅] (vertex-sharing double [BO₃] triangles), which form a pseudohexagonal framework. Melting of barium borate occurs by a peritectic reaction at 1170 ± 10°C.     

Crystal structure of Co4(CO)10S2 and Co4(CO)10Se2; v(CO) vibrations of a model cluster molecule: Co4(CO)10S2

The crystal structure of Co₄(CO)₁₀S₂ has been redetermined and that of Co₄(CO)₁₀Se₂ obtained by X-ray analysis. The compounds are monoclinic and isomorphous, space groupP2₁/n,Z=2, with (S compound)a=10.42(2)Å,b=6.794(1)Å,c=12.421(2)Å,=97.27(1) and (Se compound)a=10.110(2)Å,b=6.747(2)Å,c=12.592(4)Å,=96.37(2); finalR(S)=0.029,R _w =0.032 for 1414 reflections and finalR (Se)=0.052,R _w =0.054 for 1264 reflections. The molecules, which lie on a crystallographic center of symmetry, consist of a rectangle with Co atoms at the corners, each face of the rectangle being capped by a chalcogen atom. Each Co atom is bonded to two terminal CO groups; there are two bridging CO groups, one on each member of a pair of opposite sides of the rectangle. The vibrational spectra of the sulfur compound are considered in detail. A study of the crystal structure, and recognition of an approximate spectroscopic space group, are shown to be essential for an understanding of thev(CO) infrared spectrum of polycrystalline Co₄(CO)₁₀S₂. In this molecule, intramolecular vibrational coupling in the crystal leads to extensive modifications of the infrared-activev(CO) molecular coordinates.     

Crystal structure of 2,3-bis(2-pyridyl)-5, 8-dimethoxyquinoxaline

Crystals of 2,3-bis(2-pyridyl)-5,8-dimethoxyquinoxaline (bpdmq) were examined using X-ray diffraction analysis: Monoclinic, space group P2 ₁/n with a = 6.9362(14) Å, b =17.285(4) Å, c =13.583(3) Å, =96.21(3)°, V =1619.0(6) ų, Z = 4. The crystal structure indicates that the title compound consists of quinoxaline ring system substituted with two pyridine rings and two methoxy groups. Two pyridine rings form dihedral angles of 39.8 and 44.1° with the mean planar quinoxaline ring, and a dihedral angle of 67.1° with each other. The orientation of the pyridine rings is such that their N atoms face each other. There exist significant – interactions responsible for the formation of the stacks along the a-axis of the crystal packing.     

Crystal and molecular structure of cyclo-bisoxalyldecasulfur S10(CO)4

Cyclo-bisoxalyldecasulfur, S₁₀(CO)₄, is monoclinic:P2₁/n,a = 7.812(2),b = 7.273(2),c = 12.570(7) Å, = 91.33 ° (4), andZ = 2. The structure was solved by direct methods from 942 nonequivalent four-circle diffractometer data and refined by least-squares methods toR(F) = 0.104 andR _w(F) = 0.065. The mean S-S distance is 2.051 Å. The molecule is stabilized by intramolecular contact distances shorter than the sum of the van der Waals radii. The two S-(C-O)-C groups are planar, with an angle of 15 ° between them.     

Crystal structure of dinitratotris(pyridine)nickel(II), Ni(NC5H5)3(NO3)2

Ni(NC₅H₅)₃(NO₃)₂ crystallizes in the triclinic space group P¯1 witha=8.432(2),b=9.993(2),c=12.181(3)Å, =69.78(2),=83.16(2), =67.73(1), andD _c =1.57 g cm^–3 forZ=2. The Ni²⁺ ion is six-coordinate with one bidentate and one monodentate nitrato ligand.     

Crystal structure of zdenekite NaPbCu5(AsO4)4Cl · 5H2O

The crystal structure of the mineral zdenekite NaPbCu₅(AsO₄)₄Cl · 5H₂O was established (Bruker SMART CCD diffractometer, synchrotron radiation, λ = 0.6843Å, R = 0.096 for 1356 reflections). Single-crystal X-ray diffraction study demonstrated that zdenekite belongs to the monoclinic system with the unit-cell parameters a = 10.023(7) Å, b = 19.55(1) Å, c = 10.023(6) Å, β = 90.02(1)°, sp. gr. P2₁/n, Z = 4. The structure consists of polyhedral layers parallel to the (010) plane. These layers are formed by Cu? polyhedra φ = O, Cl, H₂O) and AsO₄ tetrahedra. Distorted Na octahedra and Pb 7-vertex polyhedra and H₂O molecules coordinated to these metal atoms are located between the layers.     

Crystal structure of Pt(S2COEt)2

The crystals of Pt(S₂COEt)₂ are orthorhombic, Pbca, with (at 20°C)a=7.799(3),b=7.368(6),c=20.588(7) Å.D _cale=2.46g cm^–3 forZ=4. The platinum atom resides on a crystallographic center of inversion and is bound to the four sulfur atoms of the xanthato ligand in a square planar geometry. The Pt–S distances are 2.313(6) and 2.320(7)Å with an intraligand S–Pt–S angle of 75.1(2)°.     

Crystal structure analysis and refinement of Kalabsha kaolinite (Al2Si2O5(OH)4)

The crystal structure of the kaolinite mineral from Kalabsha, Aswan, Egypt, has been investigated with a two-step procedure of the X-ray powder pattern-fitting. The unit cell is found to be triclinic, P1, a = 5.1577(15), b = 8.9417(23), c = 7.3967(40) Å, α = 91.672(5)°, β = 104.860(2) and γ = 89.898(2)°. The refinements of the non-hydrogen atomic positions showed a reliability factors R_WB = 0.037 and R_B = 0.0417. The average rotation angle in the tetrahedral layer in 10°.     

Crystal structure of trans-C2SnO5 pentagonal bipyramidal dibutylbis(phenylacetato)tin(IV) hydrate

The Lewis acidity of tin in a diorganotin dicarboxylate is demonstrated in this first example of a 1/1 adduct of the ester with a neutral ligand. The structure of dibutyltin bisphenylacetate hydrate [(C₄H₉)₂Sn(O₂CCH₂C₆H₅)₂·H₂O] has been determined from 1211 F ₀6F _c MoK reflections and refined to anR _F of 0.061 [space groupP2/a witha=8.416(2),b=10.391(5),c=14.28(1) Å,=98.42(4)° andZ=2]. TheC atoms [Sn-C 2.101(8) Å; C-Sn-C 169.9(5)°] make up the apices and the O_carboxylate [Sn-O 2.234(5), 2.439(7) Å; O-Sn-O 55.7(2)°] and O_water [Sn-O 2.342(8) Å] atoms the equatorial points of thetrans-C₂SnO₅ pentagonal bipyramid around the Sn atom. The molecular symmetry isC ₂, and the Sn and O_water atoms lie along a crystallographic twofold axis. The aqua ligand forms donor H-bonds with neighboring carboxylato groups to link the molecules into a double zigzag chain running parallel toa.     

Crystal and molecular structure of (Z)-2-(1,3-benzothiazol-2-yl)-2-(6,7,8,9-tetrahydro-5H-benzocyclohepten-5-ylidene)ethanonitrile

The title compound C₂₀H₁₆N₂S is crystallized in the monoclinic space groupP2₁/c with cell parametersa=10.663(4),b=17.585(9),c=9.418(5)Å,=115.23°(4),V=1598(3)ų,Z=4. The structure was refined by full-matrix least-squares methods using X-ray data set collected at room temperature. A finalR _F =0.033 andR _w =0.048 for 2225 unique reflections withI> 3(I) and 272 variables was obtained. The X-ray crystallographic study establishes theZ stereochemistry of the title compound.     

Crystal structure of Pr2B5 boride

The crystal structure of Pr₂B₅ boride of a new type was established by single-crystal X-ray diffraction analysis; sp. gr. C2/c, a = 15.1603(4) Å, b = 7.2771(2) Å, c = 7.3137(2) Å, β = 109.607(2)°, 2068 reflections, R _F = 0.041, R _w = 0.055. The Pr₂B₅ structure is similar to the Gd₂B₅ structure.     

Crystal structure ofcis-diaqua bis(2,2′-bipyridyl)chromium(III) nitrate, [Cr(bipy)2(H2O)2] (NO3)3

cis-Diaquabis(2,2-bipyridyl)chromium(III) nitrate crystallizes in the mono-clinic system, space groupP2₁/c, witha=16.102(6),b=10.792(5),c=15.076(6) Å,=112.90(5)°, andZ=4. The saltlike structure was determined from X-ray crystallography and refined toR=7.5% for 3342 observed reflections. The Cr atom is octahedrally surrounded by twocis water molecules and by two chelated 2,2-bypiridyl ligands forming two nearly orthogonal planes. Selected bond distances are: Cr-O, 2.00(1) and 1.98(1) Å, Cr-N, 2.04 Å (mean).     

Crystal structure of Zn[Cl2Ti(C5H5)2]2·2C6H6

The structure of crystals of the composition Zn[Cl₂Ti(C₅H₅)₂]₂·2C₆H₆ has been determined from Patterson and Fourier syntheses of two projections, and refined toR = 0·117 by full-matrix three-dimensional least-squares methods. The crystals are orthorhombic:Pbcn,a = 18·45(5),b = 15·40(6),c = 11·35(3) Å,Z= 4. The complex consists of a central distorted ZnCl ₄ ^2– tetrahedron linked along the Cl—Cl edges to two distorted TiCl₂(C₅H₅)₂ ⁺ tetrahedra in such a way that their centres are nearly collinear The two C₆H₆ molecules in the formulae unit may be regarded as benzene of crystallization.