The Structure of (NO)2[Ho(NO3)5], A 10-Coordinate Species

1975 ◽  
Vol 53 (6) ◽  
pp. 831-835 ◽  
Author(s):  
Gerald E. Toogood ◽  
Chung Chieh
Keyword(s):  
Ethyl Acetate ◽  
Heavy Atom ◽  
Full Matrix ◽  
Trigonal Bipyramidal ◽  
Anhydrous Ethyl Acetate ◽  
Dinitrogen Tetroxide ◽  
Stretching Vibration ◽  
The Mean ◽  
R Value ◽  
Heavy Atom Method

Nitrosonium pentanitratoholmate(III), (NO)2Ho(NO3)5, was prepared from holmium metal and dinitrogen tetroxide in anhydrous ethyl acetate. Its crystals are monoclinic with a = 8.094, b = 11.979, c = 14.170 Å and β = 104.7°,Z = 4, space group P21/c. The structure was solved by the heavy-atom method and refined by full matrix least-squares methods to an R value of 0.085 for 1514 observed reflections measured on the G.E. XRD-6 diffractometer. The structure consists of one Ho(NO3)52− and two NO+ ions. The holmium is 10-coordinated by five essentially symmetric bidentate nitrate groups which arrange themselves in a trigonal bipyramidal fashion around the metal with a mean Ho—O distance of 2.45 Å. The two NO+ ions per metal occupy slightly different environments and give rise to two i.r. bands at 2250 and 2285 cm−1, attributable to the (N, O+) stretching vibration. The mean N—O distance within these ions is 1.00 Å.

scholarly journals The crystal and molecular structure of the bis(N,N,N′,N′-tetramethylethanediamine) adduct of I(Br)InInBr2, In2Br3I•2C6H16N2, an indium–indium bonded molecule

1984 ◽  
Vol 62 (3) ◽  
pp. 601-605 ◽  
Author(s):  
Masood A. Khan ◽  
Clovis Peppe ◽  
Dennis G. Tuck
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Crystal And Molecular Structure ◽  
Heavy Atom ◽  
Orthorhombic Space Group ◽  
Trigonal Bipyramidal ◽  
Cell Dimensions ◽  
Unit Cell Dimensions ◽  
Heavy Atom Method ◽  
Distorted Trigonal Bipyramidal

The crystal structure of the title compound has been determined by the heavy atom method. The crystals are orthorhombic, space group Pbca, with unit cell dimensions a = 22.795(3) Å, b = 17.518(2) Å, c = 12.396(3) Å, Z = 8; R = 0.0409 for 1527 unique "observed" reflections. The structure is disordered, with each halogen site (X) occupied by 75% Br, 25% I. The molecule consists of two X2(tmen)In units (tmen = N,N,N′,N′-tetramethylethanediamine) with distorted trigonal bipyramidal geometry, joined by an In—In bond 2.775(2) Å in length.

The crystal and molecular structure of bis(ethylenediamine) copper(II) selenocyanate

1983 ◽  
Vol 48 (10) ◽  
pp. 2893-2902 ◽  
Author(s):  
Viktor Vrábel ◽  
Jan Lokaj ◽  
Ján Garaj
Keyword(s):  
Least Squares Method ◽  
Crystal And Molecular Structure ◽  
Heavy Atom ◽  
Selenium Atom ◽  
Special Position ◽  
Full Matrix ◽  
A Value ◽  
Square Planar ◽  
Heavy Atom Method ◽  
Coordination Plane

The crystal structure of [Cu(en)2](SeCN)2 was solved by the heavy atom method and refined by the least squares method using the full matrix and anisotropic thermal parameters to a value of R = 0.063 for 660 observed reflections. The crystals are triclinic , with a space group of P1 and lattice parameters of a = 6.660(2), b = 9.360(2), c = 7.754(2) . 10-10 m, α = 129.22(2), β = 109.87(2) and γ = 92.38(2)°, Z = 1. The structure consists of discrete molecules that are centrosymmetric. The Cu(II) atom occupies a special position at the centre of symmetry and is coordinated by 4 nitrogen atoms from two bidentate ethylenediamine molecules: C-N 1.999(8) and 2.033(8) . 10-10 m and angle N1-Cu-N2, 84.1(3)°. The selenium atom in the SeCN group completes this square planar arrangement to form a deformed octahedron along the longer Cu...Se distance of 3.263(2) . 10-10 m. The ethylenediamine molecule has a non-symmetrical gauche arrangement with the carbon atoms C1 and C2 + 0.542 and -0.095 . 10-10 m above and below the N1-Cu-N2 coordination plane, respectively.

Studies on tellurium-carbon bonded compounds. II. The crystal structure of [Heptane-3,5-dionato(2 - )]tellurium(II) ('1,1′-Dimethylacetylacetone tellurium(II)')

1977 ◽  
Vol 30 (3) ◽  
pp. 487 ◽  
Author(s):  
JC Dewan ◽  
J Silver
Keyword(s):  
Crystal Structure ◽  
Least Squares ◽  
Title Compound ◽  
Heavy Atom ◽  
Chair Conformation ◽  
Heterocyclic Ring ◽  
Monoclinic Space Group ◽  
Hydrogen Atoms ◽  
Full Matrix ◽  
Heavy Atom Method

The structure of the title compound has been determined by the heavy- atom method from 973 reflections, measured with a diffractometer, and refined by full-matrix least-squares methods to R 0.030. Crystals are monoclinic, space group P21, a = 8.69(1), b = 4.86(1), c = 10.14(2) Ǻ, β = 98.7(1)�, Z = 2. In the discrete molecules of the complex a tellurium(II) atom is bonded to one bivalent heptane-3,5-dione ligand through the α-carbon atoms [Te-C 2.184(6), 2.206(7) Ǻ; C-Te-C 89.7(3)�], forming a heterocyclic ring of chair conformation with the methyl substituents both in equatorial positions. The molecules are arranged in a zig-zag polymeric manner about the 21 axes at x = 0 and z = 0. All hydrogen atoms have been located.

The Crystal Structure of KAlP2O7

1973 ◽  
Vol 51 (16) ◽  
pp. 2613-2620 ◽  
Author(s):  
Hok Nam Ng ◽  
Crispin Calvo
Keyword(s):  
Crystal Structure ◽  
Spherical Shell ◽  
Bond Length ◽  
Least Squares ◽  
Least Squares Method ◽  
Full Matrix ◽  
Bond Lengths ◽  
The Mean ◽  
R Value ◽  
Oxygen Atoms

KAlP2O7 crystallizes as monoclinic crystals with a = 7.308(8), b = 9.662(6), c = 8.025(4) Å, β = 106.69(7)°, z = 4 and space group P21/c. The structure was refined from 1394 observed reflections by full-matrix least-squares method to a final R value of 0.032. The P2O74− anion consists of a pair of corner-sharing PO4 groups in a nearly staggered configuration. The mean bridging and terminal P—O bond lengths are 1.607 and 1.509 Å, respectively, and the P—O—P angle is 123.2°. The anions lie in planes parallel to (001). The Al ions are bonded to six oxygen atoms contributed by anions in three layers of P2O7 groups. The average Al—O bond length is 1.889 Å. The potassium ion is coordinated to ten oxygen atoms lying within a spherical shell with inner and outer radii of 2.739 and 3.185 Å.

Chemistry of proximal π-bond systems. Part IV. The structure of 5,6-dimethylenebicyclo[2,2,1]hept-2-ene molybdenum tricarbonyl

1976 ◽  
Vol 54 (12) ◽  
pp. 1958-1966 ◽  
Author(s):  
Bryan F. Anderson ◽  
Glen B. Robertson ◽  
Douglas N. Butler
Keyword(s):  
Metal Atom ◽  
Heavy Atom ◽  
Least Square ◽  
Molybdenum Atom ◽  
Full Matrix ◽  
Space Group ◽  
Bond Lengths ◽  
R Factor ◽  
Heavy Atom Method

Crystals of 5,6-dimethylenebicyclo[2,2,1]hept-2-ene molybdenum tricarbonyl 1 (M = Mo) are monoclinic, a = 7.4451(3) Å, b = 13.5783(7) Å, c = 11.2691(4) Å, β = 92.593(3)°, Z = 4, space group P21/c. The structure was solved by the 'heavy atom' method and was refined by full-matrix least square procedures to a final R = 0.031. The weighted R factor was 0.051. Experimental bond lengths and angles are close to other reported values for bicyclo[2,2,1]hept-2-ene systems except for three major distortions in the triene ligand namely: the closing of the angles C(2)—C(1)—C(6) and C(3)—C(4)—C(5) by about 5.3°, the bending of the butadiene fragment plane C(8)—C(5)—C(6)—C(9) toward the metal atom by about 20° and the twisting of the terminal methylene hydrogens H(8i) and H(9i) out of the butadiene fragment plane (0.44 and 0.53 Å respectively) away from the molybdenum atom.

Crystallographic Studies of Cobalt Arsenate. III. Crystal Structure of Co6.95As3.62O16

1974 ◽  
Vol 52 (1) ◽  
pp. 46-50 ◽  
Author(s):  
Narasimhan Krishnamachari ◽  
Crispin Calvo
Keyword(s):  
Population Analysis ◽  
Inversion Symmetry ◽  
Unit Cell Parameters ◽  
Full Matrix ◽  
Cell Parameters ◽  
Bond Lengths ◽  
The Mean ◽  
R Value ◽  
Cation Sites ◽  
Site Population

Crystals of Co7.0As3.6O16 (1.8 × 3.84 CoO.As2O5) are orthorhombic with unit cell parameters a = 10.526(5), b = 5.985(2), and c = 4.871(2) Å. The space group is Pnma with Z = 1 and, except for fractionally occupied cation sites, the crystals have a structure closely related to that of the mineral olivine. The structure was refined by full-matrix least-squares with isotropic thermal parameters, using 1175 independent reflections measured with MoKα radiation, to a final R value of 0.075. The composition was determined by site population analysis. The structure is based upon a hexagonally close-packed arrangement of oxygen layers with As in tetrahedrally and Co in octahedrally coordinated interstices. The mean As—O bond length is 1.676 Å and the mean Co—O bond lengths are 2.139 Å for the site with m symmetry and 2.174 Å for the site showing inversion symmetry. These bond lengths are uncorrected for the effects of fractional occupancy of some of the cation sites.

Crystal and Molecular Structure of the N-Methyldiethanolaminogallane Dimer, [CH3N(CH2CH2O)2GaH]2

1974 ◽  
Vol 52 (12) ◽  
pp. 2206-2215 ◽  
Author(s):  
Steven J. Rettig ◽  
Alan Storr ◽  
James Trotter
Keyword(s):  
Molecular Structure ◽  
Hydrogen Bonds ◽  
Experimental Error ◽  
Crystal And Molecular Structure ◽  
Fourier Synthesis ◽  
Full Matrix ◽  
Axial Ligands ◽  
Trigonal Bipyramidal ◽  
The Mean ◽  
Distorted Trigonal Bipyramidal

Crystals of the N-methyldiethanolaminogallane dimer are orthorhombic, a = 19.112(4), b = 9.947(2), c = 7.709(2) Å, Z = 4, space group P212121. The structure was determined by Patterson and Fourier synthesis and was refined by full-matrix least-squares procedures to a final R of 0.056 for 1477 observed reflections. The structure provides the first1 known crystallographic example of pentacoordinate gallium, the dimerization of MeN(CH2CH2O)2GaH occurring via the formation of a four-membered Ga2O2 ring. The coordination about the gallium is distorted trigonal bipyramidal with an angle of 151.2(4)° between the axial substituents. The mean bond distances are: Ga—N, 2.192(5), and Ga—O, 2.018(2) for axial ligands; Ga—O, 1.847(2), 1.960(8), and Ga—H, 1.41(4) for equatorial ligands; O—C, 1.419(14), C—N, 1.470(7), C—C, 1.520(12), and C—H, 1.00(13) Å. The molecule has C2 symmetry to within experimental error. There are possible [Formula: see text] hydrogen bonds ([Formula: see text] 3.13(1)–3.44(1) Å) in the structure.

Crystal and Molecular Structure of the Synthetic Intermediate, 2-Bromo-3-methoxy-5-hydroxy-5,6,7,8,9,10,13,14-octahydro-8-methyl-10,13-N-acetylaminomethano-phenanthrene, C19H24O3NBr

1973 ◽  
Vol 51 (16) ◽  
pp. 2637-2638 ◽  
Author(s):  
H. Lynton ◽  
P. Y. Siew
Keyword(s):  
Crystal And Molecular Structure ◽  
Heavy Atom ◽  
Monoclinic Space Group ◽  
Asymmetric Unit ◽  
Full Matrix ◽  
Cell Dimensions ◽  
Ring Nitrogen ◽  
Unit Cell Dimensions ◽  
Synthetic Intermediate ◽  
Heavy Atom Method

Crystals of the synthetic intermediate, 2-bromo-3-methoxy-5-hydroxy-5,6,7,8,9,10,13,14-octahydro-8-methyl-10,13-N-acetyl aminomethano-phenanthrene, C19H24O3NBr, are monoclinic, space group P21/n, unit cell dimensions a = 10.62(1), b = 14.47(2), c = 23.88(2) Å, β = 99.4(2)°, z = 8 with two molecules in the asymmetric unit. The structure was solved by the heavy atom method and refined by full matrix least squares to R = 0.096 for 2120 observed reflections. The conformation was found to be cis at the junction between rings A and B making further cyclization to obtain an A ring nitrogen bridge not possible.

The Stereochemistry of Some Organic Derivatives of Group Vb Elements. Part X. The Crystal and Molecular Structure of Triphenylarsenic Difluoride

1975 ◽  
Vol 53 (11) ◽  
pp. 1647-1650 ◽  
Author(s):  
Ann Augustine ◽  
George Ferguson ◽  
Frank C. March
Keyword(s):  
Crystal And Molecular Structure ◽  
Heavy Atom ◽  
Three Dimensional ◽  
Arsenic Atom ◽  
Orthorhombic Space Group ◽  
X Ray ◽  
Trigonal Bipyramidal ◽  
Phenyl Rings ◽  
Derivatives Of ◽  
Heavy Atom Method

The crystal structure of triphenylarsenic difluoride has been determined from three-dimensional X-ray diffractometer data. Crystals of Ph3AsF2 are orthorhombic, space group Pbcn, with four molecules of C18H15AsF2 in a unit cell of dimensions a = 6.270, b = 16.593, c = 14.519 Å; molecular symmetry C2 is required. The structure was solved by the heavy atom method and refined by full-matrix least-squares calculations to a final residual R of 0.054 for 979 intensities regarded as "observed" (I > 3σ(I)). The crystals contain well separated discrete molecules. The arsenic atom has near regular trigonal bipyramidal geometry with apical fluorine atoms (As—F 1.834(7) Å) and equatorial phenyl rings (mean As—C 1.925(5) Å). Idealized D3 symmetry is not achieved because of unequal rotations of the phenyl rings about the As—C bonds.

Crystal and Molecular Structure of Triaqua-tri-μ-chloro-hexachloro-triangulo-trirhenium(III)-Bis[4,6-dimetylpyrimidine-2(1H)-thione hydrochloride]-Dihydrate

1987 ◽  
Vol 40 (12) ◽  
pp. 2123 ◽  
Author(s):  
LP Battaglia ◽  
AB Corradi ◽  
R Battistuzzi ◽  
T Manfredini
Keyword(s):  
Organic Molecules ◽  
Crystal And Molecular Structure ◽  
Heavy Atom ◽  
Chloride Ions ◽  
Water Molecules ◽  
Orthorhombic Space Group ◽  
Chlorine Atoms ◽  
Cell Dimensions ◽  
R Value ◽  
Heavy Atom Method

Reaction between rhenium(III) chloride and 4,6-dimethylpyrimidine-2(1H)- thione hydrochloride in concentrated HCl solution results in the formation of [Re3C19(H2O)3].2(C6H7N2S.HCl).-2H2O. The compound crystallizes in the orthorhombic space group Pnma with cell dimensions a 16.797(4), b 21.917(4), c 9.514(1) � and Z 4. The structure was solved by the heavy-atom method and refined by least-squares calculations to a final R value of 0.0517 (R' 0.0602). The structure consists of discrete [Re3Cl9(H2O)3] units, protonated organic molecules, chloride ions, and water molecules. In the cluster three rhenium atoms are linked to form a triangle, with chlorine atoms bridging each pair of rheniums which present short Re-Re bonds [2.440(1), 2.433(1) and 2.444(1) �]. Three water molecules in the equatorial plane and six chlorine atoms perpendicular to it (three above and three below) make the coordination around each rhenium distorted pentagonal bipyramidal.

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