scholarly journals The crystal and molecular structure of NaBF3OH

1970 ◽  
Vol 48 (3) ◽  
pp. 405-409 ◽  
Author(s):  
M. J. R. Clark ◽  
H. Lynton
Keyword(s):  
Molecular Structure ◽  
Least Squares ◽  
Crystal And Molecular Structure ◽  
Hydroxyl Group ◽  
Hexagonal System ◽  
X Ray ◽  
Cell Parameters ◽  
Anisotropic Temperature ◽  
Final Agreement ◽  
Atomic Parameters

The crystal and molecular structure of sodium hydroxytrifluoborate, NaBF3OH, has been established by X-ray analysis. This compound crystallizes in the hexagonal system, space group P63 with cell parameters a = 8.084 Å and c = 7.958 Å. There are 6 molecules in the unit cell. Atomic parameters have been obtained from a block-diagonal least-squares refinement using anisotropic temperature parameters for boron and fluorine, and isotropic temperature parameters for sodium. The final agreement residual for 195 observed reflections is R = 0.090.The [BF3OH]− anions are distorted tetrahedra. It was not possible to distinguish between the positions of the fluorine atoms and the isoelectronic hydroxyl group.

Crystal and molecular structure of CuSiF6•4H2O

1969 ◽  
Vol 47 (20) ◽  
pp. 3859-3861 ◽  
Author(s):  
M. J. R. Clark ◽  
J. E. Fleming ◽  
H. Lynton
Keyword(s):  
Molecular Structure ◽  
Least Squares ◽  
Fluorine Atom ◽  
Crystal And Molecular Structure ◽  
Unit Cell ◽  
Space Group ◽  
Anisotropic Temperature ◽  
Cell Dimensions ◽  
Final Agreement ◽  
Atomic Parameters

The structure of CuSiF6•4H2O has been shown to consist of chains of [Cu(H2O)4F2] and [SiF6] octahedra linked through a common fluorine atom. The space group is monoclinic P21/a, with cell dimensions a = 7.22 ± 0.01 Å, b = 9.64 ± 0.01 Å, c = 5.36 ± 0.01 Å and β = 105.2 ± 0.3°. There are 2 molecules in the unit cell and the copper and silicon atoms occupy centers of symmetry. Atomic parameters have been obtained from a block diagonal least squares refinement using anisotropic temperature parameters. The final agreement residual for 574 observed reflections is R = 0.083.

The crystal and molecular structure of a 1:1 complex of 5-bromouridine and dimethylsulphoxide

1968 ◽  
Vol 302 (1469) ◽  
pp. 225-236 ◽  
Keyword(s):  
Molecular Structure ◽  
Hydrogen Bonds ◽  
Oxygen Atom ◽  
Diffraction Data ◽  
Crystal And Molecular Structure ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
X Ray ◽  
Cell Parameters ◽  
Anisotropic Temperature

A complex consisting of one molecule of 5-bromouridine ( BUR ) and one molecule of di­methylsulphoxide ( DMSO ) has been prepared in the form of monoclinic crystals. The unit cell parameters are as follows, a = 13⋅65 ± 0⋅01, b = 4.820 ± 0⋅005, c = 12⋅09 ± 0⋅01 Å, β = 91⋅8 ± 0.1°, space group P 2 1 . X-ray diffraction data ( ⋋ = 1⋅5418 Å) for 1389 independent reflexions were collected and the structure was determined from Patterson syntheses which gave the coordinates of the bromine and sulphur atoms. Fourier syntheses followed by least-squares refinement (including anisotropic temperature parameters) reduced the agreement index R to 0⋅067. The bond lengths and angles for each molecule are given, and it is shown that hydrogen bonds are formed between the oxygen atom of the DMSO molecule and the 03' and 05' of the BUR molecules. A comparison is made between the conformation of the BUR molecule in this complex and that of the same molecule in two other structures.

Crystal and molecular structure of the m-bromobenzoate derivative of bisnorquassin

1970 ◽  
Vol 48 (2) ◽  
pp. 307-311 ◽  
Author(s):  
H. Lynton
Keyword(s):  
Molecular Structure ◽  
Crystal And Molecular Structure ◽  
Heavy Atom ◽  
Unit Cell ◽  
Anisotropic Temperature ◽  
Cell Dimensions ◽  
Final Agreement ◽  
Unit Cell Dimensions ◽  
Heavy Atom Method ◽  
Atomic Parameters

The molecular structure of the m-bromobenzoate derivative of bisnorquassin, C27H27O7Br, has been determined by the heavy atom method. The compound crystallizes in the orthorhombic system, space group P212121, with unit cell dimensions a = 20.09 ± 0.02 Å, b = 14.63 ± 0.02 Å, c = 8.06 + 0.01 Å and 4 molecules in the unit cell. Final atomic parameters have been obtained from a blockdiagonal least-squares refinement using anisotropic temperature parameters. The final agreement residual for 1665 observed reflections is R = 0.107.The structure of bisnorquassin previously proposed by Findlay and Cropp, on the basis of spectroscopic and chemical evidence, is shown to be essentially correct.

Crystal and Molecular Structure of tetrakis(4-Methylpyridine)nickel(II)perchlorate, [Ni(II)(C6H7N)4][ClO4]2

1973 ◽  
Vol 51 (12) ◽  
pp. 1952-1958 ◽  
Author(s):  
N. Bose ◽  
H. Lynton
Keyword(s):  
Molecular Structure ◽  
Hydrogen Atom ◽  
Least Squares ◽  
Crystal And Molecular Structure ◽  
Nickel Atom ◽  
Monoclinic Space Group ◽  
Perchlorate Ion ◽  
Square Planar ◽  
Final Agreement ◽  
Atomic Parameters

Crystals of tetrakis(4-methylpyridine)nickel(II)perchlorate, Ni(C6H7N)4(ClO4)2, are monoclinic, space group C2/c, with a = 18.38(1), b = 10.71(1), c = 15.58(1) Ǻ, β = 109.83(5)°, and four molecules in the unit cell. The final atomic parameters were obtained from a block-diagonal least squares refinement using anisotropic thermal parameters. The hydrogen atom positions were established but the parameters were not refined. The final agreement residual for 1199 observed reflections is R = 0.049. The structure consists of discrete Ni(C6H7N)42+ and ClO4− groups. The perchlorate ion is disordered. The 4-methyl-pyridine rings are in a square planar arrangement about the nickel atom.

Crystal and Molecular Structure of Hexaaquocobalt(II)–Hexafluorosilicate(IV), [Co(H2O)6][SiF6]

1973 ◽  
Vol 51 (2) ◽  
pp. 227-229 ◽  
Author(s):  
H. Lynton ◽  
P-Y. Siew
Keyword(s):  
Molecular Structure ◽  
Hydrogen Atom ◽  
Hydrogen Bonds ◽  
Least Squares ◽  
Crystal And Molecular Structure ◽  
Heavy Atom ◽  
Thermal Parameters ◽  
Final Agreement ◽  
Heavy Atom Method ◽  
Atomic Parameters

The structure of hexaaquocobalt(II)-hexafluorosilicate(IV) has been determined by the heavy atom method. The compound crystallizes in the space group [Formula: see text], with three molecules in the hexagonal unit cell of dimensions a = 9.358(16), c = 9.712(14) Å. The atomic parameters were refined by block diagonal least squares using anisotropic thermal parameters. The hydrogen atom positions were established but the parameters were not refined. The final agreement residual for 151 observed reflections is R = 0.043.The structure consists of discrete Co(H2O)62+ and (SiF6)2− octahedra joined systematically by [Formula: see text] hydrogen bonds into chains parallel to the [Formula: see text] axis.

Crystal and Molecular Structure of Dichlorobis(4-methylpyridine)zinc(II), Zn(4-CH3Py)2Cl2

1971 ◽  
Vol 49 (21) ◽  
pp. 3418-3424 ◽  
Author(s):  
H. Lynton ◽  
M. C. Sears
Keyword(s):  
Molecular Structure ◽  
Hydrogen Atom ◽  
Least Squares ◽  
Crystal And Molecular Structure ◽  
Unit Cell ◽  
Thermal Parameters ◽  
Zinc Atom ◽  
Final Agreement ◽  
Atomic Parameters ◽  
Block Diagonal

Crystals of dichlorobis(4-methylpyridine)zinc(II), Zn(4-CH3Py)2Cl2, are monoclinic, space groupP21/c, with a = 14.294(13), b = 7.885(8), c = 13.473(11) Å, β = 100.60(5)° and 4 molecules in the unit cell. The final atomic parameters were obtained from a block-diagonal least squares refinement using anisotropic thermal parameters. The hydrogen atom positions were established but the parameters were not refined. The final agreement residual for 1348 observed reflections is R = 0.043. The zinc atom is tetrahedrally coordinated.

The crystal structure of dibutyl-bis(pentamethylenedithiocarbamato)tin(IV)

1986 ◽  
Vol 51 (11) ◽  
pp. 2521-2527 ◽  
Author(s):  
Jan Lokaj ◽  
Eleonóra Kellö ◽  
Viktor Kettmann ◽  
Viktor Vrábel ◽  
Vladimír Rattay
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Least Squares ◽  
Coordination Polyhedron ◽  
Crystal And Molecular Structure ◽  
Distorted Octahedron ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray

The crystal and molecular structure of SnBu2(pmdtc)2 has been solved by X-ray diffraction methods and refined by a block-diagonal least-squares procedure to R = 0.083 for 895 observed reflections. Monoclinic, space group C2, a = 19.893(6), b = 7.773(8), c = 12.947(8) . 10-10 m, β = 129.07(5)°, Z = 2, C20H38N2S4Sn. Measured and calculated densities are Dm = 1.38(2), Dc = 1.36 Mg m-3. Sn atom, placed on the twofold axes, is coordinated with four S atoms in the distances Sn-S 2.966(6) and 2.476(3) . 10-10 m. Coordination polyhedron is a strongly distorted octahedron. Ligand S2CN is planar.

Crystal and molecular structure of 3-ethyl-4-hydroxy-1,2,3(4H)-benzotriazine and 6-chloro-4-hydroxy-3-methyl-4-phenyl-1,2,3-benzotriazine

1985 ◽  
Vol 63 (3) ◽  
pp. 581-585 ◽  
Author(s):  
Kwong Khee Lai ◽  
Carl H. Schwalbe ◽  
Keith Vaughan ◽  
Ronald J. Lafrance ◽  
Clive D. Whiston
Keyword(s):  
Molecular Structure ◽  
Hydrogen Bonds ◽  
Least Squares ◽  
Least Squares Method ◽  
Crystal And Molecular Structure ◽  
Tetrahedral Geometry ◽  
Orthorhombic System ◽  
Full Matrix ◽  
X Ray ◽  
R Factor

The crystal structures of the title compounds have been determined from X-ray data collected on a four-circle diffractometer and refined by the full-matrix least-squares method. The former compound crystallizes in the orthorhombic system, space group Pbcn, with a = 14.346(8), b = 7.239(1), c = 17.276(2) Å, and has been refined to a conventional R factor of 0.043 for 890 observed reflections. Corresponding results for the latter compound are monoclinic, P21/n, a = 12.222(4), b = 7.482(2), c = 14.170(8) Å, β = 94.06(4)°, R = 0.060 for 2128 observed data. The triazine rings of both compounds exhibit short N(1)—N(2) bonds and tetrahedral geometry at C(4); however, the ring is puckered in the first compound but flat in the second. Molecules in both crystals are linked by [Formula: see text] hydrogen bonds.

Crystal and Molecular Structure of Dithiocyanato(triphenylarsine)mercury(II)

1975 ◽  
Vol 53 (22) ◽  
pp. 3383-3387 ◽  
Author(s):  
Joseph Hubert ◽  
André L. Beauchamp ◽  
Roland Rivest
Keyword(s):  
Molecular Structure ◽  
Least Squares ◽  
Coordination Number ◽  
Diffraction Data ◽  
Crystal And Molecular Structure ◽  
Heavy Atom ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
X Ray ◽  
Heavy Atom Method

The crystal and molecular structure of dithiocyanato(triphenylarsine)mercury(II) has been determined from X-ray diffraction data. The crystals are monoclinic, space group P21/c, with a = 10.290(7), b = 21.199(23), c = 10.719(7) Å, β = 112.00(2)°, and Z = 4. The structure has been solved by the heavy-atom method and refined by block-diagonal least-squares calculations. The agreement factor R obtained for 2607 'observed' reflections is 0.030. The crystal consists of single molecules. The 'characteristic' coordination number of mercury is three, with two sulfur and one arsenic atoms at the apexes of a triangle. The nitrogen atoms of the thiocyanate groups are at 2.67 and 2.74 Å from the adjoining mercury atoms and therefore link the different molecules together.

Structural studies of organoboron compounds. LX. Reaction of sterically hindered arylboronic acids with 2-(hydroxyamino)alkanols. Crystal and molecular structure of 2-mesityl-6,6-pentamethylene-1,3-dioxa-4-aza-2-boracyclohexane

1994 ◽  
Vol 72 (4) ◽  
pp. 1154-1161 ◽  
Author(s):  
Wolfgang Kliegel ◽  
Gottfried Lubkowitz ◽  
Steven J. Rettig ◽  
James Trotter
Keyword(s):  
Molecular Structure ◽  
Least Squares ◽  
Crystal And Molecular Structure ◽  
Direct Methods ◽  
Structural Studies ◽  
Full Matrix ◽  
Space Group ◽  
X Ray ◽  
Arylboronic Acids ◽  
Sterically Hindered

Three 2-(hydroxyamino)alkanols have been reacted with sterically hindered arylboronic acids, ArB(OH)2. When Ar = o-tolyl, 1:2 condensates having bicyclic structures are formed but when Ar = mesityl (2,4,6-(CH3)3C6H2), 1:1 condensates having six-membered cycloboronate structures result. These 1:1 condensates represent the first examples of N-unsubstituted 1,3-dioxa-4-aza-2-boracyclohexane derivatives. An X-ray analysis of one example provides unambiguous proof of the structure. Crystals of 2-mesityl-6,6-pentamethylene-1,3-dioxa-4-aza-2-boracyclohexane, 3c, are monoclinic, a = 11.076(9), b = 23.94(2), c = 13.414(9) Å, β = 109.40(5)°, Z = 8, space group P21/n. The structure was solved by direct methods and refined by full-matrix least-squares procedures to R = 0.051 and Rw = 0.058 for 2037 reflections with I ≥ 3σ(F2).

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