Die Kristallstruktur des Trichlorphons C4H8O4PCl3

1969 ◽  
Vol 24 (9) ◽  
pp. 1071-1074 ◽  
Author(s):  
E. Höhne ◽  
Kh. Lohs
Keyword(s):  
Crystal Structure ◽  
Least Squares ◽  
Least Squares Method ◽  
Unit Cell ◽  
Fourier Methods ◽  
Space Group ◽  
R Factor ◽  
Anisotropic Temperature ◽  
Temperature Factors ◽  
Atomic Coordinates

The crystal structure of trichlorphon [O,O-Dimethyl- (1-hydroxy-2,2,2-trichlor-äthyl) -phosphonat] has been determined by PATTERSON and FOURIER methods. Space group P212121 with 4 molecules in a unit cell of dimensions α = 8,96 ± 0,03 A, b= 18,60 ± 0,05 Å, c = 5,80 ± 0,02 A were determined. Atomic coordinates and anisotropic temperature factors have been refined by the least squares method. The final R-factor is R (hkl) =0,102.

Crystal structure of KCaF3 determined by the Rietveld profile method

1997 ◽  
Vol 12 (2) ◽  
pp. 70-75 ◽  
Author(s):  
Alicja Ratuszna ◽  
Michel Rousseau ◽  
Philippe Daniel
Keyword(s):  
Crystal Structure ◽  
Room Temperature ◽  
Lattice Parameters ◽  
Profile Method ◽  
Anisotropic Temperature ◽  
Monoclinic Distortion ◽  
Refinement Procedure ◽  
Watson Statistic ◽  
Temperature Factors ◽  
Atomic Coordinates

Using the Rietveld profile method, the atomic coordinates and anisotropic temperature factors of KCaF3 were refined. At room temperature, KCaF3 crystallizes in monoclinic B21/m symmetry, with the lattice parameters: a=8.754(2) Å, b=8.765(4) Å, c=8.760(5) Å, β=90.48(3)°, V=672.1(3) Å3, Z=8. The refinement procedure was stopped when RB=0.05 and the Durbin–Watson statistic factor=0.85 had been reached. The structure determined is related to the tilting of CaF6 octahedra of the a−b+c− type, which are responsible for the monoclinic distortion in perovskite crystals.

The crystal structure of diamminesilver dinitroargentate, [Ag(NH3)2]Ag(NO2)2*

1977 ◽  
Vol 146 (4-6) ◽  
Author(s):  
H. M. Maurer ◽  
Alarich Weiss
Keyword(s):  
Crystal Structure ◽  
Least Squares ◽  
Heavy Atom ◽  
Anisotropic Temperature ◽  
Light Atoms ◽  
Difference Fourier ◽  
Temperature Factors ◽  
Heavy Atom Method ◽  
Silver Atoms ◽  
Block Diagonal

AbstractThe crystal structure of diamminesilver dinitroargentate, [Ag(NHThe point positions of the silver atoms were obtained by the heavy-atom method whereas those of the light atoms were found by difference Fourier syntheses. Coordinates and anisotropic temperature factors were refined by block-diagonal least-squares methods with the result

The crystal structure of kogarkoite, Na3SO4F

1980 ◽  
Vol 43 (330) ◽  
pp. 753-759 ◽  
Author(s):  
L. Fanfani ◽  
G. Giuseppetti ◽  
C. Tadini ◽  
P. F. Zanazzi
Keyword(s):  
Crystal Structure ◽  
Least Squares ◽  
Least Squares Method ◽  
Thermal Parameters ◽  
Cell Content ◽  
Space Group ◽  
X Ray ◽  
Structural Relationships ◽  
Automatic Diffractometer ◽  
Monoclinic Cell

SummaryThe crystal structure of synthetic kogarkoite has been determined from X-ray data collected on an automatic diffractometer. The refinement was performed by a least-squares method employing anisotropic thermal parameters. The 3157 reflections with I > 3σ(I) converged to a conventional R value of 0.033. The cell content is 12 Na3SO4F, the space-group P21/m, a = 18.074, b = 6.958, c = 11.443 Å, β = 107.71°.Kogarkoite presents a marked trigonal subcell with c′ corresponding to [102] of the monoclinic cell. The tridimensional framework can be considered built up by nine differently stacked layers of Na atoms approximately perpendicular to the c′ axis (five sheets are present in galeite, six in sulphohalite, and seven in schairerite). The very close structural relationships between these minerals are discussed.

Refinement of the structure of Mg2As2O7

1970 ◽  
Vol 48 (6) ◽  
pp. 890-894 ◽  
Author(s):  
C. Calvo ◽  
K. Neelakantan
Keyword(s):  
Crystal Structure ◽  
Oxygen Atom ◽  
Least Squares ◽  
Unit Cell ◽  
Full Matrix ◽  
Space Group ◽  
Cell Dimensions ◽  
Central Oxygen ◽  
R Value ◽  
Unit Cell Dimensions

The crystal structure of Mg2As2O7 has been refined by full matrix least squares procedures using 587 observed reflections. The structure of Mg2As2O7 is of the thortveitite type, as reported by Łukaszewicz, with space group C2/m and unit cell dimensions a = 6.567(2) Å, b = 8.524(4) Å, c = 4.739(1) Å, β = 103.8(1)°, and Z = 2. The As—O—As group in the anion appears to be linear but the central oxygen atom undergoes considerable disorder in the plane perpendicular to this group. The AsO bond distances uncorrected for thermal motion are 1.67 Å for the As—O(—As) bond and 1.66 and 1.65 Å for the terminal As—O bonds. The final R value obtained is 0.088.

The crystal structure of nickel(II) dimethyldithiocarbamate

1980 ◽  
Vol 45 (8) ◽  
pp. 2147-2151 ◽  
Author(s):  
Jan Lokaj ◽  
Ján Garaj ◽  
Viktor Kettmann ◽  
Viktor Vrábel
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Structural Analysis ◽  
Least Squares ◽  
Least Squares Method ◽  
Crystal And Molecular Structure ◽  
Unit Cell ◽  
Special Position ◽  
X Ray ◽  
Triclinic Unit Cell

Crystal and molecular structure of nickel(II) dimethyldithiocarbamate, Ni[S2CN(CH3)2]2 was solved by X-ray structural analysis and refined by the least squares method to R = 0.06 for 1065 reflections. The compound crystallizes in a space group P I and the triclinic unit cell has the dimensions: a = 6.521 (7), b = 6.798 (9), c = 7.633 (4), α = 67.21 (8)°, β = 67.34 (6)° γ =85.59 (9)°. The experimentally observed density is 1.75 g cm-3 and the calculated value for Z = 1 is 1.73 g cm-3. In the structure , the Ni atom occupies a special position in the centre of symmetry and is coordinated by four sulphur atoms in a plane: Ni-S 0.2218 (4) and 0.2198 nm S1-Ni-S2 angle 79.62 (8)°. The ligand S2CNC2 is nearly planar.

Reactions between Co(II), 1,2-bis(diphenylphosphino)ethane, and NaBH3CN in the presence and absence of CO. The crystal structure of bis(cyanotrihydroborato)tetrakis(N,N-dimethylformamide)cobalt(II)

1988 ◽  
Vol 66 (7) ◽  
pp. 1770-1775 ◽  
Author(s):  
David J. Elliot ◽  
Sanna Haukilahti ◽  
David G. Holah ◽  
Alan N. Hughes ◽  
Stanislaw Maciaszek ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Unit Cell ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
Triclinic Space Group ◽  
Space Group ◽  
X Ray ◽  
Cell Parameters ◽  
R Factor

Reactions between Co(II), Diphos, and NaBH3CN lead to Co(BH3CN)2(Diphos)2, 1, or [Co(BH3CN)(Diphos)2]X, 2 (X = ClO4 or BPh4), and, in certain solvents, 2 reacts to produce [Co(CN)(Diphos)2](ClO4). Compound 1 can be reversibly converted to Co(BH3CN)2(DMF)4, 4, via Co(BH3CN)2(Diphos)(DMF). In addition, 1 reacts with CO to form the Co(I) and Co(III) compounds [Co(Diphos)2](CO)]X and [Co(Diphos)2(CN)2]X (X = BH3CN or BPh4). Single crystal X-ray diffraction studies of 4 show that the compound crystallizes in the triclinic space group [Formula: see text], with unit cell parameters a = 7.572(6), b = 9.695(6), c = 9.395(6) Å, α = 81.06(4), β = 68.46(5), γ = 68.19(5)°, V = 595.5 Å3, Z = 1, and dcalcd = 1.202 g cm−3. The structure converged to a conventional R factor of 0.040 for 2841 observations and showed an octahedral arrangement of four O atoms from DMF molecules and two trans N-bound BH3CN groups around the Co(II) center.

Verfeinerung der Kristallstruktur eines basaltischen Magnesio-Hastingsites

1981 ◽  
Vol 156 (3-4) ◽  
Author(s):  
E. M. Walitzi ◽  
F. Walter
Keyword(s):  
Crystal Structure ◽  
Least Squares ◽  
Least Squares Method ◽  
Three Dimensional ◽  
Full Matrix ◽  
Space Group ◽  
X Ray

AbstractThe crystal structure of the basaltic clino-amphibole magnesio-hastingsite was refined from three-dimensional photographic X-ray data by a full matrix least-squares method in the space group

Crystal structure of triclinic rubidium dichromate, Rb2Cr2O7

1970 ◽  
Vol 48 (4) ◽  
pp. 537-543 ◽  
Author(s):  
N. Ch. Panagiotopoulos ◽  
I. D. Brown
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Least Squares ◽  
Unit Cell ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
Dichromate Ions ◽  
Oxygen Atoms

The crystal structure of triclinic rubidium dichromate has been determined by single crystal X-ray diffraction. The crystal belongs to space group [Formula: see text] with a = 13.554, b = 7.640, c = 7.735 Å, α = 93.64°, β = 98.52°, γ = 88.80° and has four Rb2Cr2O7 units in the unit cell. The final weighted agreement index after refinement by least-squares analysis is 0.058. The configuration of the dichromate ions is similar to that found in most other dichromate structures (Cr—O (bridging) = 1.78 Å, Cr—O (terminal) = 1.62 Å). The two non-equivalent Cr—O—Cr angles are 123 and 137°. The rubidium ions are surrounded by either 8 or 9 oxygen atoms at distances ranging from 2.86 to 3.31 Å. The structure of triclinic Rb2Cr2O7 is similar, but not identical, to that of triclinic K2Cr2O7.

Refinement of the Crystal Structure of the Low-quartz Modification of Ferric Phosphate

1975 ◽  
Vol 53 (14) ◽  
pp. 2064-2067 ◽  
Author(s):  
Hok Nam Ng ◽  
Crispin Calvo
Keyword(s):  
Crystal Structure ◽  
Least Squares ◽  
Room Temperature ◽  
Unit Cell ◽  
Full Matrix ◽  
Space Group ◽  
Ferric Phosphate ◽  
R Value

The structure of ferric phosphate at room temperature was refined on a Dauphiné-twinned crystal using full-matrix least-squares methods. The final R value was 0.078 for 487 symmetry-independent reflections whose intensities were corrected for twinning. The structure was found to be isotypic with AlPO4 (berlinite) with the space group P3121 and four formula units in a unit cell defined by a = 5.036(2) and c = 11.255(4) Å. The structure is also closely related to that of α-quartz with a nearly doubled c-axis because of the ordering of Fe and P atoms. The PO4 tetrahedron is almost regular with a mean P—O distance of 1.526 Å. The Fe3+ ion is tetrahedrally coordinated with an average Fe—O distance of 1.853 Å.

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.

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