Refinement of the crystal structure of metatorbernite

1993 ◽  
Vol 205 (1) ◽  
pp. 1-7 ◽  
Author(s):  
A. C. Stergiou ◽  
P. J. Rentzeperis ◽  
S. Sklavounos
Keyword(s):  
Crystal Structure ◽  
Least Squares ◽  
Anomalous Dispersion ◽  
Thermal Parameters ◽  
Water Molecules ◽  
Full Matrix ◽  
Absorption Correction ◽  
Atom Position ◽  
Oxygen Atoms

AbstractThe crystal structure of metatorbernite with composition CuThe positional and thermal parameters were refined by full-matrix least-squares calculations. Absorption correction and correction for anomalous dispersion, for all atoms, were applied. The finalThe structure is essentially similar to that described by M. Ross, H. Evans and D. Appleman (1964) for metatorbernite, with a difference in the Cu atom position, which here is 1/4 1/4 0.31 instead of 1/4 1/4 0.80. The U atoms are six-coordinated by two O atoms (uranyl group) and four phosphate – oxygen atoms forming an asymmetrical tetragonal dipyramid. The Cu atoms are six-coordinated by two oxygen atoms of two different uranyl groups and four water molecules forming also an asymmetrical tetragonal dipyramid. The four water molecules form squares Cu(H

The crystal structure of arsenic telluroxide AsTe0.5O2

1993 ◽  
Vol 205 (1) ◽  
Author(s):  
A. C. Stergiou
Keyword(s):  
Crystal Structure ◽  
Least Squares ◽  
Single Crystals ◽  
Direct Methods ◽  
Anomalous Dispersion ◽  
Thermal Parameters ◽  
Trigonal Prism ◽  
Population Parameter ◽  
Full Matrix

AbstractSingle crystals of AsTeSolution of the structure was essentialy effected by direct methods combined with successive Fourier syntheses. The positional and anisotropic thermal parameters were refined by full-matrix least-squares calculations. Absorption and anomalous dispersion corrections were applied to all atoms. The finalThe As atom is coordinated by six O atoms forming a right trigonal prism. The Te atom site is partially occupied by Te atoms with a population parameter 0.5 and surrounded by six O atoms also forming a right trigonal prism. The structure looks like that of NiAs. Each of the AsO

The crystal structure of epistilbite

1967 ◽  
Vol 36 (280) ◽  
pp. 480-490 ◽  
Author(s):  
A. J. Perrotta
Keyword(s):  
Crystal Structure ◽  
Least Squares ◽  
Water Molecules ◽  
Alumino Silicate ◽  
Silicate Framework ◽  
Oxygen Atoms

SummaryThe crystal structure of epistilbite ((Ca2·59Na1·06K0·10) (Al6·29Si17·71O48).15·74H2O; C2/m; a = 9·08, b = 17·74, c = 10·25±0·01 Å; β = 124·54±0·05°) was determined by 3-D least-squares methods. The alumino-silicate framework is composed of 4-, 5-, and 8-membered rings of tetrahedra. There are two sets of intersecting channels each defined by 8-membered rings. The (Ca, Na) atoms in the channels are in contact with seven water molecules and two oxygen atoms giving a coordination of nine at a cut-off distance of 2·77 Å. The average tetrahedral distance is lower than for anhydrous framework alumino-silicates but consistent with some other zeolite structures. Partial Al-Si ordering exists with one tetrahedron occupied preferentially by aluminum. This tetrahedron contains the two oxygen atoms that are coordinated with the (Ca, Na) atom.

scholarly journals Crystal structure of Tetraaqua(ethylenediamine)nickel(II) sulfate dihydrate and of Tetraaqua(2,2'-bipyridyl)nickel(II) sulfate dihydrate

1984 ◽  
Vol 37 (5) ◽  
pp. 921 ◽  
Author(s):  
PC Healy ◽  
JM Patrick ◽  
AH White
Keyword(s):  
Crystal Structure ◽  
Water Molecule ◽  
Single Crystal ◽  
Least Squares ◽  
Crystal Structures ◽  
X Ray Diffraction ◽  
Full Matrix ◽  
X Ray ◽  
Oxygen Atoms

The crystal structures of the title compounds, [Ni(OH2)4(en)] [SO4].2H2O, (1), and [Ni(OH2)4(bpy)]- [SO4].2H2O, (2), have been determined by single-crystal X-ray diffraction methods at 295 K, being refined by full matrix least-squares methods to residuals of 0.028,0.031 for 1852, 4323 independent 'observed' reflections respectively. Crystals of (1) are monoclinic, C2/c, a 9.459(4), b 12.192(7), c 12.294(3) �, β 119.84(4)�, Z 4. In the cation, Ni-N is 2.061(2) �; Ni-O (trans to O, N respectively) are 2.106(2), 2.063(2) �. Instead of being enlarged above 90� as predicted from repulsion theory, the angle between the pair of oxygen atoms trans to nitrogen is diminished, being 87 14(7)�. Crystals of (2) are triclinic, P1, a 11.476(5), b 9.351(5), c 7.793(4) �, α 77.63(4), β 83.52(3), γ87.40(4)�, Z 2. In the cation, Ni-N are both 2.063(2) �. Ni-O (trans to N, O respectively) are 2.060(2), 2.O42(2); 2.O80(2), 2�. The short Ni-O distance [2.042(2)�] is associated with the coordination of a trigonal water molecule.

scholarly journals The Crystal Structure of the [Pt(diethylenetriamine)Br]Br Complex

1975 ◽  
Vol 53 (8) ◽  
pp. 1139-1143 ◽  
Author(s):  
Robert Melanson ◽  
Joseph Hubert ◽  
F. D. Rochon
Keyword(s):  
Crystal Structure ◽  
Least Squares ◽  
Thermal Parameters ◽  
Platinum Atom ◽  
Molecular And Crystal Structure ◽  
X Ray Diffraction ◽  
Full Matrix ◽  
Space Group ◽  
X Ray ◽  
Cell Parameters

The molecular and crystal structure of the [Pt(dien)Br]Br complex (dien = diethylenetriamine) has been studied by X-ray diffraction. The compound belongs to the orthorhombic Pca21 space group and the cell parameters are: a = 14.211, b = 4.940, c = 13.450 Å, and Z = 4. The refinement of the positional and anisotropic thermal parameters, carried out by full matrix least squares calculations, converged to R = 0.039 and Rw = 0.036.The coordination around the platinum atom is planar. The crystal consists of alternate layers of [Pt(dien)Br]+ cations and Br− ions parallel to the ac plane.

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.

scholarly journals Crystal structure of CaK2As2O7 and CdK2P2O7

1976 ◽  
Vol 54 (21) ◽  
pp. 3319-3324 ◽  
Author(s):  
Romolo Faggiani ◽  
Crispin Calvo
Keyword(s):  
Crystal Structure ◽  
Least Squares ◽  
Coordination Sphere ◽  
Divalent Cations ◽  
Lattice Parameters ◽  
Full Matrix ◽  
Space Group ◽  
Bond Lengths ◽  
The Mean ◽  
Oxygen Atoms

Crystals of CaK2As2O7 and CdK2P2O7, both grown from the melt, are monoclinic with Z = 4. The lattice parameters are a = 9.222(6), b = 5.835(3), c = 14.698(10) Å, β = 105.84(5)° with space group P21/c for the diarsenate and a = 9.737(2), b = 5.548(1), c = 12.766(2) Å, β = 106.50(2)° with space group C2/c for the diphosphate. The structures were refined by full-matrix least-squares methods utilizing 2070 reflections (R = 0.056) for the diarsenate and 1145 reflections (R = 0.067) for the diphosphate. Both structures contain pseudo-hexagonally packed anions, in staggered configurations, forming layers with the divalent cations in six coordinate sites between the layers. The average M—O bond lengths are 2.342 and 2.290 Å for M = Ca and Cd respectively. The K ion has nine oxygen atoms with mean K—O bond lengths of 2.943 and 3.020 Å in the diarsenate in the coordination sphere. The mean of the ten shortest K—O is 2.939 Å in the diphosphate.

Crystal growth and crystal structure of arsenicv ditelluroidide semihydrate, AsTe2I · 0.5 H2O

1994 ◽  
Vol 209 (11) ◽  
Author(s):  
A. C. Stergiou
Keyword(s):  
Crystal Structure ◽  
Crystal Growth ◽  
Least Squares ◽  
Single Crystals ◽  
Thermal Parameters ◽  
Full Matrix ◽  
Distorted Octahedra

AbstractSingle crystals of arsenicSolution of the structure was performed by Patterson methods combined with successive Fourier syntheses. The positional and anisotropic thermal parameters were refined by full-matrix least-squares calculations. All reflections were corrected for absorption (The As atoms are surrounded by six [Te, I] atoms, three with shorter and three with longer distances, forming strongly distorted octahedra. Each of the As(1) octahedra is linked with three As(2) octahedra by common edges [Te, I](1)–[Te, I](2), and vice versa, forming an infinite band perpendicular to the

The crystal structure of BiOCl

1993 ◽  
Vol 205 (1) ◽  
Author(s):  
K. G. Keramidas ◽  
G. P. Voutsas ◽  
P. I. Rentzeperis
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Least Squares ◽  
Thermal Parameters ◽  
Full Matrix ◽  
Anisotropic Temperature ◽  
Computer Controlled ◽  
Cl Atoms ◽  
Temperature Factors ◽  
Isosceles Triangles

AbstractThe crystal structure of BiOCl has been redetermined with 3570 observed reflections of which 174 were unique measured on a computer controlled Philips PW 1100 single crystal diffractometer. The structure belongs to the tetragonal space groupThe positional and thermal parameters, with anisotropic temperature factors, were refined by full-matrix least-squares calculations to a finalEach Bi atom is eight-coordinated by 4 O and 4 Cl atoms at distances of 2.316 Å and 3.059 Å respectively thus forming a decahedron. The faces of the decahedron are 2 rectangles (O–O–O–O and Cl–Cl–Cl–Cl) with sides 3.487 Å and 8 isosceles triangles (four O–Cl–O and four Cl–O–Cl) with sides O–Cl 3.249 Å and O–O or Cl–Cl 3.487 Å.The decahedra are linked to each other by a common O–Cl edge along the

Crystal structure of ammonium cis-Tetraamminedisulfitocobaltate(III) trihydrate (a redetermination)

1978 ◽  
Vol 31 (5) ◽  
pp. 999 ◽  
Author(s):  
CL Raston ◽  
AH White ◽  
JK Yandell
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonding ◽  
Least Squares ◽  
Title Compound ◽  
Structural Data ◽  
Water Molecules ◽  
Hydrogen Atoms ◽  
Full Matrix ◽  
The Difference

The crystal structure of the title compound, NH4 [Co(NH3)4(SO3)2],3H2O, has been redetermined using diffractometer data at 295 K and refined by full-matrix least squares to a residual of 0.056 for 2068 'observed' reflections. Crystals are orthorhombic, P212121, a 10.978(4), b 17.552(7), c 6.828(3)Ǻ, Z 4. The redetermined structure provides accurate structural data for the cobalt environment; as well, it locates all hydrogen atoms and defines cations and water molecules un- ambiguously. Co-S are 2.224(2), 2.221(2) Ǻ. Co-N (trans to S) (1.993(6), 2.023(6) Ǻ) are longer than the mutually trans Co-N (1.970(7), 1.977(6) Ǻ); the difference in the former is a consequence of lattice hydrogen bonding.

The molecular and crystal structure of tetrakis(4-methylpyridine)cobalt(II) hexafluorophosphate

1979 ◽  
Vol 57 (2) ◽  
pp. 135-138 ◽  
Author(s):  
Raymond M. Morrison ◽  
Robert C. Thompson ◽  
James Trotter
Keyword(s):  
Crystal Structure ◽  
Least Squares ◽  
Thermal Parameters ◽  
Crystal Symmetry ◽  
Molecular And Crystal Structure ◽  
Distorted Octahedron ◽  
Distorted Tetrahedron ◽  
Fourier Methods ◽  
Full Matrix ◽  
Space Group

Crystals of tetrakis(4-methylpyridine)cobalt(II) hexafluorophosphate, C24H28CoF12N4P2, are tetragonal, space group I41/acd, a = 18.434(7), c = 18.818(6) Å, Z = 8. The structure was solved by direct and Fourier methods. The positional and anisotropic thermal parameters were refined by full-matrix least-squares methods to R = 0.072 for 346 observed reflexions. The structure consists of discrete [Co(4-mepy)4]2+ and PF6− ions. The structure of the cation is a distorted tetrahedron of 4-methylpyridine ligands around cobalt (crystal symmetry S4) and that of the anion is a distorted octahedron of fluorines around phosphorus (crystal symmetry C2).

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