Crystal Structure of Zn3V0.5P1.5O8

1975 ◽  
Vol 53 (23) ◽  
pp. 3665-3668 ◽  
Author(s):  
K. Loralee Idler ◽  
Crispin Calvo
Keyword(s):  
Crystal Structure ◽  
Bond Length ◽  
Least Squares ◽  
Population Analysis ◽  
Stable Phase ◽  
Zinc Ions ◽  
Unit Cell Parameters ◽  
Full Matrix ◽  
Cell Parameters ◽  
Site Population

The stable phase in the Zn3(PO4)2–Zn3(VO4)2 system near 25 mol% Zn3(VO4)2 is monoclinic with space group C2/c and unit cell parameters a = 15.941(6), b = 5.314(2), c = 8.265(2) Å, β = 106.96(3)° and Z = 4. The structure was refined by full-matrix least-squares methods using 910 reflections, R = 0.073. The composition, Zn3P1.50V0.50(4)O8, was determined by site population analysis with the V and P randomly distributed. One-third of the zinc ions lie on twofold axes and these show an average Zn—O bond length of 1.955 Å while the remaining ZnO4 group has a mean Zn—O bond length of 1.948 Å. The structure consists of sheets parallel to (100) formed of chains containing rings of corner shared Zn(1)O4 and (V,P)O4 tetrahedra. The Zn(2)O4 groups, in turn, form chains parallel to the b axis through corner sharing.

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.

The preparation and crystal structure of η2-nitrato(η4-hexadecamethylcyclooctaphosphazene (N1,N2,N4,N5))cobalt(II) nitrate

1981 ◽  
Vol 59 (16) ◽  
pp. 2435-2440 ◽  
Author(s):  
Keith D. Gallicano ◽  
Norman L. Paddock ◽  
Steven J. Rettig ◽  
James Trotter
Keyword(s):  
Crystal Structure ◽  
Bond Length ◽  
Least Squares ◽  
Cobalt Atom ◽  
Direct Methods ◽  
Nitrate Anion ◽  
Hydrogen Atoms ◽  
Nitrate Ion ◽  
Full Matrix ◽  
Local Conformation

Hexadecamethylcyclooctaphosphazene N8P8Me16, 1, forms a 1:1 complex, 2, with cobalt(II) nitrate. Crystals of 2 are triclinic, a = 10.891(2), b = 11.201(2), c = 14.944(2) Å, α = 93.21(1), β = 95.66(1), γ = 104.69(1)°, Z = 2, space group [Formula: see text]. The crystal structure was solved by direct methods and was refined by full-matrix least-squares procedures to R = 0.037 and Rw = 0.047 for 5165 reflections with I ≥ 3σ(I). All the hydrogen atoms were found. The structure consists of a cation [N8P8Me16CoNO3]+ and a free nitrate anion. The cobalt atom is coordinated by an unsymmetrical bidentate nitrate ion and by four nitrogen atoms of the phosphazene ring. The metal is attached near one end of the ring, forming six-, ten-, and two four-membered chelate rings, and induces bond length variations which are independent of local conformation and which arise from the localization of bonding electrons.

scholarly journals Synthesis, Characterization, and Crystal Structure of Negundoside (2′-p-Hydroxybenzoyl Mussaenosidic Acid)

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Suresh Sharma ◽  
B. D. Gupta ◽  
Rajni Kant ◽  
Vivek K. Gupta
Keyword(s):  
Crystal Structure ◽  
Room Temperature ◽  
Direct Method ◽  
Monoclinic Crystal System ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
Monoclinic Crystal ◽  
Full Matrix ◽  
X Ray ◽  
Cell Parameters

The structure of title compound Negundoside (2′-p-hydroxybenzoyl mussaenosidic acid) was established by spectral and X-ray diffraction studies. The compound crystallizes in the monoclinic crystal system with space group P21 having unit cell parameters: a=11.6201 (5) Å, b=9.2500 (4) Å, c=12.2516 (5) Å, β=97.793 (4)°, and Z=2. The crystal structure was solved by direct method using single crystal X-ray diffraction data collected at room temperature and refined by full-matrix least-squares procedures to a final R value of 0.0520 for 3389 observed reflections.

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.

RICICLE: A FORTRAN program to refine unit cell parameters of incommensurate structures

1993 ◽  
Vol 8 (3) ◽  
pp. 168-172 ◽  
Author(s):  
R. I. Smith
Keyword(s):  
Least Squares ◽  
Powder Diffraction ◽  
Fortran Program ◽  
Unit Cell ◽  
Unit Cell Parameters ◽  
Full Matrix ◽  
Cell Parameters ◽  
Incommensurate Structures ◽  
Diffraction Patterns ◽  
Modulation Vector

A FORTRAN 77 program to perform full matrix least-squares refinement of unit cell parameters from powder diffraction patterns showing incommensurate supercell reflections is described. The code is completely general, being applicable to any crystal system, and can refine all three unit cell edges and angles and, in the presence of an incommensurate supercell, can refine the components of the modulation vector along all three reciprocal axes. Estimated standard deviations on all the refined parameters are calculated analytically.

The Crystal Structure of S-Methyl 1-[Dicyclohexyl(thiophosphoryl)]-dithioformate: (c-C6H11)2P(S)C(S)Sme

1988 ◽  
Vol 41 (3) ◽  
pp. 405 ◽  
Author(s):  
BF Hoskins ◽  
ERT Tiekink
Keyword(s):  
Crystal Structure ◽  
Title Compound ◽  
Direct Methods ◽  
Mirror Plane ◽  
Unit Cell Parameters ◽  
Orthorhombic Space Group ◽  
Interatomic Distances ◽  
Full Matrix ◽  
Cell Parameters ◽  
Compound C

The crystal structure of the title compound, (c-C6H11)2P(S)C(S)SMe , has been determined and shows that the P(S)C(S)SC chromophore is situated on a crystallographic mirror plane with the cyclohexyl groups related to each other across this plane. Significant interatomic distances are: P=S 1.951(1), P-C 1.860(4), C=S 1.632(4) and C-S 1.700(4)Ǻ. A resonance scheme involving the delocalization of π-electrons over the CS2 moiety has been invoked to account for the observed C-S bond distances in the molecule. Crystals are orthorhombic, space group Pnma with unit cell parameters a 10.196(2), b 10.612(1) and c 15.370(3)Ǻ, and Z 4. The structure was solved by direct methods and refined by a full-matrix least-squares procedure to final R 0.045, Rw 0.047 for 1191 reflections with I ≥ 3.0σ(I).

Crystal structure of N,N′-dimethyl-2-imidazolidinethione, a by-product from the reaction of Na2(CH2N(CH3)CS2)2 and HgCl2

1983 ◽  
Vol 61 (1) ◽  
pp. 211-213 ◽  
Author(s):  
Chung Chieh ◽  
Sing Kwen Cheung
Keyword(s):  
Crystal Structure ◽  
Bond Length ◽  
Least Squares ◽  
Aqueous Ethanol ◽  
Ethanol Solution ◽  
Aqueous Ethanol Solution ◽  
Hydrogen Atoms ◽  
Full Matrix ◽  
Space Group ◽  
Automatic Diffractometer

The reaction between mercury (II) chloride and N,N′-dimethylethylenebisdithiocarbamate gave a white precipitate. In an attempted recrystallization from an aqueous–ethanol solution, a cyclic thiourea-type compound, N,N′-dimethyl-2-imidazolidinethione, was obtained. The crystals of this compound are monoclinic, a = 10.388(2), b = 6.139(1), c = 12.291(4) Å, β = 118.64(2), and space group P21/c. The non-hydrogen atoms of the molecule are planar and the C=S bond length is 1.673(4) Å. The structure was refined by full-matrix least-squares from 642 independent reflections measured on an automatic diffractometer to R and Rw of 0.053 and 0.068, respectively.

The crystal chemistry of the amphiboles. III: Refinement of the crystal structure of a sub-silicic hastingsite

1977 ◽  
Vol 41 (317) ◽  
pp. 43-50 ◽  
Author(s):  
F. C. Hawthorne ◽  
H. D. Grundy
Keyword(s):  
Crystal Structure ◽  
Chemical Composition ◽  
Bond Length ◽  
Least Squares ◽  
Crystal Chemistry ◽  
Least Squares Method ◽  
Three Dimensional ◽  
Full Matrix ◽  
Positional Disorder ◽  
The Mean

SummaryThree-dimensional counter-diffractometer data and a full-matrix least-squares method have been used to refine the crystal structure of a sub-silicic hastingsite in the space group C2/m. The chemical composition of the amphibole is with ceil parameters a = 9·8659(4), b = 18·0139(8), c = 5·3545(2)Å, and β = 105·082(1)°. Unit weights were used throughout the refinement and the final R-factor for 1263 observed non-equivalent reflections was 4.1%. The mean tetrahcdral bond length for aluminous amphiboles varies linearly with the total amount of tetrahedral A1. Curves are derived relating individual mean bond lengths with A1 occupancy. The positional disorder on the A-site of the aluminous amphiboles appears to be partly related to the amount of substitution of A1 into the T(2) tetrahedron.

scholarly journals Synthesis, Characterization, and X-Ray Crystal Structure of Bis(O-amyl dithiocarbonato-κ2S,S′)bis(4-cyanopyridine-κN)nickel(II)

2014 ◽  
Vol 2014 ◽  
pp. 1-5
Author(s):  
Kuldeep Singh ◽  
Sanjay Kapoor ◽  
Renu Sachar ◽  
Vivek K. Gupta ◽  
Rajni Kant
Keyword(s):  
Crystal Structure ◽  
Magnetic Moment ◽  
Direct Methods ◽  
Title Complex ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
Orthorhombic Space Group ◽  
Full Matrix ◽  
X Ray ◽  
Cell Parameters

The [Ni(S2CO-n-C5H11)2(C6H4N2)2] adduct of 4-cyanopyridine with [Ni(S2CO-n-C5H11)2] was synthesized and characterized by elemental analysis, magnetic susceptibility measurement, IR, electronic spectral data, and X-ray diffraction analysis. The Ni atom in the title complex is octahedrally coordinated within a trans-N2S4 donor set, with the Ni atom located on a centre of inversion. The title compound exhibits magnetic moment value (3.20 B.M) which is in agreement with magnetic moment values observed for paramagnetic octahedral complexes of nickel(II). The title complex crystallizes in the orthorhombic space group Pbca with unit cell parameters a = 11.455(5), b = 9.602(4), and c = 26.374(1) Å. Crystal structure was solved by direct methods and refined by full matrix least-squares procedures to a final R value of 0.0499 for 2004 observed reflections. The amyl chain is disordered over two sets of sites, with occupancy ratios of 0.595 : 0.405. Infinite long chains of molecules are formed with the help of C–H⋯N hydrogen bond.

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