Crystal Structure of LiVO3

1973 ◽  
Vol 51 (2) ◽  
pp. 265-273 ◽  
Author(s):  
Robert D. Shannon ◽  
Crispin Calvo
Keyword(s):  
Crystal Structure ◽  
Bond Strength ◽  
Bond Length ◽  
Least Squares ◽  
Mean Value ◽  
Space Group ◽  
The Mean ◽  
Probable Space ◽  
Lithium Metavanadate ◽  
Edge Shared Octahedra

Lithium metavanadate is monoclinic with a = 10.158(2), b = 8.4175(9), c = 5.8853(9) Å, β = 110.48(2)° and probable space group C2/c. The structure, refined by least-squares to a ωR = 0.033 using 851 reflections, is isotypic with LiAlSi2O6 (spodumene) and LiFeSi2O6. Bands of Li—O edge-shared octahedra run parallel to c and are linked by chains of VO4 tetrahedra which also run parallel to c. The mean Li(1)—O and Li(2)—O distances are significantly different, 2.153(3) and 2.284(3) Å, and are related to the degree of distortion of individual distances from the mean. The V—O distances of 1.821, 1.795, 1.662, and 1.628 Å with a mean value of 1.725 Å are consistent with bond strength sums around the oxygen atoms and empirical bond length – bond strength curves.

Kristallstruktur von Pyrrolidinium-bis(diisopropylphosphinoyl)phosphid, einem System mit zweifach koordiniertem Phosphor /Crystal Structure of Pyrrolidinium-bis(diisopropylphosphinoyl)phosphide, a System with Bicoordinated Phosphorus

1983 ◽  
Vol 38 (2) ◽  
pp. 208-211 ◽  
Author(s):  
Dieter Weber ◽  
Karl Peters ◽  
Hans Georg von Schnering ◽  
Ekkehard Fluck
Keyword(s):  
Crystal Structure ◽  
Bond Length ◽  
Phosphorus Atom ◽  
Electron Pairs ◽  
Space Group ◽  
The Mean ◽  
Phosphor Crystal

Abstract Pyrrolidinium-bis(diisopropylphosphinoyl)phosphide crystallizes triclinically in the space group P1̄ with a = 1019.6(8), b = 1271.5(4), c = 999.5(7) pm, a = 100.90(5)°, β = 91.24(5)°, γ = 99.10(5)° and Z = 2 formula units. The mean P-P bond length is 212.2 pm and hence shorter than in derivates in which the electron pairs of the bicoordinated phosphorus atom are bonded to one or two M(CO)5-groups. Additional pπ-dπ bonding explains the shortening of the P-P bond.

The crystal structure of p-diethylaminobenzenediazonium hexafluorophosphate

1985 ◽  
Vol 63 (2) ◽  
pp. 332-335 ◽  
Author(s):  
Richard G. Ball ◽  
Richard MacLeod Elofson
Keyword(s):  
Crystal Structure ◽  
Least Squares ◽  
Triple Bond ◽  
Direct Methods ◽  
Full Matrix ◽  
Space Group ◽  
Bond Lengths ◽  
The Mean ◽  
Least Squares Techniques ◽  
Diazo Group

p-Diethylaminobenzenediazonium hexafluorophosphate, C10H14N3+•PF6−, crystallized in space group [Formula: see text] with a = 12.105(4), b = 12.340(5), c = 10.439(4) Å, α = 96.53(3), β = 104.11(3), γ = 64.44(3)°, and Z = 4. The structure was solved using direct methods and refined with full-matrix least-squares techniques on F, to a final R of 0.054 for 1917 reflections with F2 > 3σ(F2). The mean bond lengths for the diazo group are: N—N 1.096(6); C—N 1.357(7) Å. The geometry of the molecule is discussed in terms of the possible resonance forms and it is shown to be consistent with a form in which the N—N triple bond is essentially intact and the aminobenzene moiety has "quinoidal" character.

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.

Die Kristallstruktur des dimeren Dimethylantimontrichlorids und des Tetramethylantimon-hexachloroantimonats [(CH3)2SbCl3]2 und [(CH3)4Sb] + [SbCl6]- / Crystal Structure of the Dimeric Dimethylantimony Trichloride and Tetramethylantimony Hexachloroantimonate [(CH3)2SbCl3]2 and [(CH3)4Sb]+[SbCl6]-

1978 ◽  
Vol 33 (5) ◽  
pp. 485-488 ◽  
Author(s):  
Wolfgang Schwarz ◽  
Hans-Jürgen Guder
Keyword(s):  
Crystal Structure ◽  
Mean Value ◽  
Orthorhombic Space Group ◽  
Chlorine Atoms ◽  
Coordination Polyhedra ◽  
Triclinic Space Group ◽  
Mean Values ◽  
Space Group ◽  
Lattice Constants ◽  
The Mean

Dimethylstibonium trichloride (CH3)2SbCl3 exists in two isomeric forms. In the dimeric "covalent" one, [(CH3)2SbCl3]2, two formula units are bridged by chlorine, building a fourmembered ring. It crystallizes in the orthorhombic space group Pnma with lattice constants a = 1212.9, b = 1910 and c = 610.2 pm. The mean value of bond length from antimony to the terminal chlorine atoms is 235.5 pm, to the bridging chlorine atoms 280.0 pm and the averaged Sb-C distance is 213.3 pm. The second form [(CH3)4Sb]+[SbCl6]- is an ionic one and crystallizes in the triclinic space group P1̅ with lattice constants a = 715.6, b = 744.2, c = 1415.2 pm, a = 90.01, β = 93.39 and γ = 106.4°. The mean values of bond lengths are Sb-C 211.5 pm and Sb-Cl 238.2 pm. The tetrahedrical as well as the octahedrical coordination polyhedra are only slightly distorted.

The crystal and molecular structure of quaterrylene

1960 ◽  
Vol 257 (1291) ◽  
pp. 477-490 ◽  
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Crystal And Molecular Structure ◽  
Current Theory ◽  
Mean Value ◽  
Unit Cell ◽  
Two Dimensional ◽  
Monoclinic System ◽  
Space Group ◽  
The Mean

Quaterrylene (III) is isotypic with perylene (I); it crystallizes in the monoclinic system with a = 11·25, b = 10·66, c = 19·31 Å, β = 100·6°, and with four molecules per unit cell and the space group P 2 1 / a . The crystal structure has been determined by two-dimensional methods. In the b -axial projection a majority of the carbon atoms are resolved, and, since the molecule lies with its greatest length almost exactly perpendicular to this axis, the lengths of the peri -bonds connecting the naphthalenic residues have been determined with moderate accuracy. The mean value is assessed at 1·53 ± 0·01 Å, which is significantly larger than current theory predicts. Possible reasons for this difference are discussed.

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 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.

Structure of Nickel Orthophosphate

1975 ◽  
Vol 53 (10) ◽  
pp. 1516-1520 ◽  
Author(s):  
Crispin Calvo ◽  
Romolo Faggiani
Keyword(s):  
Bond Length ◽  
Least Squares ◽  
Monoclinic System ◽  
Full Matrix ◽  
Space Group ◽  
Bond Lengths ◽  
The Mean ◽  
R Value ◽  
Cation Sites

Ni3P2O8 crystallizes in the monoclinic system with space group P21/c with a = 5.830(2), b = 4.700(2), c = 10.107(4) Å, β = 91.22(2)°, and Z = 2. The structure was refined by full-matrix least squares methods to a final R value of 0.035 using 986 symmetry independent reflections. The structure is isotypic with that of sarcopside, which in turn is related to that of olivine with vacant cation sites ordered. The Ni ions are octahedrally coordinated in two types of sites with average Ni—O bond lengths of 2.081 and 2.067 Å. The mean P—O bond length is 1.547 Å although the tetrahedron shows some unusually large distortions with bond lengths ranging from 1.521 to 1.595 Å.

Crystal Structure of the Glaserite Form of BaNaPO4

1975 ◽  
Vol 53 (12) ◽  
pp. 1849-1853 ◽  
Author(s):  
Crispin Calvo ◽  
Romolo Faggiani
Keyword(s):  
Crystal Structure ◽  
Bond Length ◽  
Least Squares ◽  
Coordination Number ◽  
Cation Site ◽  
Full Matrix ◽  
Space Group ◽  
Bond Lengths ◽  
R Value ◽  
Cation Sites

Crystals of BaNaPO4 were grown from a Ba3P2O8–Na2B4O7 melt. The crystals are trigonal, space group [Formula: see text]with a = 5.622(4) and c = 7.259(5) Å. The structure, isotypic with that of glaserite, was refined by full-matrix least-squares methods to a final R value of 0.042 using 218 unique reflections. There are three different cation sites. Na and Ba lie at sites of [Formula: see text] symmetry and are coordinated to 6 and 12 oxygen atoms respectively. The Na—O bond lengths are 2.344(7) Å and the two unique Ba—O bond lengths are 2.788(7) and 3.247(9) Å. The remaining cation site has 3m symmetry, a coordination number of 10, and contains equal amounts of Na+ and Ba2+. The bond lengths range from 2.548(12) to 3.017(7) Å. The phosphate group also has 3m symmetry with mean P—O bond lengths of 1.538 Å. The underbonded apical P—O bond length is 1.520 Å.

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