Crystal Structure of α-Zn2V2O7

1973 ◽  
Vol 51 (7) ◽  
pp. 1004-1009 ◽  
Author(s):  
Ramanathan Gopal ◽  
Crispin Calvo
Keyword(s):  
Crystal Structure ◽  
Oxygen Atom ◽  
Bond Length ◽  
Fold Axis ◽  
Full Matrix ◽  
X Ray ◽  
R Value ◽  
The Individual ◽  
Zn Ions ◽  
Oxygen Atoms

α-Zn2V2O7 is monoclinic with lattice parameters a = 7.429(5), b = 8.340(3), c = 10.098(3) Å, β = 111.37(5)°, Z = 4 and space group C2/c. The structure was refined using a full matrix least-squares with 1034 reflections measured with a quarter-circle General Electric automatic X-ray diffractometer to a final R value of 0.066. The anion consists of a pair of VO4 tetrahedra sharing an oxygen atom which lies on a two-fold axis. The bridging V—O bond length is 1.775(4) Å while the three independent terminal ones are 1.728(4), 1.704(7), and 1.658(8) Å long. These bond lengths are consistent with the charge character around the individual oxygen atoms. The Zn ions are coordinated to five oxygen atoms with Zn—O bonds ranging from 1.973 to 2.088°Å. The structure is similar to that of α-CU2P2O7 and transforms to the thortvietite structure at about 615 °C.

Crystal structure of tetraammonium diphosphate, (NH4)4P2O7 at 22 °C

1976 ◽  
Vol 54 (13) ◽  
pp. 2025-2028 ◽  
Author(s):  
Nora Middlemiss ◽  
Crispin Calvo
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bond ◽  
Oxygen Atom ◽  
Bond Length ◽  
Fold Axis ◽  
Hydrogen Atoms ◽  
Monoclinic System ◽  
Full Matrix ◽  
R Value ◽  
Oxygen Atoms

Crystals of tetraammonium diphosphate, (NH4)4P2O7, crystallize in the monoclinic system with space group C2/c, Z = 4 and lattice parameters a = 11.758(3), b = 6.486(2), c = 13.659(2) Å and β = 104.81(1)°. The structure was refined using full-matrix least-squares methods with 810 reflections to an R value of 0.092. The diphosphate anion contains a crystallographic two-fold axis, and has a configuration intermediate between staggered and eclipsed. The bridging P—O bond length is 1.624(2) Å and the terminal P—O bonds average 1.507 Å. The diphosphate groups lie in sheets defined by [Formula: see text] and are bridged by NH4+ groups which hydrogen bond to only the terminal oxygen atoms. Each hydrogen is bonded to one oxygen atom but each of the terminal oxygen atoms interacts with either two or three hydrogen atoms.

Crystal Structure of α-VPO5

1973 ◽  
Vol 51 (16) ◽  
pp. 2621-2625 ◽  
Author(s):  
Byron Jordan ◽  
Crispin Calvo
Keyword(s):  
Crystal Structure ◽  
Oxygen Atom ◽  
Least Squares ◽  
Least Squares Method ◽  
Fold Axis ◽  
Full Matrix ◽  
Bond Lengths ◽  
R Value ◽  
A Site ◽  
Vanadium Ion

α-VPO5 crystallizes in the tetragonal space group P4/n with a = 6.014(7) and c = 4.434(2) Å. The structure, isotypic with that of α-VSO5, was refined by full-matrix least-squares method to an R value of 0.089 using 239 independent reflections. The vanadium ion lies on a crystallographic four-fold axis, as does one of the oxygen atoms, and the P on a site of [Formula: see text] symmetry. A second oxygen atom, as a result of disorder, occurs in two positions which are mirror reflected with respect to the ac plane. The structure consists of highly distorted VO6 groups with bond lengths along the c axis of 1.580(11) and 2.853(11) Å while the remaining four V—O bond lengths are all 1.858(8) Å. The P—O bond lengths in the PO4. tetrahedron are 1.541(8) Å with the PO4 groups bridging across four chains of VO6 groups.

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.

Synthese und Kristallstruktur von l,13-Bis(8-chinolyl)- 1,4,7,10,13-pentaoxatridecan-diquecksilber(I)-diperchlorat

1991 ◽  
Vol 46 (1) ◽  
pp. 1-4 ◽  
Author(s):  
Klaus Brodersen ◽  
Jörg Zimmerhackl
Keyword(s):  
Crystal Structure ◽  
Aqueous Solution ◽  
X Ray Diffraction ◽  
Triclinic Space Group ◽  
Space Group ◽  
X Ray ◽  
R Value ◽  
Torsional Angles ◽  
L 13 ◽  
Oxygen Atoms

1,13-Bis(8-quinolyl)-1,4,7,10,13-pentaoxatridecane-dimercury(I)-diperchlorate is formed by the reaction of 1,13-bis(8-quinolyl)-1,4,7,10,13-pentaoxatridecane in ethanol with an aqueous solution of dimercury(I)-diperchlorate.It crystallizes in the triclinic space group P Ī with a = 1020.6(2), b = 1200.6(8), c = 1441.1(6) pm , α = 69.60(5)°, β = 83.04(13)°, y = 66.53(4)° and Z = 2. The crystal structure was determined by X -ray diffraction and refined to an R-value o f 0.079. The Hg22+ -ion is coordinated to both nitrogen atoms and four oxygen atoms of one molecule of the ligand. By changing four C - O torsional angles from trans to gauche, the ligand adopts a helical, chiral configuration around the Hg22+-ion. The CIO4--ions are not coordinated to the Hg22+-ion.

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.

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.

Crystal Structure of Lead meta Vanadate, PbV2O6

1974 ◽  
Vol 52 (15) ◽  
pp. 2701-2704 ◽  
Author(s):  
Byron D. Jordan ◽  
Crispin Calvo
Keyword(s):  
Crystal Structure ◽  
Spherical Shell ◽  
Lead Ion ◽  
Orthorhombic Space Group ◽  
Full Matrix ◽  
Distorted Octahedra ◽  
R Value ◽  
Vanadium Ions ◽  
Automatic Diffractometer ◽  
Oxygen Atoms

PbV2O6 crystallizes in the orthorhombic space group Pnma with a = 9.771(10), b = 3.684(4), c = 12.713(13) Å, and Z = 4. The structure was determined using 816 reflections measured with an automatic diffractometer and refined by full-matrix least squares to an R value of 0.052. The two unique vanadium ions lie on mirror planes and are each coordinated to five oxygen atoms lying between 1.61 and 2.06 Å. The distorted octahedra are completed by a sixth V–O interaction which is 2.73 Å for V(1) and is 2.57 Å for V(2). The lead ion is coordinated to nine oxygen atoms lying in a spherical shell with inner and outer radii of 2.56 and 2.90 Å. The structure consists of chains of VO6 octahedra paralleling the b axis.

Crystal Structure of Synthetic Mg-Whitlockite, Ca18Mg2H2(PO4)14

1974 ◽  
Vol 52 (7) ◽  
pp. 1155-1164 ◽  
Author(s):  
Ramanathan Gopal ◽  
Crispin Calvo ◽  
Jun Ito ◽  
W. K. Sabine
Keyword(s):  
Crystal Structure ◽  
Oxygen Atom ◽  
Least Squares ◽  
Formula Unit ◽  
Full Matrix ◽  
Space Group ◽  
R Value ◽  
Unit Density ◽  
A Chain ◽  
Automatic Diffractometer

Crystals of synthetic Mg-whitlockite, Ca18Mg2H2(PO4)14, have been grown by hydrothermal techniques and their structure refined by full-matrix least-squares methods, using 1626 unique reflections measured with a Syntex [Formula: see text] automatic diffractometer, to a final R value of 0.046. The crystals have space group R3c with ZR = 1, a = 13.765(8) Å and α = 44.25(5)° with the equivalent hexagonal parameters a = 10.350(5), c = 37.085(12) Å and ZH = 3. The structure, although similar to that of βCa3(PO4)2, differs significantly. The structure contains interconnected infinite chains of polyhedra paralleling the hexagonal c axis with links in the chains consisting of three CaO8 polyhedra separated by two PO4 tetrahedra. Six of these chains surround a chain of MgO6 octahedra and PO4H groups which lie on the three-fold axes. These chains however contain only half the formula unit density of the calcium containing ones and a proton, presumably disordered, is attached to the oxygen atom on the triad axes.

Crystal Structure of Tetraethylammonium Bromopentacarbonyltungstate(0)

1995 ◽  
Vol 48 (5) ◽  
pp. 1045 ◽  
Author(s):  
T Whyte ◽  
GA Williams
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Least Squares ◽  
X Ray Diffraction ◽  
Full Matrix ◽  
Space Group ◽  
X Ray ◽  
Bond Lengths ◽  
R Value

The crystal structure of tetraethylammonium bromopentacarbonyltungstate (0), [NEt4] [W(CO)5Br], has been determined by single-crystal X-ray diffraction methods at 22�1°C. Crystals are tetragonal, space group P4/n, with a 9.206(2), c 10.484(2) Ǻ, and Z 2. Full-matrix least-squares refinement gave a final R value of 0.034 for 820 independent reflections. The [W(CO)5Br]- anion possesses exact C4v symmetry, with bond lengths W-Br 2.736(1), W-COtrans 1.93(1) and W-COcis 2.034(6) Ǻ.

An X-Ray Study of the Synthetic Intermediate 9-Cyano-1,10-Dimethyl-6-Ethylenedioxy-1-Octalin

1975 ◽  
Vol 53 (2) ◽  
pp. 192-194 ◽  
Author(s):  
Harry Lynton ◽  
Pik-Yuen Siew
Keyword(s):  
Crystal Structure ◽  
Total Synthesis ◽  
Direct Methods ◽  
Hydrogen Atoms ◽  
Full Matrix ◽  
X Ray ◽  
Ring Junction ◽  
Cell Dimensions ◽  
R Value ◽  
Synthetic Intermediate

The crystal structure of the synthetic intermediate, 9-cyano-1,10-dimethyl-6-ethy]enedioxy-1-octalin, C15H21O2N, was solved by direct methods. The compound crystallizes in the space group p21/c with cell dimensions a = 12.282(4), b = 7.144(3), c = 15.619(5) Å, β = 104.04(1)°. Refinement was carried out isotropically for hydrogen and anisotropically for non-hydrogen atoms using full matrix least squares to an R-value of 0.043 for 1669 observed reflections.This compound, which has a cis configuration at the octalin ring junction, is a precursor to a moiety of the alkaloid thelepogine. The cis conformation is essential for total synthesis of thelopogine by this route.

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