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.

The Structure of Na4P2O7 at 22 °C

1972 ◽  
Vol 50 (16) ◽  
pp. 2519-2526 ◽  
Author(s):  
K. Y. Leung ◽  
C. Calvo
Keyword(s):  
Least Squares ◽  
Room Temperature ◽  
Orthorhombic Space Group ◽  
Full Matrix ◽  
Space Group ◽  
Bond Lengths ◽  
R Value ◽  
Automatic Diffractometer ◽  
Oxygen Atoms

At room temperature Na4P2O7 crystallizes in the orthorhombic space group P212121 with a = 9.367(5), b = 5.390(2), c = 13.480(8) Å, and z = 4. The structure was refined by full-matrix least-squares using 1337 reflections measured with a Syntex Automatic diffractometer. The final R value is 0.022. The anion has nearly an eclipsed configuration with a P—O—P angle of 127.5(1)°. The two bridging P—O bond lengths are 1.631(2) and 1.642(2) Å with terminal P—O bond lengths averages of 1.512 and 1.514 Å on either side of the anion. Two of the four Na+ ions are coordinated to five oxygen atoms while the remainder are coordinated to six oxygen atoms. The structure contains chains of cations with four nearly collinear Na+ per cell paralleling the c axis. These are surrounded by six anions with the bridging oxygen atoms lying approximately at the corners of an octahedron with the P—P vector of the anion also paralleling the c axis. Adjacent anions along the c axis are separated by a pair of Na+ ions.

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.

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 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.

Preparation and Structure of Dibromobis(N,N-diethyldithiocarbamato)-thionitrosyltechnetium(III)

1991 ◽  
Vol 44 (8) ◽  
pp. 1125 ◽  
Author(s):  
J Baldas ◽  
SF Colmanet ◽  
GA Williams
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Title Compound ◽  
Coordination Geometry ◽  
X Ray Diffraction ◽  
Orthorhombic Space Group ◽  
Full Matrix ◽  
X Ray ◽  
Trans Influence ◽  
R Value

The title compound, [Tc (NS)(S2CNEt2)2Br2], has been prepared by the reaction of [ TcN (S2CNEt2)2] with SOBr2, and its crystal structure has been determined by single-crystal X-ray diffraction methods at 23�1°C. Crystals are orthorhombic, space group Pnma , with a 14.864(7), b 15.857(7), c 8.938(4)Ǻ, and Z 4. Full-matrix least-squares refinement gave a final R value of 0.047 for 1685 independent reflections. The technetium atom is seven-coordinate with a distorted pentagonal- bipyramidal coordination geometry. The thionitrosyl ligand and a bromo ligand occupy the axial positions, with the thionitrosyl group exerting a small trans influence with Tc-Brtrans 2.595(1) and Tc-Brcis 2.564(1)Ǻ. The coordination of the thionitrosyl group is essentially linear with Tc -N=S 177.2(7)°, Tc -N 1.754(9), and N=S 1.504(9)Ǻ.

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.

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

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.

Alkalimetallformiate, V Die Kristallstruktur von Natriumformiat-Dihydrat, NaHCO2·2H2O [1] Alkali Metal Formates, V The Crystal Structure of Sodium Formate Dihydrate, NaHCO2·2H2O [1]

1994 ◽  
Vol 49 (9) ◽  
pp. 1179-1182 ◽  
Author(s):  
Kerstin Müller ◽  
Klaus-Jürgen Range ◽  
Anton M. Heyns
Keyword(s):  
Crystal Structure ◽  
Alkali Metal ◽  
Sodium Formate ◽  
Sodium Ions ◽  
Hydrogen Atoms ◽  
Orthorhombic Space Group ◽  
Bonding System ◽  
Water Oxygen ◽  
Metal Formates ◽  
Oxygen Atoms

Single crystals of sodium formate dihydrate, NaHCO2·2H2O, have been prepared from aqueous solutions of sodium formate, NaHCO2, via the trihydrate, NaHCO2-3H2O. They are orthorhombic, space group Cmca, with a = 7.070(4), b = 14.534(2), c = 8.706(2) Å and Z = 8. The structure, including the hydrogen atoms, was refined to R = 0.054, Rw = 0.065 for 479 unique reflections with I > 3 σ (I). It comprises buckled layers formed by NaO6 octahedra which are edge- and corner-sharing. The octahedral coordination of the sodium ions is achieved by two oxygen atoms from two different end-on bonded formate ions and four water oxygen atoms. The O···H distances show clearly that strong hydrogen bonds are not involved in the bonding system

Synthetic plant growth regulators. V. The synthesis and crystal structure of a hybrid gibberellin-helminthosporic acid

1980 ◽  
Vol 33 (5) ◽  
pp. 1061 ◽  
Author(s):  
JV Turner ◽  
BF Anderson ◽  
LN Mander
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Carboxylic Acid ◽  
Standard Procedure ◽  
Direct Methods ◽  
Detailed Comparison ◽  
Synthesis And Crystal Structure ◽  
Full Matrix ◽  
Cyclopropyl Ketone ◽  
R Value

(3aRS,4RS,6RS,8aSR)-5-Methyleneoctahydro-4H-3a,6-methanoazulene-4-carboxylic acid (7) has been synthesized and a detailed comparison made between its molecular structure and that of gibberellic acid (4). Indane-5-carboxylic acid (8) was converted by an alternating sequence of reduction and isomerization into the hydrindene acid (11). The diazomethyl ketone derived from (11) was transformed to cyclopropyl ketone (12) which was reduced by Li/NH3 with stereochemical inversion at the β-carbon to give a 1:3 mixture of ketones (13) and (14) respectively. Ketone (14) was then converted into the title acid (7) by a standard procedure. ��� Molecules of (7) crystallize in space group P2/c with a 7.782(1), b 11.055(1), c 14.559(3) Ǻ, β 116.05(1)°. The structure was solved by direct methods and refined by full-matrix least squares to a final R value of 0.053.

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