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.

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.

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 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.

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.

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.

Crystal and molecular structure of hexadecamethylcyclooctaphosphazene, (NPMe2)8

1977 ◽  
Vol 55 (13) ◽  
pp. 2530-2533 ◽  
Author(s):  
Richard T. Oakley ◽  
Norman L. Paddock ◽  
Steven J. Rettig ◽  
James Trotter
Keyword(s):  
Molecular Structure ◽  
Least Squares ◽  
Crystal And Molecular Structure ◽  
Direct Methods ◽  
Membered Ring ◽  
Weighted Mean ◽  
Full Matrix ◽  
Space Group ◽  
Bond Lengths ◽  
The Mean

Crystals of hexadecamethylcyclooctaphosphazene are tetragonal, a = 13.637(1), c = 8.215(1) Å, Z = 2, space group P4/n. The structure was solved by direct methods and was refined by full-matrix least-squares procedures to a final R of 0.033 and Rw of 0.032 for 1306 reflections with I ≥ 4σ(I) The molecule has crystallographic fourfold (C4) symmetry with weighted mean bond lengths P—N, 1.590(13), P—C, 1.811(2), and C—H, 0.95(2) Å (those not involving hydrogen have been corrected for libration, rms deviations from the mean are given in parentheses). Angles in the 16-membered ring are 119.2(1) and 115.1(1)° at P and 131.5(1) and 148.2(1)° at N.

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.

The preparation and the crystal and molecular structure of tetradecamethylcycloheptaphosphazene, (NPMe2)7

1977 ◽  
Vol 55 (2) ◽  
pp. 304-309 ◽  
Author(s):  
Keith D. Gallicano ◽  
Richard T. Oakley ◽  
Norman L. Paddock ◽  
Steven J. Rettig ◽  
James Trotter
Keyword(s):  
Molecular Structure ◽  
Least Squares ◽  
Crystal And Molecular Structure ◽  
Direct Methods ◽  
Membered Ring ◽  
Full Matrix ◽  
Space Group ◽  
Bond Lengths ◽  
The Mean

The preparation of tetradecamethylcycloheptaphosphazene, by the methylation of the corresponding fluorophosphazene (NPF2)7 with methylmagnesium bromide, is reported. Crystals of tetradecamethylcycloheptaphosphazene are monoclinic, a = 13.160(1), b = 11.685(1), c = 18.576(1) Å, (β = 108.333(5)°, Z = 4, space group C2/c. The structure was solved by direct methods and was refined by full-matrix least squares procedures to a final R of 0.046 and Rw of 0.063 for 2568 reflections with I ≥ 3σ(I). The molecule has crystallographic C2 symmetry with mean bond lengths (rms deviations from the mean in parentheses, bonds not involving hydrogen have been corrected for libration) P—N, 1.592(6), P—C, 1.804(11), and C—H, 0.94(7) Å, and mean angles in the 14-membered ring are 132.9° at N and 117.1° at P.

Crystal and molecular structures of 2,2,4,4,6,8,8-heptamethyl-6-methylamino-1,3,5-triaza-2,4,6,8(PV)-tetraphosphorin and 2,2,4,4,6,8,8-heptamethyl-6-methylamino-7-benzoyl-1,3,5-triaza-2,4,6,8(PV)-tetraphosphorin

1978 ◽  
Vol 56 (22) ◽  
pp. 2833-2843 ◽  
Author(s):  
Harry P. Calhoun ◽  
Richard T. Oakley ◽  
Norman L. Paddock ◽  
Steven J. Rettig ◽  
James Trotter
Keyword(s):  
Least Squares ◽  
Direct Methods ◽  
Molecular Structures ◽  
Full Matrix ◽  
Space Group ◽  
Bond Lengths ◽  
Crystal And Molecular Structures ◽  
Out Of Plane ◽  
The Mean

Crystals of 2,2,4,4,6,8,8-heptamethyl-6-methylamino-1,3,5-triaza-2,4,6,8(PV)-tetraphosphorin are monoclinic, a = 11.639(4), b = 11.957(7), c = 12.114(4) Å, β = 94.07(2) °, Z = 4, space group P21/n. The structure was solved by direct methods and was refined by full-matrix least-squares procedures to R = 0.032 and Rw of 0.041 for 2012 reflections with I ≥ 3σ(I). Crystals of 2,2,4,4,6,8,8-heptamethyl-6-methylamino-7-benzoyl-1,3,5-triaza-2,4,6,8(PV)-tetraphosphorin are triclinic, a = 15.513(1), b = 8.422(1), c = 8.933(1) Å, α = 89.24(1), β = 100.18(1), γ = 107.30(1) °, Z = 2, space group [Formula: see text]. The structure was solved by Patterson and Fourier syntheses and was refined to a final R of 0.041 and Rw of 0.044 for 3654 reflections with I ≥ 3σ(I). The eight-membered P4N3C rings in both structures hâve 'tub' conformations. The mean bond lengths (corrected for libration) are: P—N(endo), 1.609(9), P—N(exo), 1.679(2), P—C(endo), 1.717(2), and P—C(exo), 1.815(8) Å for Me7(MeNH)P4N3CH and 1.595(4), 1.655(2), 1.763(4), and 1.804(5) Å respectively for Me7(MeNH)P4N3CC(O)Ph. The near-equivalence of the endocyclic P—N bond lengths in the azaphosphorins is discussed in terms of opposing changes in the in-plane and out-of-plane Π-systems.

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