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.

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.

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 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.

The crystal structure and vibrational spectra of cis-dichlorobis(cyclopropylamine)-platinum(II), PtCl2(C3H5NH2)2

1981 ◽  
Vol 59 (18) ◽  
pp. 2737-2745 ◽  
Author(s):  
Helen Elaine Howard-Lock ◽  
Colin James Lyne Lock ◽  
Graham Turner ◽  
Maruta Zvagulis
Keyword(s):  
Crystal Structure ◽  
Least Squares ◽  
Vibrational Spectra ◽  
Vibrational Analysis ◽  
Full Matrix ◽  
Space Group ◽  
Bond Lengths ◽  
Deuterated Analogue

Crystals of cis-dichlorobis(cyclopropylamine)platinum(II), PtCl2(C3H5NH2)2, are monoclinic, a = 12.770(5), b = 5.838(2), c = 15.113(6) Å, β = 104.46(3)°, Z = 4, space group P21/c. The structure was solved by Patterson and Fourier syntheses and was refined by full-matrix least-squares to R = 0.057, Rw = 0.055 for 1577 reflections with I > 3σ(I). Bond lengths and angles are normal. A vibrational analysis of the compound and its d2-deuterated analogue was performed.

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.

Crystal and molecular structure of L-prolinatodiphenylboron

1977 ◽  
Vol 55 (6) ◽  
pp. 958-965 ◽  
Author(s):  
Steven J. Rettig ◽  
James Trotter
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Least Squares ◽  
Crystal And Molecular Structure ◽  
Direct Methods ◽  
Conformational Disorder ◽  
Full Matrix ◽  
Space Group ◽  
Bond Lengths

Crystals of L-prolinatodiphenylboron are monoclinic, a = 5.9427(5), b = 14.4633(7), c = 8.9654(4) Å, β = 98.423(8)°, Z = 2, space group P21. The structure was solved by direct methods and was refined by full-matrix least-squares procedures to a final R of 0.037 and Rw of 0.053 for 1477 reflections with I ≥ 3σ(I). The proline ring exhibits conformational disorder. The crystal structure consists of discrete molecules linked by N—H … O hydrogen bonds (N … O = 2.893(3) Å) along the short a axis. Intramolecular N—B coordination occurs to form a system of two fused five-membered rings. Bond lengths (corrected for libration) are: N—B, 1.630(3), O—B, 1.529(3), O—C, 1.219(3) and 1.300(3), N—C, 1.506(3) and 1.507(3), C(sp3)–C(sp3), 1.525(4), C(sp2)—C(sp3), 1.517(3), and mean C—C(phenyl), 1.394 Å.

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 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 Structure of Thiobinupharidine

1973 ◽  
Vol 51 (17) ◽  
pp. 2810-2820 ◽  
Author(s):  
J. T. Wróbel ◽  
B. Bobeszko ◽  
T. I. Martin ◽  
D. B. MacLean ◽  
N. Krishnamachari ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Least Squares ◽  
Absolute Configuration ◽  
Spectroscopic Properties ◽  
Relative Configuration ◽  
Full Matrix ◽  
Space Group ◽  
R Value ◽  
Least Squares Techniques

The spectroscopic properties of thiobinupharidine and its isomer, neothiobinupharidine, of established structure, have been examined and compared. From this study it was possible to deduce the structure and relative configuration of the alkaloid. The structure has been firmly established and the absolute configuration determined by the study of the crystal structure of thiobinupharidine dihydrobromide dihydrate, C30H42O2N2S•2HBr•2H2O. The crystals are orthorhombic with space group C2221, a = 25.128(6), b = 9.869(2), c = 26.380(6) Å, and Z = 8. The structure was refined, using full-matrix least-squares techniques with 1934 reflections, to a final R value of 0.097. The thiobinupharidine moiety hydrogen bonds to one of two types of H2O–Br–H2O spiral chains in the structure. The tetrahydrothiophene ring is distorted from planarity, and this together with the nonequivalence of the S and C atoms in the ring causes the molecule to deviate from C2 symmetry

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.

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