THE CRYSTAL STRUCTURE OF α-Zn3(PO4)2

1965 ◽  
Vol 43 (2) ◽  
pp. 436-445 ◽  
Author(s):  
Crispin Calvo

α-Zn3(PO4)2 crystallized in the monoclinic space group C2/c with lattice parameters a = 8.14 ± 0.02 Å, b = 5.63 ± 0.01 Å, c = 15.04 ± 0.04 Å, β = 105°08′ ± 05′, and Z = 4. The cations are found in two types of tetrahedrally coordinated sites. One-third of the cations lie on twofold axes within an oxygen tetrahedron. The remaining cations are found in a pair of edge-sharing oxygen atom tetrahedra. The green emission of Mn++ in α-Zn3(PO4)2 is consistent with Mn++ substituting for Zn++ in either tetrahedral site.

1967 ◽  
Vol 45 (20) ◽  
pp. 2303-2316 ◽  
Author(s):  
J. S. Stephens ◽  
C. Calvo

β-Zn3(PO4)2 crystallizes in the monoclinic space group P 21/c with lattice parameters, a = 9.393(3) Å, b = 9.170(6) Å, c = 8.686(3) Å, β = 125.73(10)°, and Z = 4. The three independent cations are strongly ligated to 4, 5, and 5 oxygen atoms, with average Zn—O bond distances of 1.98 ± 0.09 Å, 2.10 ± 0.10 Å, and 2.08 ± 0.13 Å respectively. In addition there are two longer Zn—O distances of 2.51 Å and 2.55 Å in this structure. The PO4 groups exist as independent, nearly regular tetrahedra, with each oxygen atom ligated to two cations. Unlike the structures found for the α and γ phases of Zn3(PO4)2, which contain ribbons and sheets respectively as the basic cation coordination motif, the structure of β-Zn3(PO4)2 contains interconnected sheets.


1967 ◽  
Vol 45 (20) ◽  
pp. 2297-2302 ◽  
Author(s):  
P. K. L. Au ◽  
C. Calvo

Cadmium pyrovanadate crystallizes in the C2/m space group with lattice parameters a = 7.088(5) Å, b = 9.091(5) Å, c = 4.963(5) Å, β = 103°21(5)′, and z = 2. This crystal is an isostructure of the mineral thortveitite and thus the anion consists of a pair of centrosymmetrically related corner-sharing VO4 tetrahedra while the cation resides within a distorted octahedron of oxygen atoms. The anion has a linear V—O—V group, but, as with the isostructural pyrophosphates, the central oxygen atom shows an anomalously high thermal activity. The V—O bond distances are 1.76 Å for the inner bond and 1.70 Å for the terminal bond. The bond angles about the anion and cation are similar to those found for the other analogues of thortveitite.


1988 ◽  
Vol 43 (8) ◽  
pp. 1029-1032 ◽  
Author(s):  
Johannes Beck

Abstract(Cp)Mo(CO)2(tolN5tol) is formed in the reaction of (Cp)Mo(CO)3Cl with tolNN(NH)NNtol and NaOH in ethanol. It forms red platelike crystals from THF/hexane which crystallize in the monoclinic space group P21/n with the lattice parameters a = 765.6(2), b = 2372.3(3), c = 1149.4(2) pm, β = 97.06(2)°, Z = 4. The structure consists of monomeric complexes. The pentaazadienido ligand chelates with its nitrogen atoms N1 and N3 the Mo atom of a (Cp)Mo(CO)2 unit. The nitrogen atom N5 is not coordinated to the metal atom. Although asymmetrically bonded, the all trans N5 zig zag chain is planar. The N -N distances in the four membered chelate ring are nearly equal (N1 - N2 = 131.0 and N2 - N3 = 132.6 pm)


1993 ◽  
Vol 48 (3) ◽  
pp. 313-317 ◽  
Author(s):  
Ayhan Elmali ◽  
Yalcin Elerman ◽  
Ingrid Svoboda ◽  
Hartmut Fuess ◽  
Klaus Griesar ◽  
...  

μ-Oxo-bis[N ,N '-o-phenylene-di(salicylaldiminato)iron(III)] was synthesized in dioxane solvent and its crystal structure determined. [C2OH14N ,OiFe]-,O · (C4H8O2), monoclinic, space group P21/ c ,a = 14.650(2), b = 18.990(1), c = 13.296(1) Å, β = 76.080(7), V = 3590.3 Å3, Z = 4. Two iron (III) atoms in square pyramidal pentacoordination are bridged by an oxygen atom with an Fe - O - Fe angle of 145 and a Fe-Fe distance of 3.409(1) Å. The iron (III) centers are antiferrommagnetically coupled (J = -9 8 .5 cm-1), as derived from temperature-dependent magnetic susceptibility measurements in the range 4.2 to 286.5 K.


1985 ◽  
Vol 40 (8) ◽  
pp. 1073-1076 ◽  
Author(s):  
Johannes Beck ◽  
Eberhard Schweda ◽  
Joachim Strähle

AbstractMoN(N3)2Cl(terpy) is formed by the reaction of MoCl4(C2H5CN)2 with (CH3)3SiN3 and subsequent addition of terpy. This complex appears also as the main product o f the heterogeneous reaction between MoCl3(terpy) and (CH3)3SiN3. It crystallizes in the monoclinic space group P 21/c with the lattice parameters a = 875.5, b = 1041.4, c = 1891.3 pm, β = 97.00°, Z = 4. The central Mo atom is seven-coordinated in the form of a slightly distorted pentagonal bipyramid, the nitrido and chloro ligands being in axial positions. The triply bonded nitrido ligand ( Mo - N 1 = 166.2 pm) causes a strong trans effect, resulting in a long Mo-Cl distance of 271.9 pm.


Author(s):  
C.W. Lehmann ◽  
A. Fürstner ◽  
Th. Müller

The structure of a tricolorin A derivative (11S)-11-[[4,6-O-benzylidene-β-D-glucopyranosyl-(1 → 2)-3,4-O-isopropylidene-β-D-fucopyranosyl]oxy]hexadecanoic acid 3gluc-lactone 2, a member of the resin glycosides, has been determined. This crystal structure is the first example for this class of natural products. At 100 K the lattice parameters in monoclinic space group P2


1992 ◽  
Vol 45 (9) ◽  
pp. 1415 ◽  
Author(s):  
HJ Rossell ◽  
M Leblanc ◽  
G Ferey ◽  
DJM Bevan ◽  
DJ Simpson ◽  
...  

Bi2Te4O11 is monoclinic, space group P21/n; the lattice parameters derived from a Guinier powder pattern ( Si standard) are: a = 6.9909(3), b = 7.9593(3), c = 18.8963(8) � , β = 95.176(3)�, Z = 4, V = 1047.15 �. The structure was solved independently from both single-crystal X-ray data and a combination of X-ray and neutron powder data. It is an anion-deficient superstructure of fluorite in which can be recognized the ordered intergrowth of fluorite-type Bi2Te2O7 and rutile-type Te2O4. Lone-pair electrons are stereochemically active.


2014 ◽  
Vol 69 (3) ◽  
pp. 294-298 ◽  
Author(s):  
Olaf Reckeweg ◽  
Armin Schulz ◽  
Francis J. DiSalvo

Transparent and colorless single crystals of Yb26B12O57 were obtained by reacting Yb2O3 and B powder at 1000 °C in the presence of a KCl flux for 24 h in silica-jacketed Nb ampoules and subsequent removal of the flux by washing with water. Yb26B12O57 crystallizes in the monoclinic space group C2/m (no. 12, Z = 1) with the lattice parameters a = 2454:1(3), b = 357:78(4), c = 1426:7(2) pm and β = 115:111(6)°, and its structure differs slightly from that of a known compound with the same stoichiometry. Raman spectra of single crystals of the title compound were recorded and compared to those of known borate compounds


1977 ◽  
Vol 55 (10) ◽  
pp. 1673-1679 ◽  
Author(s):  
Nora Middlemiss ◽  
Frank Hawthorne ◽  
Crispin Calvo

Vanadium(III) tris(metaphosphate), V(PO3)3, crystallizes in the monoclinic space group Ic with lattice parameters a = 10.615(2), b = 19.095(4), c = 9.432(1) Å, β = 97.94(1)° with Z = 12. The equivalent parameters in the standard space group Cc are a = 13.189(1), b = 19.095(4), c = 9.432(1) Å, and β = 127.15(1)°. The structure was refined by full-matrix least-squares to an R = 0.091 (Rω = 0.065) utilizing 2467 reflections with the atomic positions and their isotropic vibration amplitudes as parameters. The structure consists of infinite chains of PO4 tetrahedra sharing corners with each other and bridged by VO6 octahedra. All oxygen atoms are shared between just two cations. The average [Formula: see text] bond is 1.581 Å while the average of those shared with vanadium is 1.483 Å. The VO6 group is moderately distorted, with differences of less than 0.06 Å between the longest and shortest V—O bond lengths in any of the three distinct VO6 groups. The average V—O bond lengths for the three VO6 groups are 1.995, 1.991, and 1.987 Å. A marked superlattice effect based on a cell with b/3 is noted.


2005 ◽  
Vol 20 (1) ◽  
pp. 7-13 ◽  
Author(s):  
K. S. Knight ◽  
C. N. W. Darlington ◽  
I. G. Wood

The crystal structure of the perovskite phase KCaF3 has been redetermined at 4.2 and 300 K using powder neutron diffraction collected at the highest resolution. At both temperatures the phase was found to be orthorhombic in space group Pnma, with lattice parameters a=0.622 879(5) nm, b=0.870 031(7) nm, c=0.611 210(5) nm at 4.2 K, and a=0.621 488(6) nm, b=0.876 360(8) nm, c=0.616 481(6) nm at 300 K. The CaF6 octahedron is regular at both temperatures with octahedral rotations of 9.6° and 13.2° for the in-phase and anti-phase tilts, respectively, at 4.2 K. No evidence was found to support the recent revision of the space group from Pnma to the monoclinic space group B21∕m.


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