A Method of Determining the Axial Ratio of a Crystal from X-Ray Diffraction Data: The Axial Ratio and Lattice Constants of Zinc Oxide

Science ◽  
1929 ◽  
Vol 70 (1808) ◽  
pp. 196-198
Author(s):  
M. Luther Fuller
2010 ◽  
Vol 163 ◽  
pp. 173-176
Author(s):  
Lucjan Pająk ◽  
E. Olszewska ◽  
Stanislaw Pikus ◽  
Grzegorz Dercz ◽  
Józef Rasek

In the present work X-ray studies were performed on annealed Fe78Nb2B20 amorphous alloy prepared by melt-spinning technique. All the samples were annealed in vacuum for 1 hour at temperatures up to 800°C. For the studied alloy -Fe and Fe2B are the stable, crystalline phases. The -Fe crystallized as the first crystalline phase in the sample annealed at 350°C. On the other hand, metastable Fe3B phase appeared to be stable during annealing in 425-800°C temperature range. The best fitting of the experimental X-ray data to as jet available ICDD files was obtained for Ni3P type structure (39-1315 – S.G.: I (82)). New, experimental powder diffraction data for metastable Fe3B phase prepared according to ICDD standards were elaborated for the sample annealed at 600°C. For this sample the best agreement between the calculated values of lattice constants and positions of experimental diffraction lines was obtained. The X-ray data were collected using X-Pert Philips diffractometer equipped with curved graphite monochromator on diffracted beam. The Treor program was applied for the analysis of X-ray diffraction data.


1985 ◽  
Vol 40 (1) ◽  
pp. 13-18 ◽  
Author(s):  
Kay Jansen ◽  
Kurt Dehnicke ◽  
Dieter Fenske

The syntheses and IR spectra of the complexes [Mo2(O2C-Ph)4X2]2⊖ with X = N3, CI, Br and the counter ion PPh4⊕ are reported. The azido and the bromo complexes are obtained from a solution of [Mo2(O2CPh)4] with PPh4N3 in pyridine or by reaction with PPh4Br in CH2Br2, respectively. When (PPh4)2[Mo2(O2CPh)4(N3)2] is dissolved in CH2Cl2, nitrogen is evolved and the complex with X = CI is obtained. The crystal structure of (PPh4)2[Mo2(O2CPh)4Cl2] · 2CH2Cl2 was determined from X-ray diffraction data (5676 observed independent reflexions, R = 0.042). It crystallizes in the monoclinic space group P21/n with four formula units per unit cell; the lattice constants are a = 1549, b = 1400, c = 1648 pm, β = 94.6°. The centrosymmetric [Mo2(O2CPh)4Cl2]2⊖ ion has a rather short Mo-Mo bond of 213 pm, whereas the MoCl bonds are very long (288 pm)


2017 ◽  
Vol 81 (2) ◽  
pp. 251-272 ◽  
Author(s):  
M. Lacalamita ◽  
E. Mesto ◽  
E. Kaneva ◽  
F. Scordari ◽  
G. Pedrazzi ◽  
...  

AbstractThe structures of tokkoite, K2Ca4[Si7O18OH](OH,F) and tinaksite, K2Ca2NaTi[Si7O18OH]O from the Murun massif (Russia) were refined from single-crystal X-ray diffraction data in the triclinic space group P1̄. Average crystallographic data are a ≈ 10.423, b ≈ 12.477, c ≈ 7.112 Å, α ≈ 89.92°, β ≈ 99.68°, γ ≈ 92.97°, V ≈ 910.5 Å3 for tokkoite; a ≈ 10.373, b ≈ 12.176, c ≈ 7.057 Å, α ≈ 90.82°, β ≈ 99.22°, γ ≈ 92.80°, V ≈ 878.5 Å3 for tinaksite. The substantial similarities between the geometrical parameters of the tokkoite and tinaksite structures led us to conclude that the two minerals are isostructural. However, major differences of tokkoite with respect to tinaksite are larger lattice constants, especially concerning the b parameter, longer <M–O> distances, especially <M1–O>; larger values of the M1–M3 and O20–O2 bond lengths, and a stronger distortion of the M1 polyhedron. Mössbauer analysis showed that significant trivalent iron is present, VIFe3+ 40.0(7)% in tokkoite and 12.8(3)% in tinaksite. It is confirmed that 2Ca(M1+M2)2+ + (F,OH)(O20)–↔ Ti(M1)4+ + Na(M2)+ + O(O20)– is the exchange reaction that describes the relation between tokkoite and tinaksite. In addition, this exchange reaction causes local stress involving mainly the M1 site and its interaction with the M2 and M3 sites.


1985 ◽  
Vol 40 (3) ◽  
pp. 443-446 ◽  
Author(s):  
Udo Demant ◽  
Elke Conradi ◽  
Ulrich Müller ◽  
Kurt Dehnicke

[HC(NH2)2]3FeCl6 was obtained together with other products from the reaction of S4N4 with HCl in H2CCl2 in the presence of FeCl3. Its crystal structure was determined from X-ray diffraction data (473 independent observed reflexions, R = 0.047). Lattice constants: a = 961.6, c = 876.4 pm; tetragonal, space group P42/m, Z = 2. Of the two crystallographically independent formamidinium ions HC(NH2)2⊕, one exhibits positional disorder; the other one has C-N bond lengths of 128 pm. The FeCl63⊖ ions have symmetry C2h, but the deviation from Oh is small.


1984 ◽  
Vol 39 (12) ◽  
pp. 1686-1695 ◽  
Author(s):  
Jürgen Hanich ◽  
Magda Krestel ◽  
Ulrich Müller ◽  
Kurt Dehnicke ◽  
Dieter Rehder

An improved synthesis for [VCl2(N3S2)]∞, was found in the reaction of VOCl3 with (NSCl)3; when the reaction is performed in H2CCl2 and (NSCl)3 is used in excess, the thiazyl-solvate [VCl2(N3S2) · NSCl]2 is obtained. [VCl2(N3S2)] reacts with AsPh4Cl to form (AsPh4)2[VCl3(N 3S2)]2; this reacts with AgN3 in CH2Cl2 suspension to yield (AsPh4)2[V (N3)3(N3S2)]2 · CH2Cl2. The compounds were characterized by their IR and 51V NMR spectra. The latter are compared with new 51V NMR data for [VO2Cl2]⊖ and [VOCl4]⊖ ; a decrease of 51V shielding in the order [VO2Cl2]⊖ > [VOCl4]⊖ > [VX3(N3S2)]22⊖ (X - N3 > Cl) is found, which is interpreted in terms of increasing polarizability of the ligands and of ring contributions to the extreme deshielding observed with the thiazenovanadates.The crystal structure of (AsPh4)2[V(N3)3(N3S2)]2 · CH2Cl2 was determined from X-ray diffraction data (1496 observed reflexions, R = 0.058). It crystallizes in the triclinic space group P 1̄ with one formula unit per unit cell and with the lattice constants a - 1087, b = 1317, c = 1350 pm, α = 58.8, β = 85.9, γ = 68.0°. The structure consists of AsPh4⊕ ions, CH2Cl2 molecules and centrosymmetric [V(N3)3(N3S2)]22⊖ anions. In the latter. N3S2 ligands are bonded to the V atoms in a chelate manner with short V = N bonds (189 and 172 pm) forming planar VN3S2 rings. The dimerization is accomplished by V -N donor-acceptor interactions (224 pm) involving one N atom of each VN3S2 ring. The vanadium coordination number of 6 is com pleted by three azido groups with V -N bond distances of 200 to 204 pm.


1984 ◽  
Vol 39 (2) ◽  
pp. 213-216 ◽  
Author(s):  
Roland E. Schmidt ◽  
Werner Massa

Based on single crystal X-ray diffraction data the crystal structure of tricarbonyl(2,6-dwmbutyl- pyridine)chromium(0) has been determined at 200 K: space group P 21/n, Z = 4, lattice constants a = 680.6(5), b - 1383.3(10), c = 1763.0(16) pm, β = 96.53(8)°, refinement to Rw - 0.048 for 1672 independent reflections with FO > 2 σ. The chromium atom is η6π6- bonded to the essentially planar pyridine ring (Cr-C: 219-222 pm, Cr-N: 221 pm). The CO ligands show “eclipsed” orientation with respect to the 2, 4 and 6 position of the pyridine ring. Two CO groups fit into the gaps formed by two methyl groups of the tert-butyl substituents in 2 and 6 position, respectively. The results are discussed in context with related arene and λ3-phosphorine complexes


Author(s):  
T. Tagai ◽  
H. Takeda ◽  
T. Fukuda

AbstractThe superstructure of tetrataenite, FeNi from the Saint Severin meteorite was determined using X-ray diffraction data from a conventional X-ray source and synchrotron radiation. Lattice constants of tetrataenite show clearly tetragonal symmetry;


2009 ◽  
Vol 24 (1) ◽  
pp. 53-55
Author(s):  
M. Alizadeh ◽  
K. Ahmadi ◽  
A. Maghsoudipour

X-ray powder diffraction data for three new bismuth yttrium ytterbium oxide compounds synthesized by solid-state reaction method are reported. The unit-cell dimensions were determined from X-ray diffraction method using Cu Kα radiation and evaluated by indexing programs. The cubic δ-Bi2O3 phase was identified to be the sole crystalline phase in Bi0.82Y0.09Yb0.09O1.5, Bi0.82Y0.12Yb0.06O1.5, and Bi0.82Y0.06Yb0.12O1.5 with lattice constants of a=5.5110(3), 5.5154(2), and 5.5113(2) Å, respectively.


2008 ◽  
Vol 23 (3) ◽  
pp. 255-258
Author(s):  
M. Alizadeh ◽  
K. Ahmadi ◽  
A. Maghsudipour ◽  
F. Moztarzadeh

X-ray powder diffraction data for five new bismuth yttrium gadolinium oxide compounds synthesized by solid state reaction method are reported. The unit cell dimensions were determined from X-ray diffraction methods, using CuKα radiation, and evaluated by indexing programs. The cubic phase was the sole crystalline phase detected by X-ray diffraction analysis in Bi0.88Y0.06Gd0.06O1.5, Bi0.88Y0.08Gd0.04O1.5, Bi0.82Y0.09Gd0.09O1.5, Bi0.82Y0.12Gd0.06O1.5, and Bi0.82Y0.06Gd0.12O1.5 samples with lattice constants of a=5.5371(1) Å, a=5.5368(1) Å, a=5.5303(2) Å, a=5.53487(8) Å, and a=5.5279(1) Å, respectively. The results are in good agreement with those reported for bismuth yttrium oxide (Bi0.75Y0.25)O1.5 (PDF 01-084-1450).


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