Identification of two lead perovskites, Pb2ScTaO6 and Pb(Sc0.5Nb0.5)O3, by X-ray powder diffraction patterns

1993 ◽  
Vol 8 (3) ◽  
pp. 191-193 ◽  
Author(s):  
C. Caranoni ◽  
P. Lampin ◽  
C. Boulesteix

Substituting cations in materials with the formula Pb2B′B″O6 is more or less ordered on the B sites. High-quality single crystals of Pb2ScTaO6 (PST) and Pb(Sc0.5Nb0.5)O3 (PSN) were prepared from two thermal cycles. A stoichiometric mixture of the constituent oxides was prefired at up to 1000 °C, and then crystals were grown from a PbO–B2O3–PbF2 flux mixture, starting at a temperature of 1100 °C for PSN and 1200 °C for PST. At room temperature, X-ray examination showed that PSN had a perovskite structure with a cubic unit-cell and a refined parameter a = 4.080(1 ) Å, space group Pm3m and Z = 1, whereas PST formed a well-ordered superlattice with a = 8.136(1) Å, Z = 4 and space group Fm3m. In each case a fully indexed powder pattern is presented. The degree of order is estimated to be close to 80% for PST and less than 10% for PSN.

2018 ◽  
Vol 74 (7) ◽  
pp. 1006-1009 ◽  
Author(s):  
Matthias Weil

Single crystals of Ba2K2Te2O9(dibarium dipotassium nonaoxidoditellurate), (I), Ba2KNaTe2O9(dibarium potassium sodium nonaoxidoditellurate), (II), and Ba2CaTeO6(dibarium calcium hexaoxidotellurate), (III), were obtained from KNO3/KI or KNO3/NaNO3flux syntheses in platinum crucibles for (I) and (II), or porcelain crucibles for (III). (I) and (II) are isotypic and are members of triple perovskites with general formulaA2[12co]A′[12co]B2[6o]B′[6o]O9. They crystallize in the 6H-BaTiO3structure family in space-group typeP63/mmc, with theA,A′,BandB′ sites being occupied by K, Ba, Te and a second Ba in (I), and in (II) by mixed-occupied (Ba/K), Ba, Te and Na sites, respectively. (III) adopts theA2[12co]B′[6o]B′′[6o]O6double perovskite structure in space-group typeFm-3m, with Ba, Ca and Te located on theA,B′ andB′′sites, respectively. The current refinement of (III) is based on single-crystal X-ray data. It confirms the previous refinement from X-ray powder diffraction data [Fuet al.(2008).J. Solid State Chem.181, 2523–2529], but with higher precision.


1997 ◽  
Vol 12 (3) ◽  
pp. 134-135
Author(s):  
Liangqin Nong ◽  
Lingmin Zeng ◽  
Jianmin Hao

The compound DyNiSn has been studied by X-ray powder diffraction. The X-ray diffraction patterns for this compound at room temperature are reported. DyNiSn is orthorhombic with lattice parameters a=7.1018(1) Å, b=7.6599(2) Å, c=4.4461(2) Å, space group Pna21 and 4 formula units of DyNiSn in unit cell. The Smith and Snyder Figure-of-Merit F30 for this powder pattern is 26.7(0.0178,63).


1999 ◽  
Vol 14 (4) ◽  
pp. 280-283 ◽  
Author(s):  
A. Rafalska-Łasocha ◽  
W. Łasocha ◽  
M. Michalec

The X-ray powder diffraction patterns of anilinium trimolybdate tetrahydrate, (C6H5NH3)2Mo3O10·4H2O, and anilinium trimolybdate dihyhydrate, (C6H5NH3)2Mo3O10·2H2O, have been measured in room temperature. The unit cell parameters were refined to a=11.0670(7) Å, b=7.6116(8) Å, c=25.554(3) Å, space group Pnma(62) and a=17.560(2) Å, b=7.5621(6) Å, c=16.284(2) Å, β=108.54(1)°, space group P21(4) or P21/m(11) for orthorhombic anilinium trimolybdate tetrahydrate and monoclinic anilinium trimolybdate dihydrate, respectively.


2004 ◽  
Vol 19 (4) ◽  
pp. 378-384
Author(s):  
A. Rafalska-Lasocha ◽  
M. Grzywa ◽  
B. Włodarczyk-Gajda ◽  
W. Lasocha

The X-ray diffraction patterns of two organic acids 1-naphthalenesulfonic acid dihydrate and 2-naphthalenesulfonic acid hydrate were measured at room temperature. Complexes of these acids with 1,8-bis(dimethylamino)naphthalene (DMAN) were synthesized, purified and investigated by means of X-ray powder diffraction. 1-Naphthalenesulfonic acid dihydrate as well as its complex with 1,8-bis(dimethylamino)naphthalene crystallize in the monoclinic system with unit cell parameters refined to a=0.91531(8) nm, b=0.7919(1) nm, c=0.8184(1) nm, β=101.618(9)° space group P21/m (11) and a=1.7781(4) nm, b=2.0122(4) nm, c=1.2337(2) nm, β=96.54(3)°, space group C2/m (12), respectively. 2-Naphthalenesulfonic acid hydrate crystallizes in the orthorhombic system with a=2.2749(3) nm, b=0.7745(1) nm, c=0.591 36(9) nm, space group Pnma, whereas its complex with 1,8-bis(dimethylamino)naphthalene crystallizes in the triclinic system a=1.3969(6) nm, b=1.4292(5) nm, c=1.1741(6) nm, α=90.93(3)°, β=98.14(3)°, γ=113.93(3)°, space group P-1 (2).


2003 ◽  
Vol 18 (3) ◽  
pp. 266-268
Author(s):  
A. Rafalska-Łasocha ◽  
W. Łasocha

The X-ray powder diffraction patterns of two liquid aniline derivatives o-chloroaniline, and m-chloroaniline were measured at 250 °K in a low temperature chamber. Both compounds crystallize in the orthorhombic system with the unit cell parameters refined to a=1.8391(3) nm, b=1.0357(2) nm, c=0.6092(1) nm, space group Pmmm(47) and a=0.450 39(9) nm, b=1.9820(4) nm, c=1.2699(4) nm, space group Pcca(54) for o-chloroaniline and m-chloroaniline, respectively. Investigated at room temperature, 2,6-dichloroaniline crystallizes in the monoclinic system, space group P21/c(14), a=1.1329(2) nm, b=0.41093(8) nm, c=1.5445(3) nm, α=γ=90° β=99.96(2)°.


1992 ◽  
Vol 7 (4) ◽  
pp. 228-230 ◽  
Author(s):  
Bokhimi

AbstractThe crystalline structure of the M2CuWO6 phases with M = Ba or Sr was obtained from X-ray powder diffraction at room temperature with CuKα radiation. The phases are isostructural with tetragonal unit cells, space group I4/m and Z = 2. The parameters for the Sr2CuWO6 phase are: Mr = 518.6, a = 5.42693(5) Å, c = 8.4087(1) Å, V = 247.65(1) Å3, Dx = 6.954 Mg/m3, μ = 77.75 mm−1, F(000) = 454, R = 0.0375 for 24 reflections; the parameters for the Ba2CuWO6 phase are: Mr = 618.1, a = 5.56392(8) Å, c = 8.6274(1) Å, V = 267.08(1) Å3, Dx = 7.683 Mg/m3, μ = 157.0 mm−1, F(000) = 526, R = 0.0506 for 27 reflections. Cell parameters were obtained from Rietveld refinement. The crystalline structure is based on the perovskite structure. It is laminar with ordered alternating WO6 deformed octahedra and CuO2 planar squares along the [110] direction, joined by corners and rotated perpendicular to the [001] direction. The samples are electrica insulators.


2004 ◽  
Vol 19 (3) ◽  
pp. 292-295
Author(s):  
A. Rafalska-Lasocha ◽  
B. Włodarczyk-Gajda ◽  
M. Grzywa ◽  
W. Lasocha

The X-ray powder diffraction patterns of three phenol derivatives—2-chlorophenol, 2,6-dichloro-4-nitrophenol, and 2,6-dichloro-phenoloindophenol tetrahydrate—were collected and the lattice parameters of these compounds were determined. The measurement for 2-chlorophenol was carried out at 250 K in a low-temperature chamber; this compound crystallizes in hexagonal system with a=1.59602(8) nm, c=0.59761(7) nm, space group P6 or P63/m. Investigated at room temperature, 2,6-dichloro-4-nitrophenol and 2,6-dichloro-phenoloindophenol tetrahydrate crystallize in the triclinic system with the unit cell parameters refined to a=0.8169(2) nm, b=1.6637(6) nm, c=0.7440(1) nm, α=96.6(3)°, β=116.19(2)°, γ=78.68°, and space group P-1(2), and a=0.7792(3) nm, b=1.2795(4) nm, c=0.7256(3) nm, α=91.17(5)°, β=96.93(4)°, γ=85.41(3)°, and space group P-1(2), respectively. © 2004 International Centre for Diffraction Data.


2003 ◽  
Vol 18 (2) ◽  
pp. 128-134 ◽  
Author(s):  
A. Le Bail ◽  
A.-M. Mercier

The crystal structures of the chiolite-related room temperature phases α-Na5M3F14 (MIII=Cr,Fe,Ga) are determined. For all of them, the space group is P21/n, Z=2; a=10.5096(3) Å, b=7.2253(2) Å, c=7.2713(2) Å, β=90.6753(7)° (M=Cr); a=10.4342(7) Å, b=7.3418(6) Å, c=7.4023(6) Å, β=90.799(5)° (M=Fe), and a=10.4052(1) Å, b=7.2251(1) Å, c=7.2689(1), β=90.6640(4)° (M=Ga). Rietveld refinements produce final RF factors 0.036, 0.033, and 0.035, and RWP factors, 0.125, 0.116, and 0.096, for MIII=Cr, Fe, and Ga, respectively. The MF6 polyhedra in the defective isolated perovskite-like layers deviate very few from perfect octahedra. Subtle octahedra tiltings lead to the symmetry decrease from the P4/mnc space group adopted by the Na5Al3F14 chiolite aristotype to the P21/n space group adopted by the title series. Facile twinning precluded till now the precise characterization of these compounds.


1964 ◽  
Vol 42 (10) ◽  
pp. 1886-1889 ◽  
Author(s):  
B. Swaroop ◽  
S. N. Flengas

The crystal structure of zirconium trichloride was determined from X-ray diffraction patterns. Zirconium trichloride belongs to the [Formula: see text]space group. The dimensions of the main cell at room temperature are: a = 5.961 ± 0.005 Å and c = 9.669 ± 0.005 Å.The density of zirconium trichloride was measured and gave the value of 2.281 ± 0.075 g/cm3 while, from the X-ray calculations, the value was found to be 2.205 g/cm3.


2014 ◽  
Vol 950 ◽  
pp. 48-52
Author(s):  
De Gui Li ◽  
Ming Qin ◽  
Liu Qing Liang ◽  
Zhao Lu ◽  
Shu Hui Liu ◽  
...  

The Al2M3Y(M=Cu, Ni) compound was synthesized by arc melting under argon atmosphere. The high-quality powder X-ray diffraction data of Al2M3Y have been presented. The refinement of the X-ray diffraction patterns for the Al2M3Y compound show that the Al2M3Y has hexagonal structure, space groupP6/mmm(No.191), with a = b = 5.1618(2) Å, c = 4.1434(1) Å,V= 95.6 Å3,Z= 1,ڑx= 5.7922 g/cm3,F30= 155.5(0.0057, 34), RIR = 2.31 for Al2Cu3Y, and with a = b = 5.0399(1) Å, c = 4.0726(1) Å,V= 89.59 Å3,Z= 1,ڑx= 5.9118 g/cm3,F30= 135.7(0.0072, 30), RIR = 2.54 for Al2Ni3Y.


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