Precise lattice constants determination of cubic crystals from x-ray powder diffractometric measurements

1985 ◽  
Vol 37 (3) ◽  
pp. 187-189 ◽  
Author(s):  
N. A. Razik
Keyword(s):  
Cubic Crystals ◽  
X Ray ◽  
Lattice Constants

YLiSn — eine ternäre Verbindung mit verzerrtem Li-Sn-Wurtzitgerüst / YLiSn - a Ternary Compound with Distorted Li - Sn - Wurtzit - Type Lattice

1979 ◽  
Vol 34 (8) ◽  
pp. 1165-1166 ◽  
Author(s):  
Gunter Steinberg ◽  
Hans-Uwe Schuster
Keyword(s):  
Ternary Compound ◽  
Structure Determination ◽  
Space Group ◽  
X Ray ◽  
Lattice Constants ◽  
Type Lattice

The X-ray structure determination of YLiSn showed that Li and Sn form a weakly distorted Wurtzit-type lattice, whose octahedral lacunas are occupied by Y. The lattice constants of the hoxagonally crystallizing compound are a = 929.6 pm and c = 734.6 pm, space group P 63mc, Z = 8

Absolute Präzisionsbestimmung von Gitterkonstanten an Germanium- und Aluminium-Einkristallen mit Elektroneninterferenzen

1967 ◽  
Vol 22 (1) ◽  
pp. 92-95 ◽  
Author(s):  
W. Witt
Keyword(s):  
Electron Diffraction ◽  
Lattice Constant ◽  
Bulk Material ◽  
X Ray Diffraction ◽  
Full Agreement ◽  
X Ray ◽  
Lattice Constants ◽  
Precision Determination ◽  
Subsequent Chemical

An absolute precision determination of lattice constants by electron diffraction is made with thin monocrystalline films of germanium and aluminium, having a thickness between 1000 and 5000 A. The films are prepared from the bulk material by mechanical polishing and subsequent chemical polishing or etching. The obtained values for the lattice constant α of both materials are within the accuracy Δα/α= ±3·10-5 of measurement in full agreement with the corresponding values obtained by X-ray diffraction (Smakula and Kalnajs).

Structure and Dynamics of Crystal Solvates Hexaphenylditin • 2X, X=Benzene , Toluene, Fluorobenzene , Chlorobenzene , and Aniline. An X-Ray, P(VAPOR)=ƒ(T)> and 2H NMR Study

1995 ◽  
Vol 50 (8) ◽  
pp. 758-769
Author(s):  
Karin Eckardt ◽  
Hartmut Fuess ◽  
Masakazu Hattori ◽  
Ryuichi Ikeda ◽  
Hiroshi Ohki ◽  
...  
Keyword(s):  
Benzene Molecule ◽  
Threefold Axis ◽  
X Ray ◽  
Lattice Constants ◽  
H Nmr ◽  
Structure And Dynamics ◽  
Nmr Study ◽  
Benzene Toluene ◽  
Vapor Pressure Measurements

Abstract The crystal structures of the hexaphenylditin (hpdt) solvate compounds, (C6H5)3Sn-Sn (C6H5)3 • 2X, solvent X = aniline (an), chlorobenzene (cb), fluorobenzene (fb), and toluene (to), were determined. They are isomorphous with the known benzene (be) crystal solvate compound hpdt • 2be, crystallizing in the trigonal space group R3̅, with Z=3 formula units per unit cell. The lattice constants (in pm), from X-ray powder diffraction, are: hpdt • 2an (1): a= 1170.01 (9), c = 2641.49 (20), c/a = 2.2577; hpdt • 2be (2): a = 1165.45 (5), c = 2641.30 (9), c/a = 2.2663; hpdt • 2cb (3): 0=1175.88(5), c = 2661.66(10), c/a = 2.2635; hpdt • 2fb (4): 0 = 1167.69(5), c = 2643.21 (9), c/a = 2.2636; hpdt • 2to (5): a=1182.24 (7), c = 2649.13(11), c/a = 2.2408. The single crystal structure determination of 5 leads to a = 1180.2(2), c = 2651.4 (5). The decomposition of 5 results in the monoclinic phase of hexaphenylditin. Vapor pressure measurements p=ƒ(T), 260 <̲ T/K <̲350, of the compounds have been performed and the heats of vaporization ΔHv/kJmole-1 were determined: 52.44 (1), 46.65 (2), 34.52 (3), 43.08 (4), 55.30 (5). The dynamics of the host molecules C6D6, C6D5CD3 and C6H5ND2 were studied by 2H NMR in the range 295 <̲ T/K <̲ 118. The rotation of the benzene molecule about its threefold axis is maintained till 118 K; in the case of toluene the rotation of the phenyl ring about the pseudo-threefold axis freezes in below 180 K, while the methyl group still rotates about its threefold axis till 123 K.

Die Röntgenstrukturanalyse der Pyrrolide (CH3)2Al - C4H3NCH3 und (CH3)2Ga - N(CCH3)4 / The X-Ray Structure Determination of the Pyrrolides (CH3)2Al - C4H3NCH3 and (CH3)2Ga - N(CCH3)4

1994 ◽  
Vol 49 (3) ◽  
pp. 430-433 ◽  
Author(s):  
Hans-Dieter Hausen ◽  
Jochen Tödtmann ◽  
Johann Weidlein
Keyword(s):  
Structure Determination ◽  
Unit Cell ◽  
Lattice Parameters ◽  
Metal Ring ◽  
Monoclinic Space Group ◽  
Triclinic Space Group ◽  
Space Group ◽  
X Ray ◽  
Lattice Constants

AbstractN-M ethyl-2-dimethylaluminium pyrrolide, (CH3)2Al -C4H3NCH3, crystallizes in the triclinic space group P1̄ with the lattice constants a = 700.5(1), b = 725.9(1), c = 886.8(1) pm, α = 67.69(1)°, β = 70.99(1)°, γ = 88.48(1)°, and Z = 2. This compound is isotypic with the gallium homologue [1], the shortest metal-ring contact between the two molecules of one unit cell decreases to 228.6 pm. N-dimethylgallium tetramethylpyrrolide has been synthesized from Li-N (CCH3)4 and (CH3)2GaCl. This “π-associate” crystallizes in the monoclinic space group P21/c with the lattice parameters a = 989.9(2), b = 1305.4(3), c = 878.3(2) pm, β - 112.73(1)° and 4 units per cell. Again two centrosymmetrically orientated molecules form a dimer by short (224.0 pm) intermolecular “Ga - πC ” contacts but the structure differs significant from the structure of the indium homologue [1].

Variation of cation distribution with temperature and its consequences on thermal expansion for Ca3Eu2(BO3)4

2020 ◽  
Vol 76 (4) ◽  
pp. 554-562
Author(s):  
Katarzyna M. Kosyl ◽  
Wojciech Paszkowicz ◽  
Alexey N. Shekhovtsov ◽  
Miron B. Kosmyna ◽  
Jerzy Antonowicz ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
High Temperature ◽  
High Resolution ◽  
Ambient Conditions ◽  
X Ray Diffraction ◽  
X Ray ◽  
Lattice Constants ◽  
Thermal Expansion Anisotropy ◽  
Structural Details

The structure of calcium europium orthoborate, Ca3Eu2(BO3)4, was determined using high-resolution powder X-ray diffraction data collected at the ID22 beamline (ESRF) under ambient conditions, as well as at high temperature. Rietveld refinement allowed determination of the lattice constants and structural details, including the Ca/Eu ratios at the three cationic sites and their evolution with temperature. Clear thermal expansion anisotropy was found, and slope changes of lattice-constant dependencies on temperature were observed at 923 K. Above this temperature the changes in occupation of the Ca/Eu sites occur, exhibiting a tendency towards a more uniform Eu distribution over the three Ca/Eu sites. Possible structural origins of the observed thermal expansion anisotropy are discussed.

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