Structure Refinement Induced by Deformation Twinning in 77K Tensile Cu-8%at.Al Single Crystals

2011 ◽  
Vol 674 ◽  
pp. 61-69
Author(s):  
Małgorzata Perek-Nowak ◽  
Marek S. Szczerba
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Single Crystals ◽  
Liquid Nitrogen ◽  
Structure Refinement ◽  
Deformation Twinning ◽  
Mechanical Twinning ◽  
Matrix Interface ◽  
Mode 2 ◽  
Interface Mode

In the paper the concept of structure refinement due to mechanical twinning is discussed. It is postulated that the process of structure refinement may occur when dominant crystal shear proceeds across twin-matrix interface (Mode 2). Contrary, if the crystal shear proceeds parallel to the interface (Mode 1) no condition for structure refinement is satisfied. The conditions of the structure refinement and no structure refinement are shown taking example of tensile Cu-8%at. Al single crystals of two orientations [1 4 5] and [1 1 2] tested in liquid nitrogen. The tensile characteristics are therefore divided into stages associated with the Mode 1 and Mode 2, which correspond to the fact whether refinement of single crystal structure is present or not, as it is proved by the EBSD analysis. The performed analysis showed that structure refinement consists of formation of regions of new orientations, where the most common feature is the II order twinning (the case [1 4 5]) supported by other regions of specific orientations necessary to accommodate mainly the transfer of crystal twin shear across the twin-matrix interface. Moreover, if the II order twinning plays the dominating function (the case [1 1 2]) higher order twins are to bring into operation to assure further ductility of a deformed sample.

Structure of tetrakis(dimethylamino)ethene (TDAE) at low temperatures

1995 ◽  
Vol 210 (7) ◽  
Author(s):  
J. Bruckmann ◽  
C. Krüger ◽  
H. Borrmann ◽  
A. Simon ◽  
H. Bock
Keyword(s):  
Crystal Structure ◽  
Phase Transitions ◽  
Single Crystal ◽  
Temperature Dependence ◽  
Single Crystals ◽  
Low Temperatures ◽  
Structure Refinement ◽  
Static Disorder ◽  
Structural Details ◽  
Different Temperatures

AbstractThe single crystal structure of TDAE was redetermined at different temperatures. Phase transitions are observed by warming the samples from low temperatures but never by cooling. Due to this special behavior it was possible to cool single crystals to 90 K. The data collected from such supercooled crystals resulted in a more precise and reliable structure refinement. Interesting structural details of the sterically overcrowded molecule are elucidated. The temperature dependence of the distortions of the nonplanar dimethylamino groups indicates dynamic behavior rather than static disorder.

Neutronen- und Röntgenbeugungsuntersuchungen an Pulvern und Einkristallen von Strukturverwandten des Berliner Blaus: CsMnIICrIII(CN)6 · D2O , NMe4MnII(Cr0,06,Mn0,94)III(CN)6 · 8 H2O , NMe4MnIICoIII(CN)6 · 8 H20 , Mn3II[MnIII(CN)6]2 · 15 H2O und Cd3[FeIII(CN)6]2 · 15 H2O / Neutron and X-Ray Diffraction Studies on Powders and Single Crystals of Compounds Structurally Related to Prussian Blue: CsMnIICrIII(CN)6 · D2O, NMe4MnII(Cr0,06Mn0,94)III(CN)6 · 8 H2O, NMe4MnIICoIII(CN)6 · 8 H2O, Mn3II[MnIII(CN)6]2 · 15 H2O and Cd3[FeIII(CN)6]2 · 15 H2O

1999 ◽  
Vol 54 (7) ◽  
pp. 870-876 ◽  
Author(s):  
Bernd Ziegler ◽  
Michael Witzel ◽  
Martin Schwarten ◽  
Dietrich Babel
Keyword(s):  
Crystal Structure ◽  
Ambient Temperature ◽  
Single Crystal ◽  
Single Crystals ◽  
Structure Refinement ◽  
Three Dimensional ◽  
Crystal Structure Refinement ◽  
X Ray Diffraction ◽  
One Dimensional ◽  
X Ray

The results of a Rietveld refinement of CsMnCr(CN)6 · D2O neutron powder data (a = 1084.3(1) pm, F4̄3m, Z = 4) and of a neutron single crystal structure refinement of tetragonal NMe4MnII(Cr0,06Mn0,94)III(CN)6 · 8 H2O (a = 1065.8(21), c = 1064.6(26) pm, P4/n, Z = 2) at ambient temperature are reported. Single crystal X-ray analyses of the isostructural octahydrate NMe4MnCo(CN)6 · 8 H20 (a = 1062.1 (1), c = 1046.2( 1) pm) and of gel-grown crystals of cubic Mn3II[MnIII(CN)6]2 - 15 H2O (a = 1062.6(3) pm, Fm3̄m, Z = 4/3) and Cd3[Fe(CN)6]2 · 15 H2O (a = 1067.7(3) pm) were performed as well. The latter “Prussian Blues” are highly disordered and intermediate with respect to cyano-bridging between the above three-dimensional cesium and one-dimensional tetramethylammonium compounds.

Iron in kornerupine; a57Fe Moessbauer spectroscopic study and comparison with single-crystal structure refinement

1999 ◽  
Vol 84 (4) ◽  
pp. 536-549 ◽  
Author(s):  
Edward S. Grew ◽  
Guenther J. Redhammer ◽  
Georg Amthauer ◽  
Mark A. Cooper ◽  
Frank C. Hawthorne ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Spectroscopic Study ◽  
Structure Refinement ◽  
Single Crystal Structure ◽  
Crystal Structure Refinement

Two lithium tricyanomethanide compounds: syntheses and single-crystal structure determination of LiK[C(CN)3]2 and Li[C(CN)3]·½ (H3C)2CO

2015 ◽  
Vol 70 (3) ◽  
pp. 191-196 ◽  
Author(s):  
Olaf Reckeweg ◽  
Francis J. DiSalvo
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Single Crystals ◽  
Structure Determination ◽  
Monoclinic Space Group ◽  
Orthorhombic Space Group ◽  
Space Group ◽  
Cell Parameters ◽  
New Compounds

AbstractThe new compounds LiK[C(CN)3]2 and Li[C(CN)3]·½ (H3C)2CO were synthesized and their crystal structures were determined. Li[C(CN)3]·½ (H3C)2CO crystallizes in the orthorhombic space group Ima2 (no. 46) with the cell parameters a=794.97(14), b=1165.1(2) and c=1485.4(3) pm, while LiK[C(CN)3]2 adopts the monoclinic space group P21/c (no. 14) with the cell parameters a=1265.7(2), b=1068.0(2) and c=778.36(12) pm and the angle β=95.775(7)°. Single crystals of K[C(CN)3] were also acquired, and the crystal structure was refined more precisely than before corroborating earlier results.

Calcium Carbodiimide Compounds Revisited – Syntheses, Single Crystal Structure Determination and Vibrational Spectra of Ca11N6[CN2]2, Ca4N2[CN2] and Ca[CN2]

2008 ◽  
Vol 63 (5) ◽  
pp. 530-536 ◽  
Author(s):  
Olaf Reckeweg ◽  
Francis J. DiSalvo
Keyword(s):  
Crystal Structure ◽  
Raman Spectrum ◽  
Single Crystal ◽  
Single Crystals ◽  
Vibrational Spectra ◽  
Structure Determination ◽  
X Ray ◽  
Characteristic Features ◽  
Reported Data ◽  
Correct Data

Single crystals of Ca11N6[CN2]2 (dark red needles, tetragonal, P42/mnm (no. 136), a = 1456.22(5), and c = 361.86(2) pm, Z = 2), Ca4N2[CN2] (transparent yellow needles, orthorhombic, Pnma (no. 62), a = 1146.51(11), b = 358.33(4), and c = 1385.77(13) pm, Z = 4) and Ca[CN2] (transparent, colorless, triangular plates, rhombohedral, R3̅m (no. 166), a = 369.00(3), and c = 1477.5(3) pm, Z = 3) were obtained by the reaction of Na2[CN2], CaCl2 and Ca3N2 (if demanded by stoichiometry) in arc-welded Ta ampoules at temperatures between 1200 - 1400 K. Their crystal structures were re-determined by means of single crystal X-ray structure analyses. Additionally, the Raman spectra were recorded on these same single crystals, whereas the IR spectra were obtained with the KBr pellet technique. The title compounds exhibit characteristic features for carbodiimide units with D∞h symmetry (d(C-N) = 121.7 - 123.8 pm and ∡ (N-C-N) = 180°). The vibrational frequencies of these units are in the expected range (Ca11N6[CN2]2: νs = 1230, νs = 2008; δ = 673/645/624 cm−1; Ca4N2[CN2]: νs = 1230, νs = 1986; δ = 672/647 cm−1; Ca[CN2]: νs = 1274, νs = 2031, δ = 668 cm−1). The structural results are more precise than the previously reported data, and with the newly attained Raman spectrum of Ca11N6[CN2]2 we correct data reported earlier.

Crystal and powder XRD data of Mg3(PO4)2-III: High-temperature and high-pressure form

1995 ◽  
Vol 10 (4) ◽  
pp. 293-295 ◽  
Author(s):  
F. Brunet ◽  
C. Chopin ◽  
A. Elfakir ◽  
M. Quarton
Keyword(s):  
Crystal Structure ◽  
High Pressure ◽  
High Temperature ◽  
Single Crystal ◽  
Diffraction Pattern ◽  
Structure Refinement ◽  
Powder Xrd ◽  
Single Crystal Structure ◽  
Crystal Structure Refinement ◽  
Pressure Form

A new diffraction pattern of the high-temperature and high-pressure polymorph Mg3(PO4)2-III (PDF 43-500) is given and indexed on the basis of a single-crystal structure refinement. It allows diffractogram indexing of the isostructural high-temperature and high-pressure form of Co3(PO4)2 (PDF 43-499).

Protoenstatite: a crystal-structure refinement at 1100°C

1971 ◽  
Vol 134 (3-4) ◽  
Author(s):  
Joseph R. Smyth
Keyword(s):  
Crystal Structure ◽  
Melting Point ◽  
Single Crystal ◽  
Structure Refinement ◽  
Three Dimensional ◽  
Intensity Data ◽  
Crystal Structure Refinement ◽  
Space Group

AbstractTechniques allowing single-crystal investigations on the precession camera up to the melting point of platinum have been developed. The crystal structure of protoenstatite has been refined from three-dimensional intensity data obtained at 1100°C using a crystal of enstatite from the Norton County, Kansas meteorite. The space group is

scholarly journals Redetermination of Sr2PdO3 from single-crystal X-ray data

2019 ◽  
Vol 75 (1) ◽  
pp. 30-32
Author(s):  
Gohil S. Thakur ◽  
Hans Reuter ◽  
Claudia Felser ◽  
Martin Jansen
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Diffraction Data ◽  
Structure Refinement ◽  
Structure Type ◽  
X Ray Diffraction ◽  
High Quality ◽  
X Ray ◽  
Cell Parameters ◽  
Anisotropic Displacement Parameters

The crystal structure redetermination of Sr2PdO3 (distrontium palladium trioxide) was carried out using high-quality single-crystal X-ray data. The Sr2PdO3 structure has been described previously in at least three reports [Wasel-Nielen & Hoppe (1970). Z. Anorg. Allg. Chem. 375, 209–213; Muller & Roy (1971). Adv. Chem. Ser. 98, 28–38; Nagata et al. (2002). J. Alloys Compd. 346, 50–56], all based on powder X-ray diffraction data. The current structure refinement of Sr2PdO3, as compared to previous powder data refinements, leads to more precise cell parameters and fractional coordinates, together with anisotropic displacement parameters for all sites. The compound is confirmed to have the orthorhombic Sr2CuO3 structure type (space group Immm) as reported previously. The structure consists of infinite chains of corner-sharing PdO4 plaquettes interspersed by SrII atoms. A brief comparison of Sr2PdO3 with the related K2NiF4 structure type is given.

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