scholarly journals Crystal structure and anti-site boundary defect characterisation of Cu2ZnSnSe4

2018 ◽  
Vol 6 (1) ◽  
pp. 189-197 ◽  
Author(s):  
B. G. Mendis ◽  
K. P. McKenna ◽  
G. Gurieva ◽  
M. S. Rumsey ◽  
S. Schorr
Keyword(s):  
Crystal Structure ◽  
Disorder Transition ◽  
Boundary Defect ◽  
Defect Characterisation

The crystal structure and anti-site boundaries in Cu2ZnSnSe4 are analysed at the nanometre scale on either side of the order–disorder transition.

scholarly journals Effect of the Order-Disorder Transition on the Seebeck Coefficient of Nanostructured Thermoelectric Cu2ZnSnS4

Nanomaterials ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 762 ◽  
Author(s):  
Eleonora Isotta ◽  
Carlo Fanciulli ◽  
Nicola M. Pugno ◽  
Paolo Scardi
Keyword(s):  
Crystal Structure ◽  
Solar Cell ◽  
Seebeck Coefficient ◽  
Ball Milling ◽  
Thermal Analyses ◽  
Expected Value ◽  
Crystal Symmetry ◽  
Disorder Transition ◽  
Cation Disorder ◽  
Second Order Transition

Bulk samples of kesterite (Cu2ZnSnS4, CZTS) were produced by cold-pressing and sintering of CZTS powders obtained via reactive ball-milling. An increase in the Seebeck coefficient of more than 100 μV/K, almost doubling the expected value, is noticed around a temperature of 260 °C. As pointed out by thermal analyses, this is due to a second order transition of kesterite from an ordered I-4 to a disordered I-42m crystal structure. Conversely to what happens for solar cell materials, where the transition is considered to be detrimental for the performance, it appears to be beneficial for the thermoelectric Seebeck coefficient, suggesting that higher crystal symmetry and cation-disorder due to the transition lead to thermopower enhancement.

Kristallstruktur und thermische Phasenumwandlung von Tetramethylammoniumcyanid, (CH3)4N+CN- / Crystal Structure and Thermal Phase Transition of Tetramethylammonium Cyanide, (CH3)4N+CN-

1999 ◽  
Vol 54 (3) ◽  
pp. 372-376 ◽  
Author(s):  
Andreas Komath ◽  
Oliver Blecher
Keyword(s):  
Crystal Structure ◽  
Phase Transition ◽  
Room Temperature ◽  
Temperature Phase ◽  
Cyanide Ion ◽  
Space Group ◽  
Disorder Transition ◽  
Thermal Phase Transition ◽  
Cell Dimensions ◽  
Thermal Phase

Tetramethylammonium cyanide crystallizes in the tetragonal space group P4/nmm, Z = 2, with cell dimensions a = 773.6(1), c = 546.8(1) pm. The cyanide ion is disordered in the plane perpendicular to the c-axis indicating a rotation. The room temperature phase undergoes a thermal phase transition at -59.9°C probably caused by an order-disorder transition of the cyanide ion.

The crystal and molecular structures of adamantanecarboxylic acid at 173 and 280 K

1990 ◽  
Vol 68 (7) ◽  
pp. 1163-1169 ◽  
Author(s):  
Francine Bélanger-Gariépy ◽  
François Brisse ◽  
Pierre D. Harvey ◽  
Denis F. R. Gilson ◽  
Ian S. Butler
Keyword(s):  
Crystal Structure ◽  
Direct Methods ◽  
High Temperature Phase ◽  
Molecular Structures ◽  
Temperature Phase ◽  
Carboxylic Group ◽  
Disorder Transition ◽  
Text Type ◽  
Adamantanecarboxylic Acid ◽  
Unit Cells

The crystal structure of adamantanecarboxylic acid, tricyclo[3.3.1.13,7] decan-1-carboxylic acid C10H15COOH, has been determined by X-ray diffraction at two temperatures, 173 and 280 K. At both temperatures, the unit cells are triclinic, space group[Formula: see text], and each contains two molecules. At 173 K, a = 6.452(3), b = 6.681(2), c = 11.510(3) Å, α = 80.84(2)°, β = 87.22(3)°, γ = 74.11(3)°; V = 471.10 Å3, Dx = 1.271 g cm−3, [Formula: see text]. The structure was solved by direct-methods. The least-squares refinement, based on 1347 observed reflections converged to R = 0.0485 and Rw = 0.0415. At 280 K, a = 6.503(2), b = 6.849(2), c = 11.620(4) Å, α = 77.11(2)°, β = 85.77(2)°, γ = 76.34(2)°; V = 490.11 Å3, Dx = 1.221 g cm−3, [Formula: see text], R = 0.0874, and Rw = 0.0512 for 828 observed reflections. The low-temperature form is ordered while at room temperature the molecule is disordered. In the structure of the high-temperature phase, the adamantyl group takes two distinct orientations, in a 60:40 proportion, at about 14° from one another. The carboxylic group also has two orientations differing by about 170°. The geometry of the adamantane skeleton is not affected by the presence of the carboxylic group. The molecules form centrosymmetric dimers through hydrogen bonds of the [Formula: see text] type. The [Formula: see text] distances range between 2.616(11) and 2.752(15) Å. The order-disorder transition is interpreted using the Guthrie–McCullough approach. Keywords: adamantanecarboxylic acid, order–disorder transition, crystal structure.

Crystallographic and molecular mechanics investigation of an order–disorder transition and dimorphism in 5H,10H-dithiolo[2,3-b]-2,5-benzodithiocine-2-thione

2000 ◽  
Vol 56 (6) ◽  
pp. 1011-1017 ◽  
Author(s):  
Zahid H. Chohan ◽  
William T. A. Harrison ◽  
R. Alan Howie ◽  
Bruce F. Milne ◽  
James L. Wardell
Keyword(s):  
Crystal Structure ◽  
Saddle Point ◽  
Molecular Mechanics ◽  
Title Compound ◽  
The Other ◽  
Molecular Mechanics Calculations ◽  
Disorder Transition ◽  
X Ray ◽  
Β Phase ◽  
Α Phase

Single-crystal X-ray structures are presented for three forms of 5H,10H-dithiolo[2,3-b]-2,5-benzodithiocine-2-thione. The α (at 150 K) and α′ (at ambient) forms are very similar and differ only in the presence of crystallographic m symmetry in the molecules of α′, which is absent in the case of α. This pair is related by an order–disorder transition. The β phase (also determined at 150 K) has a different structure in terms of the molecular packing from either of the other two and therefore constitutes a true polymorph. Molecular mechanics calculations indicated that the most stable CHCl3-solvated conformations for the title compound were a pair of twisted U-shaped enantiomers, UR and UL , i.e. similar to the arrangements found in the α and β phases, with the low-lying saddle point between them corresponding to the situation in the α′ phase. These calculations also indicated that the most stable CHCl3-solvated conformation for the related dibromo-5H,10H-dithiolo[2,3-b]-2,5-benzodithiocine-2-thione was Z-shaped, in agreement with the crystal structure determined earlier for its DMSO solvate [Wang et al. (1998). Synthesis, pp. 1615–1618].

Enantiotropic phase transition in a binuclear tin complex with anO,N,O′-tridentate ligand

2013 ◽  
Vol 69 (11) ◽  
pp. 1336-1339 ◽  
Author(s):  
Anke Schwarzer ◽  
Lydia E. H. Paul ◽  
Uwe Böhme
Keyword(s):  
Crystal Structure ◽  
Phase Transition ◽  
Cell Volume ◽  
Unit Cell Volume ◽  
Unit Cell ◽  
Tridentate Ligand ◽  
Asymmetric Unit ◽  
Disorder Transition ◽  
Vinyl Group

The crystal structure of chlorido{μ-2-[(2-oxidobenzylidene)amino]ethanolato-κ4O,N,O′:O′}{2-[(2-oxidobenzylidene)amino]ethanolato-κ3O,N,O′}trivinylditin(IV), [Sn2(C2H3)3(C9H9NO2)2Cl], is disordered above 178 K. A doubling of the unit-cell volume is observed on cooling. The asymmetric unit at 93 K contains two ordered molecules. The phase transition corresponds to an order–disorder transition of one vinyl group bound to the SnIVatom.

On the crystal structure of Cr2N precipitates in high-nitrogen austenitic stainless steel. II. Order–disorder transition of Cr2N during electron irradiation

2006 ◽  
Vol 62 (2) ◽  
pp. 190-196 ◽  
Author(s):  
Tae-Ho Lee ◽  
Sung-Joon Kim ◽  
Setsuo Takaki
Keyword(s):  
Crystal Structure ◽  
Electron Irradiation ◽  
Random Distribution ◽  
Regular Sequence ◽  
Disorder Transition ◽  
Disorder Phase Transition ◽  
Hexagonal Close Packed ◽  
Metal Atoms ◽  
Transmission Electron ◽  
Convergent Beam

The crystal structure and order–disorder transition of Cr2N were investigated utilizing transmission electron microscopy (TEM). Based on the analyses of selected-area diffraction (SAD) patterns, the crystal structure of the ordered Cr2N superstructure was confirmed to be trigonal (P\overline 3 1m), characterized by three sets of superlattice reflections (001), (1\over 31\over 30) and (1\over 31\over 31). During electron irradiation, the superlattice reflections gradually disappeared in the regular sequence (001), (1\over 31\over 30) and (1\over 31\over 31), indicating that the order–disorder phase transition of Cr2N occurred. The convergent-beam electron diffraction (CBED) observation revealed that the space group of disordered Cr2N is P63/mmc, which corresponds to an h.c.p. (hexagonal close packed) sublattice of metal atoms with a random distribution of N atoms in six octahedral interstices. The redistribution model of N atoms through the order–disorder transition is discussed based on the characteristics and disappearing sequence of superlattice reflections.

Crystal Structure Determination of Glycerol-Containing Lipids from Electron Diffraction Data. Use of Analog Compounds Based upon Configurational Isomers of Cyclopentane-1, 2, 3-TRIOL

1977 ◽  
Vol 35 ◽  
pp. 24-25
Author(s):  
Douglas L. Dorset ◽  
Anthony J. Hancock
Keyword(s):  
Crystal Structure ◽  
Electron Diffraction ◽  
Diffraction Data ◽  
Structure Determination ◽  
Crystal Surface ◽  
Coherent Scattering ◽  
Crystal Structure Determination ◽  
Electron Diffraction Data ◽  
Polar Group ◽  
Axis Orientation

Lipids containing long polymethylene chains were among the first compounds subjected to electron diffraction structure analysis. It was only recently realized, however, that various distortions of thin lipid microcrystal plates, e.g. bends, polar group and methyl end plane disorders, etc. (1-3), restrict coherent scattering to the methylene subcell alone, particularly if undistorted molecular layers have well-defined end planes. Thus, ab initio crystal structure determination on a given single uncharacterized natural lipid using electron diffraction data can only hope to identify the subcell packing and the chain axis orientation with respect to the crystal surface. In lipids based on glycerol, for example, conformations of long chains and polar groups about the C-C bonds of this moiety still would remain unknown.One possible means of surmounting this difficulty is to investigate structural analogs of the material of interest in conjunction with the natural compound itself. Suitable analogs to the glycerol lipids are compounds based on the three configurational isomers of cyclopentane-1,2,3-triol shown in Fig. 1, in which three rotameric forms of the natural glycerol derivatives are fixed by the ring structure (4-7).

Spherulitic crystal growth in the prodissoconch larval of Crassostrea virginica

1983 ◽  
Vol 41 ◽  
pp. 518-519
Author(s):  
George G. Cocks ◽  
Louis Leibovitz ◽  
DoSuk D. Lee
Keyword(s):  
Crystal Structure ◽  
Crassostrea Virginica ◽  
Crystal Orientation ◽  
Developmental Changes ◽  
Gastrula Stage ◽  
Orthorhombic Crystal ◽  
Orthorhombic Crystal Structure ◽  
Stages Of Growth ◽  
Early Stages ◽  
Initial Deposition

Our understanding of the structure and the formation of inorganic minerals in the bivalve shells has been considerably advanced by the use of electron microscope. However, very little is known about the ultrastructure of valves in the larval stage of the oysters. The present study examines the developmental changes which occur between the time of conception to the early stages of Dissoconch in the Crassostrea virginica(Gmelin), focusing on the initial deposition of inorganic crystals by the oysters.The spawning was induced by elevating the temperature of the seawater where the adult oysters were conditioned. The eggs and sperm were collected separately, then immediately mixed for the fertilizations to occur. Fertilized animals were kept in the incubator where various stages of development were stopped and observed. The detailed analysis of the early stages of growth showed that CaCO3 crystals(aragonite), with orthorhombic crystal structure, are deposited as early as gastrula stage(Figuresla-b). The next stage in development, the prodissoconch, revealed that the crystal orientation is in the form of spherulites.

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