Structural Phase Transition of Orthorhombic LaCrO3 Studied by Neutron Powder Diffraction

2000 ◽  
Vol 154 (2) ◽  
pp. 524-529 ◽  
Author(s):  
K. Oikawa ◽  
T. Kamiyama ◽  
T. Hashimoto ◽  
Y. Shimojyo ◽  
Y. Morii
Keyword(s):  
Phase Transition ◽  
Structural Phase Transition ◽  
Powder Diffraction ◽  
Structural Phase ◽  
Neutron Powder Diffraction

High Resolution Neutron Powder Diffraction Studies of the Ferroelastic Phase Transition in LaNbO4

1989 ◽  
Vol 166 ◽  
Author(s):  
W I F David
Keyword(s):  
Phase Transition ◽  
High Resolution ◽  
Powder Diffraction ◽  
Structural Phase ◽  
Strain Tensor ◽  
Neutron Powder Diffraction ◽  
Line Broadening ◽  
Neutron Powder Diffraction Data ◽  
Ferroelastic Phase Transition ◽  
Principal Axes

ABSTRACTAnalysis of high resolution neutron powder diffraction data of ferroelastic LaNbO4 indicates a monoclinic to tetragonal structural phase transition that is accompanied by anomalous line broadening. The origins of this line broadening have been investigated using a novel modification of the Rietveld technique. The results show that strain broadening is associated with the ferroelastic phase transition both above and below the transition temperature. This anomalous ‘microstrain’ is well-described by a second rank strain tensor, the principal axes of which are collinear with the spontaneous lattice strain. This phenomenon may be a general feature of proper ferroelastic phase transitions.

Structural phase transition in GaMo4Se8 and AlMo4S8 by X-ray powder diffraction

1992 ◽  
Vol 200 (1-4) ◽  
Author(s):  
Μ. François ◽  
Ο. V. Alexandroν ◽  
K. Yvon ◽  
H. Ben Yaich-Aerrache ◽  
P. Gougeon ◽  
...  
Keyword(s):  
Phase Transition ◽  
Structural Phase Transition ◽  
Powder Diffraction ◽  
Structural Phase ◽  
X Ray

The Crystal Structure of [Mg2(H2O)6(HCO3)3]+Cl–, Containing a Magnesium-based Hetero-polycation

2008 ◽  
Vol 63 (12) ◽  
pp. 1347-1351 ◽  
Author(s):  
Robert E. Dinnebier ◽  
Martin Jansen
Keyword(s):  
Crystal Structure ◽  
Phase Transition ◽  
High Resolution ◽  
Structural Phase Transition ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
Structural Phase ◽  
Close Packing ◽  
Powder Diffraction Data ◽  
Hydrogen Carbonate

The crystal structure of di-magnesium hexahydrate trihydrogencarbonate chloride, [Mg2(H2O)6- (HCO3)3]+Cl−, has been determined from high-resolution laboratory powder diffraction data (lattice parameters at r. t.: a = 8.22215(2), c = 39.5044(2) Å, V = 2312.85(2) Å3, space group R3̄̄c, Z = 6). The crystal structure of [Mg2(H2O)6(HCO3)3]+Cl− is built up of alternating sheets of Cl− anions and complex [Mg2(H2O)6(HCO3)3]+ cations consisting of two Mg(OH2)3O3 octahedra interconnected by three disordered hydrogen carbonate groups. The packing can be described as a cubic close packing of [Mg2(H2O)6(HCO3)3]+ cations with the Cl− anions filling all octahedral voids. In the temperature range from r. t. up to decomposition, which takes place in the range 398 K < T < 413 K, no structural phase transition occurs.

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