Crystal structure, electric field gradient, and electronic charge densities in ReB2: A single crystal x-ray, B11 nuclear magnetic resonance, and first-principles study

2009 ◽  
Vol 106 (3) ◽  
pp. 033514 ◽  
Author(s):  
O. J. Żogał ◽  
Z. Fojud ◽  
P. Herzig ◽  
A. Pietraszko ◽  
A. B. Lyashchenko ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Electric Field ◽  
Single Crystal ◽  
Electric Field Gradient ◽  
First Principles ◽  
Electronic Charge ◽  
X Ray ◽  
Charge Densities

The crystal structure of ethyl-Z-3-amino-2-benzoyl-2-butenoate and measurement of the barrier to E,Z-isomerization

1980 ◽  
Vol 58 (17) ◽  
pp. 1821-1828 ◽  
Author(s):  
Gary D. Fallon ◽  
Bryan M. Gatehouse ◽  
Allan Pring ◽  
Ian D. Rae ◽  
Josephine A. Weigold
Keyword(s):  
Crystal Structure ◽  
Nuclear Magnetic Resonance ◽  
Hydrogen Bond ◽  
Free Energy ◽  
Magnetic Resonance ◽  
Energy Of Activation ◽  
X Ray ◽  
X Ray Crystallography ◽  
Free Energy Of Activation ◽  
Nuclear Magnetic

Ethyl-3-amino-2-benzoyl-2-butenoate crystallizes from pentane as either the E (mp 82–84 °C) or the Z-isomer (mp 95.5–96.5 °C). The E isomer is less stable, and changes spontaneously into the Z, which bas been identified by X-ray crystallography. The structure is characterised by an N–H/ester CO hydrogen bond and a very long C2—C3 bond (1.39 Å). Nuclear magnetic resonance methods have been used to measure the rate of [Formula: see text] isomerization at several temperatures, leading to the estimate that the free energy of activation at 268 K is 56 ± 8 kJ.

scholarly journals Crystal Structures of Al2Cu Revisited: Understanding Existing Phases and Exploring Other Potential Phases

Metals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 1037 ◽  
Author(s):  
Sai Wang ◽  
Changzeng Fan
Keyword(s):  
Crystal Structure ◽  
High Pressure ◽  
Single Crystal ◽  
First Principles ◽  
First Principles Calculations ◽  
X Ray Diffraction ◽  
X Ray ◽  
Structural Relationships ◽  
Al2cu Phase ◽  
High Pressure Sintering

When processing single crystal X-ray diffraction datasets for twins of Al2Cu sample synthesized by the high-pressure sintering (HPS) method, we have clarified why the crystal structure of Al2Cu was incorrectly solved about a century ago. The structural relationships between all existing Al2Cu phases, including the Owen-, θ-, θ’-, and Ω-Al2Cu phases, were investigated and established based on a proposed pseudo Al2Cu phase. Two potential phases have been built up by adjusting the packing sequences of A/B layers of Al atoms that were inherent in all existing Al2Cu phases. The mechanical, thermal, and dynamical stability of two such novel phases and their electronic properties were investigated by first-principles calculations.

Sign in / Sign up

Export Citation Format

Share Document