Crystal structure and hydrogenation ...
Document type :
Article dans une revue scientifique
Permalink :
Title :
Crystal structure and hydrogenation properties of Pd5As
Author(s) :
Kohlmann, Holger [Auteur]
Vasseur, M. [Auteur]
Sayede, Adlane [Auteur]
Unité de Catalyse et Chimie du Solide - UMR 8181 [UCCS]
Lefevre, Gauthier [Auteur]
Unité de Catalyse et Chimie du Solide - UMR 8181 [UCCS]
Sander, J.M. [Auteur]
Doyle, S. [Auteur]
Vasseur, M. [Auteur]
Sayede, Adlane [Auteur]

Unité de Catalyse et Chimie du Solide - UMR 8181 [UCCS]
Lefevre, Gauthier [Auteur]

Unité de Catalyse et Chimie du Solide - UMR 8181 [UCCS]
Sander, J.M. [Auteur]
Doyle, S. [Auteur]
Journal title :
Journal of Alloys and Compounds
Volume number :
664
Pages :
256-265
Publication date :
2016-04-15
HAL domain(s) :
Chimie/Chimie inorganique
English abstract : [en]
The crystal structure of Pd5As was refined simultaneously from laboratory X-ray, synchrotron and neutron powder diffraction data (space group C2/m, a = 551.82(2) pm, b = 774.50(3) pm, c = 842.13(4), β = 99.037(2)°, Z = 4). ...
Show more >The crystal structure of Pd5As was refined simultaneously from laboratory X-ray, synchrotron and neutron powder diffraction data (space group C2/m, a = 551.82(2) pm, b = 774.50(3) pm, c = 842.13(4), β = 99.037(2)°, Z = 4). This is in contrast to earlier work, which describes the structure in the non-centrosymmetric space group C2. Eight palladium atoms form a bicapped trigonal prism around arsenic. Two such polyhedra are connected by a common edge to double prisms (average distance As–Pd 252 pm). Palladium has got coordination numbers of 11 (average distance 276 pm) or 12 (average distance of 278 pm). The crystal structure of Pd5As represents a strongly distorted cubic closest packing as proven by crystallographic group–subgroup relationships. Pd5As does not take up hydrogen up to 5.0 MPa hydrogen pressure and temperatures up to 723 K. Quantum-mechanical calculations using DFT methods using an ab initio evolutionary algorithm confirm the crystal structure of Pd5As and reveal the stability of a hypothetical hydride Pd5AsH. The lack of reactivity might be due to kinetic hindrance because of an endothermic rearrangement of the metal matrix necessary for hydrogen incorporation. Above 5.8 GPa, however, this phase transition becomes thermodynamically favourable, making hydrogenation of Pd5As likely to occur.Show less >
Show more >The crystal structure of Pd5As was refined simultaneously from laboratory X-ray, synchrotron and neutron powder diffraction data (space group C2/m, a = 551.82(2) pm, b = 774.50(3) pm, c = 842.13(4), β = 99.037(2)°, Z = 4). This is in contrast to earlier work, which describes the structure in the non-centrosymmetric space group C2. Eight palladium atoms form a bicapped trigonal prism around arsenic. Two such polyhedra are connected by a common edge to double prisms (average distance As–Pd 252 pm). Palladium has got coordination numbers of 11 (average distance 276 pm) or 12 (average distance of 278 pm). The crystal structure of Pd5As represents a strongly distorted cubic closest packing as proven by crystallographic group–subgroup relationships. Pd5As does not take up hydrogen up to 5.0 MPa hydrogen pressure and temperatures up to 723 K. Quantum-mechanical calculations using DFT methods using an ab initio evolutionary algorithm confirm the crystal structure of Pd5As and reveal the stability of a hypothetical hydride Pd5AsH. The lack of reactivity might be due to kinetic hindrance because of an endothermic rearrangement of the metal matrix necessary for hydrogen incorporation. Above 5.8 GPa, however, this phase transition becomes thermodynamically favourable, making hydrogenation of Pd5As likely to occur.Show less >
Language :
Anglais
Audience :
Internationale
Popular science :
Non
Administrative institution(s) :
ENSCL
CNRS
Centrale Lille
Univ. Artois
Université de Lille
CNRS
Centrale Lille
Univ. Artois
Université de Lille
Collections :
Research team(s) :
Couches minces & nanomatériaux (CMNM)
Submission date :
2019-09-25T14:05:21Z
2021-05-18T12:55:37Z
2021-05-18T12:55:37Z