Investigations on structural determination of semi-transition-metal borides. Issue 47 (27th November 2017)

• Record Type: Journal Article
• Authors: Wang, Menglong; Liu, Chang; Wen, Mao; Li, Quan; Ma, Yanming
• Is Part Of: Physical chemistry chemical physics. Volume 19:Issue 47(2017)
• Page Start: 31592
• Page End: 31598
• Publication Date: 2017-11-27
• Subjects: Chemistry, Physical and theoretical -- Periodicals; 541.3
• DOI: 10.1039/c7cp06550g
• Languages: English
• ISSNs: 1463-9076

Abstract

Abstract : The present calculations show a series of semi-transition-metal borides with the long-assumed I 4/ mcm symmetry are dynamically unstable and I 4/ m structure is predicted to be both energetically and dynamically stable by freezing the unstable phonon mode. Abstract : Lack of systematic investigations on their dynamical and energetic stability preclude the full understanding of the structural determination and the corresponding mechanical properties for the semi-transition-metal borides ε2 B (ε = Ti, V, Cr, Mn, Fe, Co, Ni, Nb, Mo, Ta, and W). The present energetic calculations show ν2 B (ν = Ti, V, Cr, Nb, Mo, Ta and W) with the long-assumed I 4/ mcm symmetry are dynamically unstable, stemming from the large volume required to accommodate the boron atom at equilibrium. By freezing the unstable phonon mode, I 4/ m structure is predicted to be both energetically and dynamically stable. The structural stabilities for these compounds at finite temperature have been identified by the calculated Gibbs free energies and ab initio molecular dynamic simulation.