Resolving the structure of TiBe₁₂

Abstract

There has been considerable controversy regarding the structure of TiBe12, which is variously reported as hexagonal and tetragonal. Lattice dynamics simulations based on density functional theory (DFT) show the tetragonal phase space group I4/mmm to be more stable over all temperatures, while the hexagonal phase exhibits an imaginary phonon mode, which, if followed, would lead to the cell adopting the tetragonal structure. We then report the predicted ground state elastic constants and temperature dependence of the bulk modulus and thermal expansion for the tetragonal phase.

Study of Vacancy Clusters and Antisite Defects in Titanium Beryllide Be12Ti Using Positron Annihilation Spectroscopy

“…As shown in Figure 2a, although Be atoms occupy two different positions at the z = 0 and z = 0.5 planes, some are located at the same sites, in accordance with the symmetrical structure of the Be 12 Ti crystal. [23] Sites located in the z = 0 plane are referred to as Be2 while those in the z = 0.5 plane are referred to as Be3. 1), respectively.…”

“…Recent studies have demonstrated that Be 12 Ti forms a tetragonal lattice structure with I4/mmm symmetry. [23]…”

Aggregation of retained helium and hydrogen in titanium beryllide Be12Ti: a first-principles study

“…The bulk Be 12 Ti has tetragonal symmetry in the space group of I 4 /mmm. 38,39 Ti atoms occupy the Wyckoff position of the 2a lattice site (0, 0, 0), and three symmetrically different Be atoms, which are labeled as Be1, Be2 and Be3, occupy the Wyckoff positions of 8f (0.25, 0.25, 0.25), 8i (0.361, 0, 0) and 8j (0.277, 0.5, 0), respectively. The structure of the unit cell for Be 12 Ti is shown in Fig.…”

Valence Electron and Chemical State Analysis of Be12M (M = Ti, V) Beryllides by Soft X-ray Emission Spectroscopy

“…Burr et al reported that the Be–Fe­(-Al) intermetallics have much lower oxygen affinity than metallic Be by calculating solution energies of oxygen . The electronic structure and properties of Be 12 Ti were investigated by DFT calculations. , However, the studies on the electric structure were performed with disordered hexagonal cell with P 4 / mmm symmetry, which is pointed out to be incorrect and unstable. , To the best of our knowledge, no experimental investigation has reported on the electron structure of Be 12 M beryllide (M = Ti, V) until today.…”

“…19,20 However, the studies on the electric structure were performed with disordered hexagonal cell with P 4 /mmm symmetry, 21 which is pointed out to be incorrect and unstable. 13,22 To the best of our knowledge, no experimental investigation has reported on the electron structure of Be 12 M beryllide (M = Ti, V) until today. This study aims to (i) clarify the valence electron structure of Be 12 M (M = Ti, V) and (ii) perform compositional microanalysis of oxidized beryllide based on the information on electron structure.…”