New Type of A₅B₃ Structure in Al–Ti and Ga–Ti Systems; Al₅Ti₃ and Ga₅Ti₃

Abstract

By electron diffraction and X-ray powder diffraction, a new type of A 5 B 3 -structure based on the L1 0 -type was found in the Al–Ti and Ga–Ti systems; Al 5 Ti 3 and Ga 5 Ti 3 . The structure has a tetragonal symmetry with the space group, P 4/ m b m , and the lattice constants, 2√2 a f and c f , where a f and c f are those of the fundamental L1 0 -type cell. 20 Al (or Ga) and 12 Ti atoms are contained in the unit cell. The structure can be described as follows: it consists of the domains based on the L1 2 , containing 3×2 columns of Ti atoms, and the domain boundaries have the L1 0 -type atomic arrangement.