Figure 5
Ordered occupation of metal atoms in M3B2-type boride.
(a)–(c) Atomic HAADF image taken along [001]M3B2, [100]M3B2 and [110]M3B2 direction, respectively, reveals the ordered occupation of metal atoms M in M3B2 phase. (d) Atomic configuration in the unit cell of M3B2 phase with ordered occupation of metal atoms. The blue balls represent large metal atoms (designated as L) such as W and Mo. The green balls represent relatively smaller metal atoms (designated as S) such as Cr, Co and Ni. The B atoms are indicated by red balls. The ordered M3B2 phase should be treated as a ternary boride with the chemical formula of L2SB2. (e)–(g) Structural projection of ordered M3B2 phase (L2SB2) along [001]M3B2, [100]M3B2 and [110]M3B2 direction, respectively. The main directions in each zone-axis are indicated with arrows. The atomic column marked by 1 and 1′ in (a)–(c) and (e)–(g) have the same atomic number density (AND) along the projected direction but with different atomic occupations. The upward arrows marked at column 1 and 2 in (c) and (g) indicate the same atomic occupation but with different ANDs along the projected direction.
