Bonding and hardness of LnMgAl11O19(Ln = La; Pr; Nd; Sm; Eu; Gd)

The chemical bond parameters of LnMgAl11O19 (Ln = La, Pr, Nd, Sm, Eu, Gd) were calculated using the chemical bond dielectric theory of complex structural crystals. The hardness of LnMgAl11O19 was predicted. The results indicated that the origin of the high hardness of LnMgAl11O19 results mainly from AlO units.