Recently we reported a novel qtz C 6 belonging to space group P6 5 22 (No. 179) with a single 6-fold Wyckoff position . To consider binary compounds, it was necessary to change the space group to P6 2 22 (No. 180), with a splitting into two 3-fold Wyckoff positions. The results of the unconstrained geometry optimizations are shown in Table . A comparison of zb-BX (X = As, Sb, Bi) shows a systematic decrease in volume as per formula unit (FU), which suggests densification.