Based on crystal chemistry and density functional theory calculations, superdense hexagonal (P6 4 22) boron pnictides BX (X = As, Sb, Bi) with quartz-derived topology were predicted as possible high-pressure phases. The new hexagonal qtz BX phases were found to be cohesive, with higher energies than the cubic zinc-blende (F-43m) polymorphs, but they tend to predominate at low volumes (high pressures). The transition pressures calculated from the corresponding energyvolume E(V) equations of state are 117 GPa (BAs), 71 GPa (BSb), and 51 GPa (BBi). In addition to mechanical stability from elastic constants, the qtz BX phases are also dynamically stable as indicated by the phonon band structures. The heat capacities of the qtz phases calculated from the phonon frequencies were found to be slightly higher than those of the corresponding zinc-blende phases which is quite expected for structures containing distorted corner-sharing tetrahedra. From the analysis of the electronic band structures, it was found that all zinc-blende boron pnictides have larger band gaps than the corresponding qtz phases, which can be attributed to an increased covalence due to the higher density of the latter. A special feature observed for metallic qtz BBi is related to the dynamic instability observed from the phonon band structure. * Experimental values: B 0 = 148(6) GPa and B B 0 0 ʹ ʹ = 3.9(3) ; B 0 = 148(9) GPa [45] † Experimental value: V 0 /FU = 27.26 Å 3