  Two new methods to produce nanopowders of B12P2 boron subphosphide by
self-propagating high-temperature synthesis have been proposed. Bulk
polycrystalline B12P2 with microhardness of HV = 35(3) GPa and stability in air
up to 1300 K has been prepared by sintering these powders at 5.2 GPa and 2500
K.
