Binary and ternary compounds in the Mg-Sb-B and Mg-Bi-B systems as catalysts for the synthesis of cubic BN

We have studied the phase relations in the Mg-Pn and Mg-B-Pn (Pn = Sb, Bi) systems, synthesized the magnesium pnictides Mg₃Sb₂ and Mg₃Bi₂ and the new magnesium boropnictides Mg₃Pn₂(B₂), and determined their structure and unit-cell parameters. The synthesized compounds have been investigated at high pressures (4.0–6.5 GPa) and temperatures (700–1400°C). All of them have been found to promote the hexagonal-to-cubic phase transformation of boron nitride.