Melting of rhombohedral boron subnitride B13N2 has been studied in situ at pressures to 8 GPa using synchrotron X-ray diffraction and electrical resistivity measurements. It has been found that above 2.6 GPa B13N2 melts incongruently, and the melting curve exhibits positive slope of 31(3) K/GPa that points to a lower density of the melt as compared to the solid phase.
@article{arxiv.1705.03753,
title = {On melting of boron subnitride B13N2 under pressure},
author = {Vladimir L. Solozhenko and Vladimir A. Mukhanov},
journal= {arXiv preprint arXiv:1705.03753},
year = {2017}
}