300-K equation of state of rhombohedral boron subnitride, B13N2

Quasi-hydrostatic compression of rhombohedral boron subnitride has been studied up to 30 GPa at room temperature using angle-dispersive X-ray diffraction with synchrotron radiation. The alpha-rhombohedral boron type R (3) over barm structure Of B13N2 is stable in the whole pressure range under study. A fit of the experimental p-V data to the Birch equation of state yields the values of the bulk modulus, B-0, of 200(15) GPa with fixed first pressure derivative of the bulk modulus, B'(0), of 4.0. The compression is found to be slightly anisotropic with higher compressibility along c-axis. (C) 2009 Elsevier Ltd. All rights reserved.