Structure and equation of state of tetragonal boron subnitride B50N2

Abstract

New boron subnitride B50N2 has been synthesized by crystallization from the B-BN melt at 5 GPa, and its structure has been refined using Rietveld analysis. B50N2 crystallizes in the tetragonal space group P-4n2 with unit cell parameters a = 8.8181(2) A and c = 5.0427(10) A. Quasi-hydrostatic compression of two boron subnitrides, B50N2 and B13N2, has been studied to 30 GPa at room temperature in a diamond-anvil cell using synchrotron X-ray diffraction. No pressure-induced phase transitions have been observed. A fit of experimental p-V data to the Murnaghan equation of state yielded B50N2 and B13N2 bulk moduli of 167(2) and 205(2) GPa, respectively, with fixed first bulk modulus pressure derivative of 4.0

Equations of state of new boron-rich selenides B6Se and B12Se

“…5). Our results support the general trendincrease of covalent radius of interstitial atom in the row of boron-rich chalcogenides (α-B12 [23] -B12O2 [24] -B12Se) leads to decrease of bulk moduluswhich has been already observed in the row of boron-rich pnictides (α-B12 [23] -B13N2 [25] -B12P2 [26] -B12As2 [20]). However, as it follows from Fig.…”

Thermal expansion of α-boron and some boron-rich pnictides

“…Interestingly, the volume TECs and bulk moduli (B0) of B13N2, B12P2 and B12As2 [29][30][31] vary similar (see Table I and Fig. 3b).…”

“…The obtained values were compared with the literature data for boron subnitride B13N2, and variation of αl and αv of three boronrich pnictides was analyzed in terms of their crystal structure. expansion coefficients of α-B12, B13N2, B12P2, B12As2 versus bulk modulus (B0) [29][30][31][32]; the dashed line represents exponential fit.…”

Chemical vapour deposition of sp2-hybridised B-C-N materials from organoborons

“…As most boron compounds, boron nitrides can be divided into two groups: stochiometric BN (or boron mononitride), which is isoelectronic and structurally similar to carbon, and rhombohedral boron subnitride, which presents similarities with rhombohedral boron carbide. Other reported controversial subnitrides such as tetragonal B50N2 48 will not be discussed in this section.…”