Experimental study and critical review of structural, thermodynamic and   mechanical properties of superhard refractory boron suboxide, B6O
  In the present paper we performed the analysis of available data on structural, thermodynamic and mechanical properties of B6O. Although the compound is known for half a century and has been extensively studied, many properties of this boron-rich solid remain unknown or doubtful. Semi-empirical analysis of our experimental and literature data allowed us to choose the best values of main thermodynamic and mechanical characteristics among previously reported data, to predict the thermoelastic equation of state of B6O, and dependence of its hardness on non-stoichiometry and temperature. 
Oleksandr O. Kurakevych, Vladimir L. Solozhenko
cond-mat.mtrl-sci physics.chem-ph