The refined relative volume (V 0 /V ) is plotted as a function of calculated pressure for each solid solution in Figure , while a third-order Birch-Murnaghan EOS (Equation ) is fit to each dataset to determine V 0 , K 0 , and K 0 . 24 Table presents the experimentally determined V 0 , K 0 , and K 0 for each of the three solid solutions, as well as values for a Mo 0.9 W 1.1 BC composition from a previous work and DFT and ab initio calculated values for MoWBC and Mo 2 BC from other sources. Table : Experimentally determined V 0 , K 0 , and K 0 for Mo 2-x W x BC solid solutions, including results reported in a previous work. DFT and ab initio calculated values for Mo 2 BC and MoWBC are also presented for reference. 3 rd -order B-M EOS DFT ab initio 18 For the experimentally evaluated Mo 2-x W x BC solid solutions, K 0 appears to directly correlate with increasing W content and decreasing Mo content, from K 0 = 333(9) GPa for Mo 2 BC to K 0 = 373(4) GPa for Mo 0.9 W 1.1 BC. These findings indicate that bulk compressibility of the Mo 2-x W x BC structures, particularly the tungsten-rich compositions, are comparable to values reported for WB 4 (K 0 = 369(9) GPa and K 0 = 1.2(5)). Additionally, calculated V 0 of Mo 2-x W x BC generally decreases as W content increases, in agreement with X-ray diffraction results reported previously, and can be explained by shorter, stronger bonding among the TM s. Reduced crystal volume also correlates to increased valence electron In addition to the exceptional bulk moduli, hardness, and ductility of this system, understanding these properties in the context of the anisotropic lattice strain and texture development when exposed to nonhydrostatic stresses can inform future efforts to implement Mo 2-x W x BC solid solutions in applications requiring wear-resistance. Previously, nonhydrostatic compression experiments on Mo 0.9 W 1.1 BC investigated anisotropic deformation behavior and found that the (002) and (200) planes parallel to the long b-axis support the greatest differential strain. These planes are orthogonal to the covalently bonded boron chains, which likely provide additional elastic support and decrease the susceptibility to slip. Furthermore, lattice preferred orientation was demonstrated along planes parallel to the covalent chains, suggesting that dislocation glide occurs in directions that do not require the breaking of B-B bonds. Mansouri Tehrani et al. used stress-strain calculations to investigate the anisotropic, nonlinear elastic behavior of Mo 2 BC and observed tensile strain stiffening along the [001] direction. The observed stiffening was attributed to the formation of an electronic pseudogap within the density of state and the dimerization of the boron-boron chains, delaying shear failure and enhancing ultimate strength and strain. Additionally, the (111) [ 11 2] was identified as the softest shear plane, contributing to the ductility of the structure. Because the Mo 2-x W x BC solid solutions are isostructural, it is anticipated that the deformation mechanisms are similar across this system.