Table 1. The lattice parameters and volume per atom in H-graphite and M-carbon, as well as the corresponding Birch-Murnaghan EOS parameters, assuming K0x' = 4. Uncertainties are given in parentheses. V0 represents the volume occupied by each atom. Note that for H-graphite, K0a ≫ K0c, indicative of the highly anisotropic nature of graphite. For M-carbon, the monoclinic angle β is measured and fluctuates with pressure (Fig. 2), thus we assume an average value of 97.38° (0.79°). The Birch-Murnaghan-like EOS fit for the lattice parameters is for data collected on compression, whereas all of the volume data is used to fit the complete Birch-Murnaghan EOS. Where values are not available or given, NA is noted.
| a0 (Å) | K0a (GPa) | b0 (Å) | K0b (GPa) | c0 (Å) | K0c (GPa) | β (deg) | V0a (Å3) | V0b (Å3) | K0b (GPa) | Ref | |
|---|---|---|---|---|---|---|---|---|---|---|---|
| H-graphite | 2.462 (0.001) | 442 (6) | 6.721 (0.002) | 12.0 (0.1) | 8.817 (0.011) | 57.3 (0.8) | Present work | ||||
| 2.461 (NA) | 516 (41) | 6.708 (NA) | 14.9 (0.5) | 8.797 (NA) | 67.4 (3.8) | 9 | |||||
| 2.459 (0.004) | 481 (32) | 6.706 (0.003) | 11.9 (0.1) | 8.78 (0.01) | 51.2 (1.4) | 10 | |||||
| M-carbon | 9.123 (0.001) | 527 (2) | 2.559 (0.001) | 271 (1) | 4.088 (0.001) | 267 (1) | 97.38 (0.79) | 5.91 (0.05) | 5.84 (0.05) | 365 (38) | Present work |
| 9.089 (NA) | NA | 2.496 (NA) | NA | 4.104 (NA) | NA | 96.96 (NA) | 5.78 (NA) | 431.2 (NA) | 25 |
aV0 as calculated by zero pressure lattice parameters determined by linear Birch-Murnaghan-like fit.
bV0 and K0 as determined by Birch-Murnaghan EOS fit.