Properties of major SiC polytypes[4][23] Polytype 3C (β) 4H 6H (α) Crystal structure Zinc blende (cubic) Hexagonal Hexagonal Space group T2d-F43m C46v-P63mc C46v-P63mc Pearson symbol cF8 hP8 hP12 Lattice constants (Å) 4.3596 3.0730; 10.053 3.0810; 15.12 Density (g/cm3) 3.21 3.21 3.21 Bandgap (eV) 2.36 3.23 3.05 Bulk modulus (GPa) 250 220 220 Thermal conductivity (W m−1K−1) @ 300K (see [30] for temp. dependence) 360 370 490