The thermal expansion of graphite: part II. Theoretical

A theory of the thermal expansion of hexagonal crystals is derived, and shown to account quantitatively for the experimental data on graphite. Certain of the elastic moduli for graphite are estimated, and are at 18°c. approximately: s11+s12= 1.8×10-13 cm./dyne s13=-4.3×10-13 cm./dyne s33= 58.5×10-13 cm./dyne Hence the two linear compressibilities are, at 18°c., approximately: kperpendicular=-2.5×10-13 cm2/dyne; kparallel=50×10-13 cm2./dyne.