Measurements were made of the transit times of pulses of longitudinal and transverse ultrasonic waves propagating in single crystals at room temperature. A unique set of values for the three independent elastic constants was obtained from the resultant velocities and was; C11 = (45.33 ± 0.11) x 1011, C12 = (1.82 ± 0.17) x 1011 and C44 = (9.01 ± 0.05) x 1011dyne/cm2. The Debye temperature deduced from these measurements was 773K, which agreed relatively well with the X-ray Debye temperature, but differed greatly from the calorimetric and electrical resistance Debye temperatures.

Elastic Constants of LaB6 at Room Temperature. Tanaka, T., Yoshimoto, J., Ishii, M., Bannai, E., Kawai, S.: Solid State Communications, 1977, 22[3], 203-5