Thermal expansion of cuprous oxide at low temperatures

The linear thermal expansion coefficient alpha of cuprite (Cu2O) has been measured from 2 to 30K, 55 to 90K, and at room temperature; alpha is negative at low temperatures with a minimum value of -3*10-6 K-1 near 80K. The Gruneisen parameter has a limiting value of gamma 0=-4.5+or-0.2 at liquid helium temperatures, in fair agreement with the value of -4.0 calculated from elastic data.