Thermal Expansion of Y2SiO5 Single Crystals

The thermal expansion of Y₂SiO₅ crystals has been measured for the principal crystallographic directions and two orthogonal directions in the (010) plane in the temperature range 25° to 200°C. This monoclinic crystal has strongly anisotropic expansions with coefficients which range from 0.6 × 10⁻⁶/°C for 100] to 11.4 × 10⁻⁶/°C for 001]. Third-order polynomials have been calculated from the expansion curves. Data for the β angle and cell volume as a function of temperature are also given. The thermal expansion of Y₂SiO₅ crystals is not affected by doping with 5% Tb.