Compressibility of hexagonal selenium to 45 kbar

Compression data to 45 kbar have been obtained for hexagonal selenium by static methods in a piston-cylinder apparatus. Cylindrical samples (1 cm dia. and 1·2 cm length) of polycrystalline hexagonal selenium, with a bulk density close to the X-ray density, were prepared by pressing the samples at 7 kbar and 170°C. The compression data are described by a third degree polynomial,

$?\left(\frac{\Delta V}{V_O}\right)=?64·14\times {10}^{?4}P+109·9\times {10}^{?6}{P}^2?96·77\times {10}^{?8}{P}^3$

,where P is pressure in kbar. The zero pressure bulk modulus and the pressure derivative of the bulk modulus are 156 ± 10 kbar and 4·33 respectively.