Thermodynamics of iodine under high pressure at low temperatures

It is shown that the Clapeyron equation fails to describe the phase diagram of iodine at low temperatures. Instead, a modified Clapeyron equation is offered, which gives much better results. It is supposed that the transition from the low-pressure phase to the high-pressure phase happens like this: molecular phase-molecular phase with a body-centred orthorombic Bravais lattice-monatomic phase with a body-centred orthorombic Bravais lattice. (C) 2004 Elsevier B.V. All rights reserved.