Io. Bashkin et al., REVERSIBLE 1ST-ORDER PHASE-TRANSITION WITH A LARGE CHANGE IN VOLUME IN THE FULLERITE C-60 UNDER PRESSURE, JETP letters, 59(4), 1994, pp. 279-282
An abrupt change in the pressure dependence of the volume of C60 at a
temperature of 557 K has been observed. This abrupt change is explaine
d in terms of a reversible first-order phase transition.