S. Zamir et al., A SINGLE-CRYSTAL TO SINGLE-CRYSTAL REVERSIBLE PHASE-TRANSITION WHICH EXHIBITS THE HOPPING EFFECT, Molecular crystals and liquid crystals science and technology. Section A, Molecular crystals and liquid crystals, 242, 1994, pp. 193-200
A reversible phase transition involving jumping of the crystal in the
process of heating and cooling is described. If crystals are fixed to
the heating area, physical expansion and contraction are observed when
heated and cooled respectively. From the crystal structure of Form I
and the powder diffraction of Form II it was found that the expansion
and contraction occurs in the direction of the b axis.