Solid-state studies on a cubic 1 : 1 solvate of C-60 grown from dichloromethane and leading to another hexagonal C-60 polymorph

Crystals of a C-60 1:1 solvate (I-centered cubic, a = 23.284(2) Angstrom) w ere grown by evaporating solutions of C-60 in H2CCl2 at room temperature. S olvate crystals are not air stable and spontaneously transform into a hexag onal polymorph of C-60 (a = 10.044(5) Angstrom, c = 16.404(8) A, c/a = 1.63 3(2)) when extracted from the mother liquor at room temperature. Although s olvate formation entails almost no volume change, desolvation enthalpy (59. 2 kJ/mol of solvent) is found to be about twice as high as sublimation enth alpy for pure H2CCl2.