SOLID-STATE STUDIES ON C-60 SOLVATES GROWN FROM N-HEPTANE

Crystallographic and thermodynamic experiments show that crystalline C -60 obtained by slow evaporation of solutions in n-heptane is a C-60, n-heptane 1:1 solvate. Its lattice is hexagonal, Lane class 6/mmm, wit h a=10.00(4)Angstrom and c=10.16(1)Angstrom. No transition is observed at temperatures higher than 100 K, and desolvation into fee C-60 occu rs at about 360 K with Delta H=+43.5 J g(-1), close to the sublimation enthalpy for pure n-heptane. Another binary compound, presumably a po lymorph of the former, is sometimes obtained by rapid evaporation of t oluene +n-heptane mixtures. Its lattice is orthorhombic, Immm, with a= 10.07 Angstrom, b=10.22 Angstrom and c=48.9 Angstrom.