The structures of three crystalline solvates, D 5h (1)-C 90 ·CS 2 , D 5h -C 70 ·3CS 2 , and 2(D 5h -C 70 )·3CS 2 , of nanotubular fullerenes have been determined by single crystal X-ray diffraction. Despite the marked tendency for fullerenes to disorder, the carbon cages in all three structures are fully ordered at 100(2) K for D 5h (1)-C 90 ·CS 2 and 90 K for the other two crystals. Moreover, the carbon disulfide molecules are also ordered, except for the case of D 5h (1)-C 90 ·CS 2 , where there is a minor disorder in the solvate location. The molecular packing in D 5h (1)-C 90 ·CS 2 reflects the nanotubular nature of the fullerene component with channels of alternating fullerenes and carbon disulfide molecules running along the crystallographic b axis. The molecular packing arrangements for D 5h -C 70 · 3CS 2 and 2(D 5h -C 70 )·3CS 2 do not show such channels. In D 5h -C 70 ·3CS 2 , the carbon disulfide molecules form chains that snake between the fullerenes and along the crystallographic a axis. In 2(D 5h -C 70 )·3CS 2 , there are two crystallographically distinct fullerene cages, which are segregated into individual layers. Within each layer, the fullerenes show hexagonal close packing and the carbon disulfide molecules form chains that snake between the fullerene layers in a zigzag fashion. The presence of diiodine in solution was essential for the formation of crystals of D 5h -C 70 ·3CS 2 and 2(D 5h -C 70 )·3CS 2 that were suitable for structure determination, although no diiodine was incorporated in these crystals.

Three new polymorphs of C 60 •2S 8 were discovered. The previously known structure (first reported by Roth and Adelmann in 1993 hereby designated as α) crystallizes in space group C2/c with Z = 4 and changes to a triclinic structure (β) in space group P1̅ with Z = 4 when the temperature is decreased below 260 K. The room-temperature structure was reinvestigated, and the new, ordered, lowtemperature structure is described. A new, concomitant, polymorph (γ) crystallizes in space group P2 1 /c with Z = 4 at room temperature and undergoes a phase change to Pc (δ) with Z = 4 when the temperature is decreased below 180 K. As indicated by geometric and temperature factor changes, it is clear that the low-temperature phases represent an increase in the level of order in the arrangement of C 60 molecules. Both of the phase changes are reversible.

Cocrystallization of diiodine and carbon disulfide with the two common fullerenes, C60 and C70, has been examined. The binary cocrystal, C70·I2, readily formed when a solution of diiodine in diethyl ether was layered over C70 dissolved in toluene, chlorobenzene, or 1,2-dichlorobenzene, but no binary cocrystal of diiodine and C60 could be obtained despite persistent efforts. The ternary cocrystal, C70·0.85I2·0.15CS2, which was grown from a carbon disulfide solution of C70 and a benzene solution of diiodine, is isostructural with C70·I2 but has 15% of the diiodine sites replaced with carbon disulfide. In contrast, C70·0.68I2·0.32CS2, which was obtained from diffusion of a cyclohexane solution of diiodine into a carbon disulfide solution of C70, is a unique ternary cocrystal that is not related to any binary cocrystal of C70 with diiodine or carbon disulfide. Crystals of 2C60 ·2.46CS2 ·0.54I2 were obtained from a saturated carbon disulfide solution of diiodine and C60. Black crystals of 2C60 ·2.46CS2 ·0.54I2 form in a different space group from those of the solvate 2C60 ·3CS2 but have a very similar structure. Remarkably, diiodine molecules fractionally replace carbon disulfide in only two of the three independent sites within this crystal.

The single crystal X-ray structures of three well-ordered cocrystals of C 70 with brominated benzenes are examined. The crystals are those of C 70 • C 6 Br 6 •C 7 H 8 , C 70 •C 6 Br 6 •C 6 H 6 , and C 70 •2(1,2,4,5-tetrabromobenzene)•CS 2 . While all three structures exhibit extensive van der Waals interactions, the presence of a wavelike C−Br---Br structural motif is a distinctive part of the cocrystal assembly.In these three crystal structures, it is observed that the Br---Br interactions are a cross between type I and II halogen−halogen bonds. In our hands, this structural motif does not occur in structures with C 60 .

The bowl-shaped hydrocarbon hexakis[(E)-3,3-dimethyl-1-butenyl]benzene (HB) has been cocrystallized with either C 60 or C 70 to form clamshell-like assemblies with the fullerenes residing within the concave surfaces of two HB molecules. The structures of these two crystals have been determined by singlecrystal X-ray diffraction. The HB molecules exhibit back-to-back stacking and close contacts in both cocrystals. This trait is remarkably similar to the packing seen in cases in which fullerenes cocrystallize with M II (OEP), where OEP is the dianion of octaethylporphyrin and M is generally Ni or Co. The C 60 structure features an ordered cage with a disordered solvent position, while the C 70 structure exhibits two orientations of the cage, all other components being ordered.