A cubic dipole lattice of water molecules trapped inside carbon cages.

We report the crystal structure and dielectric properties of a pure H2O@C60 crystal at low temperature. The caged water molecules free from the hydrogen bonds rotate even at 8 K. The antifreeze rotating water molecules respond to an external electric field due to their permanent dipole moment.

Rock-salt-type crystal of thermally contracted C60 with encapsulated lithium cation.

Rock solid: fullerene-encapsulated Li(+) (Li(+)@C(60)) is an alkaline cation owing to the spherical shape and positive charge. Li(+)@C(60) crystallizes as a rock-salt-type crystal in the presence of PF(6)(-). The orientations of C(60) and PF(6)(-) (orange) are perfectly ordered below 370 K, and Li(+) (purple) hops within the cage. At temperatures below 100 K two Li(+) units are localized at two polar positions within each C(60) .