Tubulanes: carbon phases based on cross-linked fullerene tubules

Structure and properties are calculated for five predicted carbon phases, called tubulanes, which are shown to be possible reaction products of single-layer and multiple-layer carbon tubules. Each carbon atom is equivalent and in a modified sp ³ state in these phases which contain column structures that are directly related to those in either armchair or zig-zag carbon tubules. One such phase has a predicted bulk modulus which is within 6% of that of diamond, and a predicted heat of formation which is much lower than for either the C ₆₀ fullerene or other previously characterized no-diamond-like phases containing only sp ³ carbons.