NATURAL ISOMERS OF FULLERENES FROM C4 TO C20

We have systematized possible ways of forming the isomers of mini-fullerenes, namely elementary fullerenes: tetrahedron C-4, triangular prism C-6, cube C-8, pentagonal prism C-10, hexagonal prism C-12, as well as their derivatives, which were obtained by joining elementary fullerenes. Combined with the graph analysis, this approach allows obtain a clear knowledge of their structure. Among them there are barrel-shaped fullerenes: C-12, C-16, C-20; tetrahedral ones C-12 and C-16; bi-shamrocks C-14 and C-18, bipyramids C-14 and C-18; regular and irregular dodecahedrons C-20 as well as intermediate compounds. The three simplest elementary fullerenes, C-4, C-6, C-8; have only electronic isomers and no space atomic isomers at all. After a cube, the next in size carbon fullerene C-10 is a pentagonal prism. We have designed an isomer of it by fusion of a tetrahedron and a triangular prism. For the pentagonal prism shape fullerene the energy lies in the range from 974 to 2464 kJ/mol, for the hybrid of a tetrahedron and a triangular prism does in the range from 1396 to 2433 kJ/mol; it depends both on the number of single and double bonds as well as on their position in space. Fullerene of twelve carbon atoms C-12 produces four isomers: a hexagonal prism, a barrel-shape fullerene, a truncated tetrahedron and a tetra-penta octahedron. They have different energies depending on the number of single and double bonds and their position in space. In a like manner other fullerenes studied, C-14, C-16, C-18 and C-20, have two or three isomers with different energies.