Numbering of Fullerenes (IUPAC Recommendations 2004)

3.2.2. Systematic numbering for (C48-Oh)[4,6,8]fullerene

Continued from 3.2.1. Systematic numbering for (C24-Oh)[3,8]fullerene


3.2.2. Systematic numbering for (C48-Oh)[4,6,8]fullerene (Fig. 16)
[CAS Reg. No. 145985-79-1, as fulleride(2-)].

This fullerene, made up only of 8,6,4 atoms, posesses three symmetry-equivalent C4 axes (Fig. 16a), four symmetry-equivalent C3 axes (Fig. 16b), and six symmetry-equivalent C2 axes (not shown: the axes pass through the midpoints of opposite four-membered rings). When one of the C4 axes is used as the reference axis (Fig. 16a) and the pathway begins along a bond shared by a an eight- and a six-membered ring, the numbering becomes discontiguous at position 40. When, using the same axis, a bond shared by an eight- and a four-membered ring is selected to begin the numbering (namely, C-2 to C-3 in Fig. 16a), the discontiguity occurs at position 24. The numbering obtained using one of the C3 axes as the reference axis and starting along a bond shared by an eight- and a six-membered ring is shown in Fig. 16b. In this case the discontiguity occurs at position 42. Using the same axis and starting along a bond shared by a six- and a four- membered ring (namely, C-2 to C-3 in Fig. 16b), the numbering becomes discontiguous at position 24. The use of a C2 axis leads to numberings discontiguous at positions with lower locants. Therefore, on the basis of Fu-3.2.1a the numbering shown in Fig. 16b is preferred. According to Fu-3.2.4a, the numbering resumes at position 43 which is connected to 41, and then continues contiguously to position 48 according to Fu-3.2.4b.

Fig. 16. Systematic numbering of (C24-Oh)[3,8]fullerene


Continued with 3.2.3. (C32-Oh)[4,6]fullerene
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