Chemistry - Complete Pblock- Question with Solution | TestHub

In diamond, all carbons are$\mathrm{s}{\mathrm{p}}^3$hybridised and hence bond lengths are similar to carbon-carbon single bonds.
Graphite,${\mathrm{C}}_{70}$and${\mathrm{C}}_{60}$forms of carbon have delocalisation of electrons which leads to double bond characteristics. Hence, their bond lengths are in between carbon-carbon single and double bonds.
Hence, diamond with only single bond character will be have the longest bond.