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Q.
Two types of carbo-carbon covalent bond lengths are present in
Chemical Bonding and Molecular Structure
Solution:
diamond ( $1.54 \,\mathring{A}$ )
graphite $(1.42 \,\mathring{A} ) \cdot\left(\perp^{r}\right.$ to the sheets there is no covalent bonding)
$C _{60}(1.45 \,\mathring{A}$ and $1.3 \,\mathring{A} )$
benzene ( $1.36 \,\mathring{A}$ ).