Hexa-1,5-diyne
= Hexa-1,5-diyne
The <hydrocarbon> $\mathrm{HC\equiv C-CH_2-CH_2-C\equiv CH}$. Its triple-bond fragments are linear, but the entire <carbon> skeleton need not be. The extended anti conformation has an <inversion centre> at the central bond midpoint and belongs to the <C2h molecular point group>.