Boron無delocalized electrons？

Carbon點解會有delocalized electrons？
Diamond: No delocalized electrons
Graphite : Has delocalized eletrons

Both substances are formed by carbon . Graphite is bonded by weak van der Waals force between layers, it is easy to move between layer , the eletrons are delocalized between layers. Diamond is bonded by strong covalent bond , the eletrons are strongly bonded between eletrons , eletrons can not go away.

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Boron 無 delocalized electrons？點解？

It is simiar to my explanation on diamond