▁with ▁relatively ▁little ▁overlap ▁between ▁the ▁val ence ▁band ▁and ▁the ▁condu ction ▁band . ▁Thus , ▁z inc ▁is ▁close ▁to ▁the ▁boundary ▁between ▁met all ic ▁and ▁metal lo id ▁elements , ▁which ▁is ▁usually ▁placed ▁between ▁gal li um ▁and ▁g erman ium , ▁though ▁gal li um ▁particip ates ▁in ▁semi - con duct ors ▁such ▁as ▁gal li um ▁ar sen ide . ▁ ▁Z inc ▁and ▁cad m ium ▁are ▁electro pos itive ▁while ▁mer cur y ▁is ▁not . ▁As ▁a ▁result , ▁z inc ▁and ▁cad m ium ▁metal ▁are ▁good ▁reducing ▁agents . ▁The ▁elements ▁of ▁group ▁ 1 2 ▁have ▁an ▁ox id ation ▁state ▁of ▁+ 2 ▁in ▁which ▁the ▁ ions ▁have ▁the ▁rather ▁stable ▁d 1 0 ▁electronic ▁configuration , ▁with ▁a ▁full ▁sub - shell . ▁However , ▁mer cur y ▁can ▁easily ▁be ▁reduced ▁to ▁the ▁+ 1 ▁ox id ation ▁state ; ▁usually , ▁as ▁in ▁the ▁ion ▁, ▁two ▁mer cur y ( I ) ▁ ions ▁come ▁together ▁to ▁form ▁a ▁metal - met al ▁bond ▁and ▁a ▁diam agnet ic ▁species . ▁Cad m ium ▁can ▁also ▁form ▁species ▁such ▁as ▁[ C d 2 Cl 6 ] 4 − ▁in ▁which ▁the ▁metal ' s ▁ox id ation ▁state ▁is ▁+ 1 . ▁Just ▁as ▁with ▁mer cur y , ▁the ▁formation ▁of ▁a ▁metal - met al ▁bond ▁results ▁in ▁a ▁diam agnet ic ▁comp ound ▁in ▁which ▁there ▁are ▁no ▁un