ys ▁the ▁oct et ▁rule ▁and ▁usually ▁places ▁only ▁six ▁electrons ▁( in ▁three ▁mole cular ▁orbit als ) ▁onto ▁its ▁val ence ▁shell . ▁Bor on ▁is ▁the ▁prototype ▁for ▁the ▁bor on ▁group ▁( the ▁I UP AC ▁group   1 3 ), ▁although ▁the ▁other ▁members ▁of ▁this ▁group ▁are ▁met als ▁and ▁more ▁typical ▁p - elements ▁( only ▁al umin ium ▁to ▁some ▁extent ▁shares ▁bor on ' s ▁a version ▁to ▁the ▁oct et ▁rule ). ▁ ▁Chem ical ▁comp ounds ▁ ▁In ▁the ▁most ▁familiar ▁comp ounds , ▁bor on ▁has ▁the ▁formal ▁ox id ation ▁state ▁III . ▁These ▁include ▁ox ides , ▁sul f ides , ▁nit rides , ▁and ▁hal ides . ▁ ▁The ▁tri hal ides ▁adopt ▁a ▁plan ar ▁trig onal ▁structure . ▁These ▁comp ounds ▁are ▁Lewis ▁ac ids ▁in ▁that ▁they ▁readily ▁form ▁ad duct s ▁with ▁electron - pair ▁don ors , ▁which ▁are ▁called ▁Lewis ▁bases . ▁For ▁example , ▁flu or ide ▁( F − ) ▁and ▁bor on ▁trif lu or ide ▁( BF 3 ) ▁combined ▁to ▁give ▁the ▁t etra flu or ob or ate ▁an ion , ▁B F 4 − . ▁Bor on ▁trif lu or ide ▁is ▁used ▁in ▁the ▁pet ro chem ical ▁industry ▁as ▁a ▁catal yst . ▁The ▁hal ides ▁react ▁with ▁water ▁to ▁form ▁bor ic ▁acid . ▁ ▁Bor on ▁is ▁found ▁in ▁nature ▁on ▁Earth ▁almost ▁entirely ▁as ▁various ▁ox ides ▁of ▁B (