▁that ▁contain ▁small ▁amounts ▁of ▁carbon . ▁The ▁chemical ▁behavior ▁of ▁bor on ▁res emb les ▁that ▁of ▁sil icon ▁more ▁than ▁al umin ium . ▁Cry st all ine ▁bor on ▁is ▁chem ically ▁in ert ▁and ▁resist ant ▁to ▁attack ▁by ▁bo iling ▁hydro flu or ic ▁or ▁hydro ch lor ic ▁acid . ▁When ▁fin ely ▁divided , ▁it ▁is ▁attacked ▁slowly ▁by ▁hot ▁concentr ated ▁hydro gen ▁per ox ide , ▁hot ▁concentr ated ▁nit ric ▁acid , ▁hot ▁sul fur ic ▁acid ▁or ▁hot ▁mixture ▁of ▁sul fur ic ▁and ▁chrom ic ▁ac ids . ▁ ▁The ▁rate ▁of ▁ox id ation ▁of ▁bor on ▁depends ▁on ▁the ▁cry st all inity , ▁particle ▁size , ▁pur ity ▁and ▁temperature . ▁Bor on ▁does ▁not ▁react ▁with ▁air ▁at ▁room ▁temperature , ▁but ▁at ▁higher ▁temper atures ▁it ▁burn s ▁to ▁form ▁bor on ▁tri ox ide : ▁ 4 ▁B ▁+ ▁ 3 ▁O 2 ▁→ ▁ 2 ▁B 2 O 3 ▁ ▁Bor on ▁under go es ▁hal ogen ation ▁to ▁give ▁tri hal ides ; ▁for ▁example , ▁ 2 ▁B ▁+ ▁ 3 ▁Br 2 ▁→ ▁ 2 ▁B Br 3 ▁The ▁tr ich lor ide ▁in ▁practice ▁is ▁usually ▁made ▁from ▁the ▁ox ide . ▁ ▁At omic ▁structure ▁Bor on ▁is ▁the ▁light est ▁element ▁having ▁an ▁electron ▁in ▁a ▁p - orb ital ▁in ▁its ▁ground ▁state . ▁But , ▁unlike ▁most ▁other ▁p - elements , ▁it ▁rarely ▁ob e