▁or ▁ph osph onic ▁acid , ▁ ▁( or ▁), ▁a ▁di pro t ic ▁acid ▁( with ▁only ▁two ▁acid ic ▁hyd rog ens ). ▁ ▁Its ▁sal ts ▁and ▁est ers ▁are ▁called ▁ph osph ites ▁or ▁ph os phon ates . ▁ ▁Ox id ation ▁state ▁+ 4 ▁ ▁Hyp oph osph or ic ▁acid , ▁ ▁( or ▁– ). ▁All ▁four ▁hyd rog ens ▁are ▁acid ic . ▁Its ▁sal ts ▁and ▁est ers ▁are ▁hyp oph osph ates . ▁ ▁Ox id ation ▁state ▁+ 5 ▁The ▁most ▁important ▁members ▁of ▁this ▁group ▁are ▁the ▁ph osph or ic ▁ac ids , ▁where ▁each ▁ph osph orus ▁atom ▁bond ed ▁to ▁four ▁o xygen ▁atoms , ▁one ▁of ▁them ▁through ▁a ▁double ▁bond , ▁arranged ▁as ▁the ▁corners ▁of ▁a ▁t etra hed ron . ▁Two ▁or ▁more ▁of ▁these ▁ ▁t etra hed ra ▁may ▁be ▁connected ▁by ▁shared ▁single - b ond ed ▁o xy gens , ▁forming ▁linear ▁or ▁branch ed ▁ch ains , ▁cycles , ▁or ▁more ▁complex ▁structures . ▁The ▁single - b ond ed ▁o xygen ▁atoms ▁that ▁are ▁not ▁shared ▁are ▁completed ▁with ▁acid ic ▁hydro gen ▁atoms . ▁Their ▁generic ▁formula ▁is ▁H n − x + 2 P n O 3 n − x + 1 , ▁where ▁n ▁is ▁the ▁number ▁of ▁ph osph orus ▁atoms ▁and ▁x ▁is ▁the ▁number ▁of ▁fundamental ▁cycles ▁in ▁the ▁mole c ule ' s ▁structure . ▁ ▁These ▁ac ids