This compound is prepared by treatment of NaBAr′ in diethyl ether (EtO) with hydrogen chloride:
: NaBAr′  +  HCl +  2 EtO  →   [H(OEt)]  +  NaCl
NaBAr′ is soluble in diethyl ether, whereas sodium chloride is not. Precipitation of sodium chloride thus drives the formation of the oxonium acid compound, which is isolable as a solid.