Neutral and anionic superhalogen hydroxides

► The superhalogen hydroxides and their anions were studied at the CCSD(T)/6-311++G(3df,3pd) level. ► All anionic superhalogen hydroxides were found to be thermodynamically stable. ► The VDE values calculated for the M(OH)k+1- anions exceed 4 eV in all cases. ► The largest VDEs were found for the Al(OH)4- (6.07 eV) and Ga(OH)4- (6.21 eV).