The (2) Sigma(+) states of HBeO, HMgO, and HCaO have been studied at the CASSCF level with a basis set of at least triple-zeta plus double polarization quality. The correlation treatment includes the nine valence electrons and ten orbitals resulting in an active space denoted by (622). The optimized structures of HMO (M=Be, Mg, and Ca) are all linear and the energy of HMO lies around 250 kJ/mol (2.6 eV) above that of MOH. The M-O bond length in HMO is predicted to be longer than that in the corresponding MOH by amounts ranging from 0.01 Angstrom to 0.05 Angstrom. The M-O stretching frequencies are very similar for the two structures. The H-M bond lengths and stretching frequencies in HMO are very similar to the same properties in the corresponding diatomic molecule. Analysis of the electronic structures suggests that HBeO has two polarized covalent bonds formed from the sp hybrids of Be; HMgO has one covalent bond (between H and Mg) and one ionic bond and can be viewed as (HMg)O-+(-), HCaO has two ionic bonds represented by H-Ca2+O-.