Quantum chemical investigation of the structure of a water dimer coordinated with the M/sup n+/-OH/sub 2/. OH/sub 2/ cation (M/sup n+/ = Na/sup +/, Mg/sup 2 +/, Be/sup 2 +/, Al/sup 3 +/)

Our aim was to obtain structural characteristics of the M/sup n+/-OH/sub 2/...OH/sub 2/ system in the course of optimization of a wide set of geometrical parameters. As a limit to variation in the parameters, we used the assumption that the M, O/sub 1/, O/sub 2/, H/sub 1/, H/sub 2/ atoms lie in the same plane and the O/sub 1/O/sub 2/H/sub 3/ and O/sub 1/O/sub 2/H/sub 4/ angles are the same. We examined the cations: M/sup n+/ = Na/sup +/, Mg/sup 2 +/, Be/sup 2 +/, Al/sup 3 +/ that give aqueous solutions characterized by different acid-base properties.