Computational study of the hafnium (IV) ion in aqueous solution

The ab initio quantum mechanical charge field (QMCF) molecular dynamics (MD) formalism was used to evaluate structure and dynamics of the monomeric hydrated tetravalent hafnium. The ion forms three hydration shells and no hydrolysis reaction occurred during the simulation time of 7 ps. Eight water molecules coordinate in a more or less well-defined square antiprismatic geometry at the hafnium ion, as visible from the O–Hf–O angular distribution function, with a Hf (IV)–O bond length of 2.26 Å and a bond force constant of 212 N/m, which classifies this bond as the strongest ion–water bond known so far.