The　interactions　of　β-D-ribose　(RI)　with　metal　cations　in　groups　Ia(Li+,Na+,K+,Rb　+,Cs+),Ib　(Cu+,Ag+,Au+),　IIa　(Mg2+,Ca2+,Sr2+,Ba2+)　and　IIb　(Zn2+,Cd2+,Hg2+)　were　studied　at　the　Hartree-Fock　and　MP2　levels　employing　all　electron　(AE)　and　pseudopotential　treatments.　Relativistic　effective　core　potentials　(RECP)　were　used　for　all　the　ions,　with　the　exception　of　Li+.　AE　and　RECP　treatments　were　tested　for　the　Na+,K+,Cu+,Mg2+,Ca2+　and　Zn2+　complexes;　good　agreement　between　the　results　of　AE　and　RECP　suggests　that　pseudopotentials　can　be　used　with　confidence　also　for　heavy　metal　cations.　However,　in　order　to　ensure　the　precision　of　computation,　EDEF　and　EBSSE　must　be　taken　into　account.　The　deformation　of　β-D-ribose　caused　by　bivalent　ions　are　more　serious　than　those　caused　by　monovalent　ions.　Stabilization　energies(Δ　E)　and　interaction　Gibbs　energies(Δ　G)　of　complexes　with　bivalent　ions　are　smaller　than　those　with　monovalent　ions.　Therefore,　the　interaction　between　bivalent　ions　and　β-D-ribose　is　stronger　than　that　between　monovalent　ions　and　β-D-ribose.　And　in　the　same　group　the　stability　of　complexes　decreases　with　increasing　atomic　number　of　the　metal　ions　(except　the　Au+-RI　complex),　because　Δ　E　and　Δ　G　added　with　increasing　atomic　number　of　the　metal　ions.