Di-mu-sulfito-bis[(4,4'-dimethyl-2,2'-bipyridine)zinc(II)] dihydrate and poly[[aqua(1,10-phenanthroline)zinc(II)]-mu3-sulfito-zinc(II)-mu3-sulfito].

Two different zinc sulfite compounds have been prepared through the decomposition of pyrosulfite-dithionite ions in aqueous solution, viz. a dimeric complex, di-mu-sulfito-kappa3O,O':O'';kappa3O:O',O''-bis[(4,4'-dimethyl-2,2'-bipyridine-kappa2N,N')zinc(II)] dihydrate, [Zn2(SO3)2(C12H12N2)2].2H2O, (I), which was solved and refined from a twinned sample, and an extended polymer, poly[[aqua(1,10-phenanthroline-kappa2N,N')zinc(II)]-mu3-sulfito-kappa2O:O':O''-zinc(II)-mu3-sulfito-kappa3O:O:O'], [Zn2(SO3)2)(C12H10N2)(H2O)]n, (II). In (I), the dinuclear Zn(II) complex has a center of symmetry. The cation is five-coordinate in a square-pyramidal arrangement, the anion fulfilling a bridging chelating role. Compound (II) comprises two different zinc units, one being five-coordinate (square pyramidal) and the other four-coordinate (trigonal pyramidal), and two independent sulfite groups with different binding modes to the cationic centers.