Magnesium iodide-4,4'-bipyridine-water (1/3/4) and strontium iodide-4,4'-bipyridine-propan-1-ol (1/2.5/2).

Both of the title compounds, catena-poly[[[tetraaquamagnesium(I)]-micro-4,4'-bipyridine-kappa(2)N:N'] diiodide bis(4,4'-bipyridine) solvate], [[Mg(C(10)H(8)N(2))(H(2)O)(4)]I(2).2C(10)H(8)N(2)](n), (I), and catena-poly[[[micro-4,4'-bipyridine-bis[diiodobis(propan-1-ol)strontium(I)]]-di-micro-4,4'-bipyridine-kappa(4)N:N'] bis(4,4'-bipyridine) solvate], [[Sr(2)I(4)(C(10)H(8)N(2))(3)(C(3)H(8)O)(4)].2C(10)H(8)N(2)](n), (II), are one-dimensional polymers which are single- and double-stranded, respectively, the metal atoms being linked by the 4,4'-bipyridine moieties. The Mg complex, (I), is [cis-[(H(2)O)(4)Mg(N-4,4'-bipyridine-N')((2/2))]](( infinity | infinity ))I(2).4,4'-bipyridine and Mg has a six-coordinate quasi-octahedral coordination environment. The Sr complex, (II), is isomorphous with its previously defined Ba counterpart [Kepert, Waters & White (1996). Aust. J. Chem. 49, 117-135], being [(propan-1-ol)(2)I(2)Sr(N-4,4'-bipyridine-N')((3/2))](( infinity | infinity )).4,4'-bipyridine, with the I atoms trans-axial in a seven-coordinate pentagonal-bipyramidal Sr environment.