Structural isomers of M(dca)2 molecule-based magnets. Crystal structure of tetrahedrally coordinated sheet-like β-Zn(dca)2 and β-Co/Zn(dca)2, and the octahedrally coordinated rutile-like α-Co(dca)2, where dca– = dicyanamide, N(CN)2−, and magnetism of β-Co(dca)2

β-Zn(dca)2 and 0.12% Co(II) doped β-Zn(dca)2 contain tetrahedrally coordinated metal ions within a corrugated sheet network structure dca = dicyanamide, N(CN)2–, β-Co(dca)2 is a spin-canted antiferromagnet (TN = 9 K), while the rutile-like octahedral α-form is a ferromagnet.