New crystalline cobalt, nickel, zinc, and mercury halide adducts with polyethers as ligands have been isolated, characterized, and identified as [Co(μ-Cl)₂CoCl₂(glyme)₂] (glyme = 1,2-dimethoxyethane), cis-[CoI₂(H₂O)₂(glyme)₂]²⁺[CoI₄]²⁻, [NiI₂(glyme)₂], [ZnI₂(glyme)], [HgCl₂(glyme)], [CoI₂(diglyme)] (diglyme = bis(2-methoxyethyl)ether), [ZnI₂(diglyme)],...