Crystal structure of the magnesium salt of the herbicide 2,4-D: penta­aqua­[(2,4-di­chloro­phenoxy)acetato-κO]magnesium (2,4-di­chloro­phen­oxy)acetate hemihydrate

In the crystal structure of the title magnesium salt of the phen­oxy herbicide (2,4-di­chloro­phen­oxy)acetic acid (2,4-D), [Mg(C(8)H(5)Cl(2)O(3))(H(2)O)(5)](C(8)H(5)Cl(2)O(3))·0.5H(2)O, the discrete cationic MgO(6) complex unit comprises a carboxyl­ate O-donor from a monodentate 2,4-D anionic ligand and five water mol­ecules, resulting in a slightly distorted octa­hedral coordination sphere. The free 2,4-D anions are linked to the complex units through duplex water–carboxyl­ate O—H⋯O hydrogen bonds through the coordinating water mol­ecules. In the crystal, inter-unit O—H⋯O hydrogen-bonding inter­actions involving coordinating water mol­ecules as well as the solvent water mol­ecule (occupancy 0.5) with carboxyl­ate O-atom acceptors, give a layered structure lying parallel to (001), in which π–π ligand–cation inter­actions [minimum ring centroid separation = 3.6405 (17) Å] and a short O—H⋯Cl inter­action are also found.