Mg(H₂PO₄)₂.4H₂O

Magnesium bis(dihydrogenorthophosphate) tetrahydrate contains four-membered rings made up of two [PO₄] tetrahedra and two [MgO₆] octahedra sharing corners. These rings are joined through the [MgO₆] octahedra and alternately twisted by approximately 90° to form an infinite linear chain.

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