Layer−Anion Interactions in Magnesium Aluminum Layered Double Hydroxides Intercalated with Cobalticyanide and Nitroprusside

The interactions of cobalticyanide and nitroprusside with magnesium aluminum layered double hydroxide are investigated using oriented infrared spectroscopy together with powder X-ray diffraction. Cobalticyanide is known to intercalate into layered double hydroxides in the same manner as ferrocyanide, with its 3-fold rotational axis perpendicular to the cation sheets. The intercalated cobalticyanide anion shows a small yet observable deviation from local O_h symmetry, causing small differences between its oriented and nonoriented infrared spectra. Nitroprusside is shown to intercalate into 2:1 Mg:Al LDH with decomposition to form intercalated ferrocyanide and nitrosyl groups of an unidentified nature.