Layered Double Hydroxides Structure, Properties and Uses

3 Layered Double Hydroxides Structure, Properties and Uses 

Layered double hydroxides are synthetic or natmal hydroxides with two or more different cations in the layers and with anions in the interlayer domains. They are also known as anionic clays, when compared with cationic clays, which host cations in the interlayer space. The most popular name is hydrotalcite-type compounds, as hydrotaldte is the most abundant mineral in Nature showing this structme. They are less abundant in 

Nature than cationic clays, but can be easily prepared and they are not expensive (obviously depending on their chemical composition). 

X from the formula above, x = M 7(M ++M ). The interlayer is rather disordered, with anions and water molecules randomly located with a quasi-liquid behaviour. The hydroxyl groups of the brucite-like layers are hydrogen bonded to the interlayer carbonate anions directly and via water molecules [21]. The interlayer water molecules can be easily removed on heating without destroying the layered structure, although changes in the stacking sequence can occur [22]. 

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