Microwave irradiation power (90, 180, 270 or 360 W) determines the composit
ion and the structure of the compounds obtained when pH is increased, decre
ased or maintained constant during preparation. Although in all cases the X
-ray diffraction patterns show that the obtained compounds are hydrotalcite
-like, the surface areas (40 up to 240 m(2)/g) as well as other microcrysta
lline compounds have to be inferred, such as Al(OH)(3) or Mg(OH)(2).