Synthesis and thermal decomposition of magnesium hydroxide nitrates

Abstract A magnesium hydroxide nitrate, Mg2(OH)3NO3, with lattice parameters ao = 3.16 and co = 6.98 A has been prepared by precipitation from Mg(NO3)2 and NaOH solutions. Its hydrothermal treatment in the mother liquor at 150°C leads to crystallization of a new phase with lattice parameters ao = 5.46 and co = 6.96 A. Transmission electron microscope and selected area electron diffraction studies have shown that the formation of the MgO phase during the decomposition of Mg2(OH)3NO3, is a topotactic process. On the basis of the general formulae, lattice parameters and decomposition mechanisms, it has been assumed that the structures of the magnesium hydroxide nitrates are related to the single-layered brucite-like type.