The solvothermal method has recently been extended from zeolite synthesis to the formation of condensed inorganic solids, which find uses in diverse areas due to properties such as ionic-conductivity, solid-state magnetism, giant magnetoresistance, low thermal expansion and ferroelectricity. This offers specific advantages over the traditional ceramic synthetic routes to inorganic solids and these are highlighted with examples from the recent literature, and the efforts focussed on determining the formation mechanism of solids from the heterogeneous mixtures used in solvothermal procedures are discussed.

The brucite-like Mg²⁺/Al³⁺ layered double hydroxide (LDH) was synthesized by using the coprecipitation method and calcined at a variety of temperatures. The starting LDH and the calcination products (mixtures of binary oxides and spinels) were characterized by X-ray diffraction, IR spectroscopies and thermogravimetric analysis. These techniques allowed us to confirm that the double hydroxide possesses a brucite-like structure in which cations are octahedrally arranged. At moderate temperatures, the calcination products have a MgO-like structure where Al ions are dissolved in the lattice to form a solid solution. Calcination at high temperatures (up to 1000 °C) yields a mixture of well-crystallized phases corresponding to MgO and MgAl₂O₄ (spinel). The reconstruction of layered double hydroxides from material calcined at 400 °C has been studied in situ by time resolved energy dispersive X-ray diffraction (EDXRD). Kinetic data for the reaction have been determined and modelled using the Avrami–Erofe'ev nucleation–growth model, consistent with the process taking place by dissolution of the starting material and crystallisation of the LDH from the solution.

The thermal behaviour of the nanoporous iron(III) terephthalate MIL-53 is in stark contrast to its chromium and aluminium analogues which show an expansion of the cell during dehydration; with iron, reversible dehydration occurs via evolution of the structure through a highly distorted metastable anhydrous phase to a more regular phase above 423 K in which pore volume remains approximately constant.