Magnesium dititanate (MgTi2O5) with pseudobrookite structure: a review

Magnesium dititanate (MgTi2O5, MT2) has been synthesized since the early 1930s. It has the pseudobrookite structure (general formula Me3O5), corresponding to the Mg-enriched artificial endmember of the Fe2TiO5 (pseudobrookite)-FeTi2O5 (ferropseudobrookite)-Mg0.5Fe0.5Ti2O5 (armalcolite) solid solution. Since MgTi2O5 has relativity high thermal stability among pseudobrookite-type phases, it is expected to be a well-balanced low-thermal-expansion material. Here we review both the historical and recent studies on MgTi2O5, particularly on its crystal structure, cation order-disorder, physical properties and synthesis methods. (topical review)