Successful Rietveld refinements of seven compounds, La2Ti1-xGaxO5-x/2, with x =

0.00, 0.20, 0.50, 0.70, 0.90, 0.95 or 1.00, were performed in order to describe the

solid solubility between orthorhombic (Pnam) La2TiO5 and monoclinic (P21/c)

La4Ga2O9. The space-group change was a consequence of ordering of the oxygen

vacancies that became more numerous as Ga was substituted for Ti. The lengths of

the cell edges obeyed Vegard's rule.

Order-Disorder of Oxygen Anions and Vacancies in Solid Solutions of La2TiO5 and

La4Ga2O9. M.Kasunic, A.Meden, S.D.Skapin, D.Suvorov, A.Golobic: Acta

Crystallographica B, 2009, 65[5], 558-66