Preparation of a colloidal dispersion of a rare earth perovskite, useful in catalytic applications

Preparation of a colloidal dispersion of a rare earth compound of a perovskite structure comprising a bimetallic oxide, the dispersant being water, an organic solvent or a combination of water and an organic solvent. The colloid is of a perovskite structure of formula (1) : LnBO3 : (1) Ln = rare earth other than Ce alone; B = an element from groups comprising elements of atomic number 22 - 31, 40 - 51 , 73 - 83 and Al. Independent claims are also included for the preparation of the dispersions and a solid composition obtained from the dispersion.