Barium cerate crystals of 1.5 mm diameter could be grown from melt solution
s containing barium chloride, barium oxide (from thermolysis of barium carb
onate), and cerium(IV) oxide. The maximum size of the crystals is limited b
y the low solubility of cerium(IV) oxide in the barium chloride melt (ca. 0
.1 Mol%). The flux can be removed by leaching the melt with water. Acid sol
utions must not be used to avoid decomposition of the barium cerate crystal
s. Neither congruent melting or incongruent decomposition of the BaCeO3 cry
stals could be found up to 1580 degrees centigrade.