Thermal decomposition of metal-organic precursors for the mixed oxide BaBiO3 was studied using TG and EGA. Precursors produced by polyesterification of bifunctional acids with ethylene glycol (Pechini
process) decomposed about 100°C higher than those without the diol. BaCO3 was identified by IR and XRD as a reaction intermediate. EGA proved that the amount of BaCO3 was below 10% of the total barium, and that the barium exists mainly as a nitro-compound up to 650°C. Phase-pure BaBiO3 with a moderately high surface area (1.4 m2/g) could be synthesised from a citrate precursor by the Pechini process at around 850°C.