Sol‐Gel Process for the Preparation of Ba₂Ti₉O₂₀ and BaTi₅O₁₁

Barium titanate precursors with Ba/Ti ratio 2:9 and 1:5 were prepared by first hydrolyzing titanium alkoxide and then mixing the resulting titania sol with a barium alkoxide‐methanol solution. After drying, the xerogels of the precursors of barium titanates were sintered at temperatures from 700°C (4 h) to 1200°C (110 h or longer). Characterization of the product was performed using X‐ray diffraction and laser Raman spectroscopy. At 700°C, BaTi₅O₁₁ was formed from the 1:5 precursor and a two‐phase mixture of BaTi₂O₅ and BaTi₅O₁₁ was formed from the 2:9 precursor. After prolonged heating at 1200°C, the latter mixture converted to a single‐phase material, Ba₂Ti₉O₂₀.