Raman Spectroscopy of Potassium Titanates: Their Synthesis, Hydrolytic Reactions, and Thermal Stability

The majority of the potassium titanates described in the literature were synthesized, and their Raman spectra recorded. The identity of the compounds K 2 TiO 3 , K 2 Ti 2 O 5 , K 2 Ti 4 O 9 , K 2 Ti 6 O 13 , and K 2 Ti 8 O 17 was confirmed by x-ray diffraction. Raman spectroscopy was then used to study the hydrolysis, under different conditions, of K 2 Ti 2 O 5 and of K 2 Ti 4 O 9 . On drying of the hydrolysis products, the following species were found to form: K 2 (H 2 O) 0.66 Ti 8 O 16 (OH) 2 , K 1.33 (H 2 O) 0.33 Ti 4 O 8.33 (OH) 0.67 , and H 2 Ti 8 O 17 . On ignition at temperatures of 500–600°C these species converted, respectively, to K 2 Ti 8 O 17 , K 2 Ti 6 O 13 , and TiO 2 (B). Raman spectroscopy was used to establish that (1) K 6 Ti 4 O 11 consists of a mixture of K 2 TiO 3 and a new compound K 4 Ti 3 O 8 ; (2) K 2 Ti 3 O 7 consists of a mixture of K 2 Ti 2 O 5 and K 2 Ti 4 O 9 , and (3) K 2 Ti 5 O 11 consists of a mixture of K 2 Ti 4 O 9 and K 2 Ti 6 O 13 . The temperature of decomposition and the identity of the products of the thermal decomposition of K 2 Ti 8 O l7 , K 2 Ti 4 O 9 , K 2 Ti 2 O 5 , and K 4 Ti 3 O 8 were determined by Raman spectroscopy. The XRD data of the newly identified compounds are reported.