The thermal decomposition of barium trifluoroacetate thin films under different atmospheres is presented. Thermogravimetry and evolved gas analysis have been used for this in situ analysis. We focus our attention on the different behavior exhibited by films when compared to powders. The decomposition of barium trifluoroacetate is altered due to the faster out-diffusion of the product reaction:CF2. After barium trifluoroacetate decomposition a stable intermediate, barium fluoride, is formed. The decomposition of barium fluoride is diffusion controlled and depends on water partial pressure. (C) 2013 Elsevier B.V. All rights reserved.