Iron trifluoride FeF3 was possible to be applied as CVD precursor for the growth of pure Fe films (>99% purity), however it needs high growth temperatures (from 750 to 1150°C, but generally around 1000 °C).
The mechanism of decomposition is 2-step defluorination mechanism:
2 FeF3 → 2 FeF2 + F2 (in the gas-phase)
FeF2 → Fe + F2 (on the surface)
Iron diiodide FeI2 was reported to be potentially applicable as Fe CVD precursor.