Iodal, or triiodoacetaldehyde, is a halogenated derivative of acetaldehyde with the chemical formula I₃CCHO, it is analogous to chloral and bromal. It is described as a pale yellow liquid with a pungent odour by Leopold Gmelin. It is decomposed to iodoform by potash.^[1] Iodal was discovered and named in 1837.^[2]

Iodal is synthesised from ethanol and iodine with concentrated nitric acid as the catalyst.^[1] Its hydrate was described as water-soluble, white silky crystals.^[3] Like most iodine compounds, Iodal is unstable under sunlight and gives off iodine over time.