The invention comprises a process of cyclic thermochemical dissociation of oxides catalysed by a metal compound of general structural formula MX, wherein M is a metal; X is none or oxygen or halogen, the said oxygen or halogen present in moles equivalent to M; comprising at least a step of recovering anhydrous metal halide from a process stream and recycling the metal halide or thermally decomposing the same to metal and halogen for recycling. The oxide selected for dissociation may be carbon-dioxide or water. After dissociation of oxides, the products of the reaction undergo a series of reactions comprising a reaction with a halogen, formation of metal halides and oxyhalides as intermediates, thermal decomposition of metal oxyhalides to recover metal oxides and Iodine for recycle, recovery of metal halides for recycle and thermal decomposition of metal halides to metal and halogen for recycle in the said cyclic process.