In the last century a lot of new findings were reported in the field of chlorine hydrate - the oldest known compound belonging to the so called gas hydrates. Chlorine hydrate was a very interesting compound which encages an elemental chlorine molecule in a water clathrate cage causing changes in the reactivity of the chlorine and ensuring storage in solid phase at room temperature even at mild overpressures (6 atm). Chlorine hydrate, however, decomposes at atmospheric pressure around 8°C. It therefore acts as a solid phase carrier for chlorination with gaseous chlorine in aqueous medium, e.g. as battery chlorine electrode material, chlorinating and disinfecting agents etc. This review summarizes the investigation results from the oldest publication of Davy in 1811 up to the beginning of the decade, and some unpublished new results as well.