(a) Heavy water is injurous to human beings, plants and animals since it slows down the rates of reactions occuring in them. (b) Heavy water reacts with aluminium carbide forming deuteromethane.
Al4C3
aluminiumcarbide
+12D2O→4Al(OD)3+
CD4
deuteromethane
(c) In interstitial hydrates or deuterates, water molecules are present in interstitial sites on voids in the crystal lattice. e.g., BaCl2.2H2O and similarly BaCl2.2D2O are interstitial compounds.