… deuterium (stable hydrogen isotope) which falls in heading 28.45 , and tritium (radioactive hydrogen isotope) which falls in heading 28.44 . (B) RARE GASES The term “rare gases” (inert gases) … under pressure. Radon is a radioactive inert gas of heading 28.44 formed by the radioactive decay of radium. (C) OTHER …
… : (a) Unmixed, non‑sintered metal carbides ( heading 28.49 ). (b) Prepared but non‑sintered metal carbide … abrasion resistant parts of machines, of cermets ( Chapter 84 ). …