#hydrogen__H__atomic_number_1__atomicnumber1  a nonmetallic univalent element that is normally a colorless and odorless highly flammable diatomic gas; the simplest and lightest and most abundant element in the universe
  supertype:  chemical_element  gas
  substance of:  water
  subtype:  tritium  a radioactive isotope of hydrogen; atoms of tritium have three times the mass of ordinary hydrogen atoms

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