超重水 超重水（Tritium oxide），是一种无机化合物，由两个氚和一个氧组成，故又称一氧化二氚，其化学式为T₂O或H₂O。氚是氢的放射性同位素，该原子由原子核由质子和两个中子，半衰期约12年，水在地球上的总重大约是一百三十六京吨，超重水在天然水中极其稀少，其比例不到十亿分之一。若要制取1公斤的超重水需要超过100万吨的天然水和大量的电能，因此超重水成本比黄金高上百倍，比重水提取成本高上万倍。

超重水不应该和重水混淆，差别于超重水是T₂O或H₂O；而重水是D₂O或H₂O。

Tritiated water is a radioactive form of water where the usual hydrogen atoms are replaced with tritium. In its pure form it may be called tritium oxide (T₂O or H₂O) or super-heavy water. Pure T₂O is corrosive due to self-radiolysis. Diluted, tritiated water is mainly H₂O plus some HTO (HOH). It is also used as a tracer for water transport studies in life-science research. Furthermore, since it naturally occurs in minute quantities, it can be used to determine the age of various water-based liquids, such as vintage wines.