#redmercury The name 'red mercury' is a code word used in the USSR nuclear weapons program since the 1950s to describe enriched lithium-6. Lithium-6 has two nuclear weapons uses: as a reactor target for production of tritium, and in the form of lithium-6 deuteride as a thermonuclear weapon material. The most common production process uses large amounts of mercury as chemical agents. The code name originated because mercuric impurities contaminate the lithium- 6 during