Noble‐Gas Compounds

AbstractNoble‐gas reactivity was discovered on March 23, 1962 when Neil Bartlett (1932–2008) showed that xenon gas was oxidized by PtF6. The product obtained by Bartlett was initially formulated as XePtF6. Pursuant to his discovery, numerous xenon and krypton compounds were synthesized in macroscopic quantities. Among the noble‐gas elements, xenon has the most extensive chemistry, and it can possess formal oxidation states of 0, +2, +4, +6, and +8 in its compounds by forming fluorides, oxides, and oxide fluorides, as well as derivatives in which xenon is bonded to polyatomic groups through oxygen, nitrogen, and carbon. In addition, compounds containing Xe–Au, Xe–Xe, Xe–Cl, and Hg–Xe bonds are known. Other xenon‐element bonds are known in the gas phase or in low‐temperature matrices, which are exemplified by Xe–H, Xe–Si, Xe–S, Xe–X (X=Cl, Br, I), and Xe–U bonds. Krypton chemistry is more limited. Only compounds with krypton in the +2 oxidation state are known, namely, KrF2, salts of the KrF+and Kr2F3+cations, by analogy with xenon, the Kr–O bonded compound, Kr(OTeF5)2, and several species containing Kr–N bonds. Several gas‐phase and matrix‐isolated species in which krypton is bonded to carbon, hydrogen, and halides other than fluorine are also known. Radon is believed to form RnF2and RnF+by analogy with krypton and xenon. The only argon species that are known are the ArF+cation, which has been observed in the gas phase, and HArF, which has been stabilized in a low‐temperature argon matrix. To date, no argon, neon, or helium compounds have been isolated in macroscopic amounts. Noble‐gas compounds have been used as oxidizers and as oxidative fluorinating agents in chemical syntheses.