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Carbyne and chaoite are also considered as allotropic forms of carbon. The chemical structure is an alternating triple bond between the carbon atoms (—C≡C—). The carbon atom is thus in the sp‐hydride state. The estimated bonding lengths in this linear molecule are 0.138 nm for the single bond and 0.121 nm for the triple bond. Young’s modulus of this substance should be 40 times that of diamond. This molecule is not easy to synthesize with chain lengths more than eight acetylenic units. It was claimed that this acetylenic carbon was found in shock‐metamorphosed graphite gneiss in the Nördlinger Ries crater in Germany, later named chaoite [18]. Its existence in various meteorites has been reported also. To summarize, carbynes have no industrial importance and have been subject of academic curiosity.