Keywords: 13sigmatropic.png I release this to the world as a PD image en wikipedia T vanschaik CommonsHelper 2005-11-25 Takometer wikipedia en Takometer original upload log page en wikipedia 13sigmatropic png 2005-11-25 23 25 Takometer 584×210× 10449 bytes <nowiki>I release this to the world as a PD image </nowiki> Reaction mechanisms Sigmatropic rearrangements |