Fluorenol is an alcohol derivative of fluorene. This in part due to the shape of fluorene. Cicloprofen is a NSAID 2-arylpropionic acid made from fluorene. Yamamoto and Grignard coupling reactions have been applied to polymerization of fluorene derivatives. Fluorene is a precursor to other fluorene compounds; the parent species has few applications. Other PAC compounds appearing as minerals include fluorene as kratochvilite; and anthracene as ravatite. CataCXium F sulf is a water-soluble organophosphorus compound derived from fluorene. Fluorene and its derivatives can be deprotonated to give ligands akin to cyclopentadienide. Oxidation of fluorene gives fluorenone, which is nitrated to give commercially useful derivatives. However, more promising was integrating the optoelectronic properties of fluorene into a polymer. Sodium dichromate can be used in fluorene to fluorenone conversion. For example, 9,9-fluorenyldipotassium can be obtained by treating fluorene with potassium metal in boiling dioxane. This basic fluorene backbone strengthens the molecule on account of the carbon rings. As interest in conducting plastics grew, fluorene again found application.