An excited state of this element named for Hoyle is important in stellar nucleosynthesis. One moleculecreated from this element isomerises to create Stone-Wales defects, and that form is purified using amixture of DBU and trimethylbenzene. One form of this element is produced when cosmic rays bombardnitrogen. Chemical shifts between 0 and 200 ppm are observed in a type of NMR that observes a form ofthis element. Kroto, Smalley, and Curl found an 
An excited state of this element named for Hoyle is important in stellar nucleosynthesis. One moleculecreated from this element isomerises to create Stone-Wales defects, and that form is purified using amixture of DBU and trimethylbenzene. One form of this element is produced when cosmic rays bombardnitrogen. Chemical shifts between 0 and 200 ppm are observed in a type of NMR that observes a form ofthis element. Kroto, Smalley, and Curl found an unusual form of this element which forms a ball-likestructure. A sample of one type of this element is used in the precise definition of Avogadro's number,while another form of this element has a half-life of 5700 years. For 10 points, name this element whoseisotope with a mass number of 14 is used in radioactive dating.
An excited state of this element named for Hoyle is important in stellar nucleosynthesis.
carbon