Ylides of this element are important intermediates in the Corey-Chaykovsky reaction. This element forms cluster cofactors with iron in enzymes such as aconitase and ferredoxin. It catenates into its monoclinic form at high temperatures, and it is stable in its cyclic rhombic form at room temperature. Cystine residues in proteins form a bond that is named for a dimer of this element and thiols are organic compounds containing this heteroatom. The binary compound formed from reaction of hydrogen with this element has a repulsive odor and is released by rotting eggs. For 
Ylides of this element are important intermediates in the Corey-Chaykovsky reaction. This element forms cluster cofactors with iron in enzymes such as aconitase and ferredoxin. It catenates into its monoclinic form at high temperatures, and it is stable in its cyclic rhombic form at room temperature. Cystine residues in proteins form a bond that is named for a dimer of this element and thiols are organic compounds containing this heteroatom. The binary compound formed from reaction of hydrogen with this element has a repulsive odor and is released by rotting eggs. For 10 points, name this chalcogen that is below oxygen on the periodic table and has the atomic symbol S.
Ylides of this element are important intermediates in the Corey-Chaykovsky reaction.
sulfur