Definition: In this task you will be given a text passage from a trivia quiz. You should choose the category this question belongs to from these categories: History, Science, Social Science, Fine Arts, Literature. You can only choose one category, so if in doubt, please choose the closest match.
Input: A compound consisting of oxygen, chlorine, and this element reacts with DMF to produce the formylating agent used in the Vilsmeier reaction. It is the central atom in a phenyl-containing compound that is oxidized in both the Mitsunobu Esterification and the reduction of azides to amines in the Staudinger Reaction. This element can form double bonds through p-pi/d-pi bonding, which can alternately be depicted as adjacent positive and negative charges. Such a double bond between this element and carbon is found in a reagent that reacts with carbonyl groups to give alkenes in the Wittig reaction. FTP, identify this element that forms ylides and in the backbone of nucleic acids with atomic symbol P.
Output:
Science