Amine oxide Amine oxide An amine oxide, also known as amine-"N"-oxide and "N"-oxide, is a chemical compound that contains the functional group RN−O, an N−O coordinate covalent bond with three additional hydrogen and/or hydrocarbon side chains attached to N. Sometimes it is written as RN→O or, wrongly, as RN=O. In the strict sense, the term "amine oxide" applies only to oxides of tertiary amines. Sometimes it is also used for the analogous derivatives of primary and secondary amines. Examples of amine oxides include pyridine-"N"-oxide, a water-soluble crystalline solid with melting point 62–67 °C, and "N"-methylmorpholine "N"-oxide, which is an oxidant. Amine oxides
U Should've Known Better backbeat, the song's instrumentation consists of screeching guitars and an understated harp pattern. Lyrically, Monica, as the protagonist, delivers a message of loyalty to her imprisoned love interest and sings about staying down for him despite his doubts. The song was generally well received by contemporary music critics who highlighted the heartfelt emotion and sadness. Released as the fourth and final single from "After the Storm" in May 2004, the single marked Monica's first balladic release in over five years. On the charts, "U Should've Known Better" peaked at number 19 on the US "Billboard" Hot 100 and number 6