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Chapter 2 Molecules Detected in Interstellar Space

In this section, an overview is given of molecules detected in the interstellar medium and circumstellar envelopes. Given that so far more than 150 species have been observed in interstellar space, this overview can by no means be complete. Therefore, we focus on the detections of the first molecules and then give examples of prototypical molecules and recent new detections. This section is based on the Menten (2003) article presented in the proceedings of the 2003 Zermatt conference [1].