Silicon Chemistry in the Interstellar Medium and Circumstellar Envelopes

The molecules comprising the main group elements in lower valency are identified in the interstellar medium. Silicon is the fifth most abundant trace element, associated with late-type stars and regions where stars are developing, and plays a crucial role in forming interstellar dust grains. In the recent past, integrated experimental and computational strategies in silicon chemistry have become increasingly popular, and researchers have identified several Si-bearing molecules in the interstellar medium and circumstellar envelopes. About 300 molecules are observed in the interstellar medium and circumstellar envelopes in total, of which 15 are Si-bearing molecules. In addition, 28 Si-bearing chains and rings are reported as potential candidates for astronomical detection. This review summarizes the available data on the astronomical aspects of Si-bearing molecules. Detailed investigation of Si-bearing molecules commonly found in star-forming areas, late-type stars, and their relevance in space have been well documented here. Finally, attention is drawn to potential Si-bearing molecules for future interstellar identification, which has been reported using experimental and quantum chemical approaches.