28Si29Si

28Si29Si refers to a molecular species composed of one atom of silicon-28 and one atom of silicon-29. Silicon isotopes are distinguished by the number of neutrons in their nucleus. Silicon has three stable isotopes: silicon-28 (28Si), silicon-29 (29Si), and silicon-30 (30Si). Silicon-28 is by far the most abundant, making up approximately 92.2% of natural silicon. Silicon-29 accounts for about 4.7%, and silicon-30 constitutes around 3.1%.

The molecule 28Si29Si would therefore be a heteronuclear diatomic molecule of silicon. Such molecules are typically formed under specific conditions, such as in high-temperature environments or through advanced synthetic techniques. In astrophysical contexts, diatomic silicon molecules, including isotopic variations, can exist in stellar atmospheres and circumstellar envelopes where silicon is present. The spectroscopic properties of 28Si29Si would be distinct from homonuclear diatomic silicon molecules like 28Si2 or 29Si2 due to the differing nuclear spins and masses of the two isotopes. Studying such isotopically mixed molecules can provide valuable insights into isotopic fractionation processes and the chemical conditions present in various environments.