Silicon29

Silicon-29 is a stable isotope of the element silicon, which has an atomic number of 14 and a mass number of 29. In nature, it accounts for about 4.7% of silicon, with the majority being 28Si (~92%) and a smaller portion of 30Si (~3%). Unlike 28Si, 29Si contains a nonzero nuclear spin and is therefore observable by nuclear magnetic resonance (NMR) techniques. Its presence is important in fields ranging from chemistry to materials science.

Nuclear properties of 29Si include a spin of 1/2 and a corresponding magnetic moment. The gyromagnetic ratio is about γ/2π ≈ -8.465 MHz per tesla, which defines its resonance frequency in a magnetic field. Because 29Si has a relatively small natural abundance, signals from natural silicon are weaker than those from more abundant nuclei; experiments often use isotopically enriched 29Si to improve sensitivity and signal-to-noise.

Applications and use in research involve 29Si NMR spectroscopy to probe silicon-containing compounds, networks of silicon-oxygen bonds, and surface chemistry in materials. The isotope’s spin-1/2 nature yields sharp resonances without quadrupolar broadening, making it a useful probe in solid-state and solution-state studies. In addition, isotopically enriched 29Si is employed in advanced research areas, including quantum computing and materials engineering, where the interaction of silicon-29 nuclei with other spins in silicon-based devices is of interest.

Availability and safety: 29Si is a stable, non-radioactive isotope of silicon. It is commercially available in isotopically enriched form for research purposes and poses no special safety concerns beyond standard laboratory handling of silicon compounds.