The core of CIL's business is the separation of stable isotopes and the synthesis and marketing of organic and biochemical compounds that are specifically and highly enriched with stable isotopes such as Carbon-13 (13C), Deuterium (D), Nitrogen-15 (15N), Oxygen-18 (18O) and Oxygen-17 (17O). Isotopes are forms of a particular element that vary slightly from one another in atomic weight. Isotopically labeled materials can be detected, measured, and monitored by methods such as Mass Spectrometry (Mass Spec) and Nuclear Magnetic Resonance (NMR). CIL's 15,000 products contribute to advancements in such diverse fields as physics, chemistry, biomedical, analytical, and diagnostic research, as well as environmental testing.