page_title: Crystallographic defects in diamond
section_title: Nitrogen
hierarchical_section_title: Crystallographic defects in diamond / Extrinsic defects / Nitrogen
caption_attribution_description: English: C center in diamond
context_page_description: Imperfections in the crystal lattice of diamond are common. Such crystallographic defects in diamond may be the result of lattice irregularities or extrinsic substitutional or interstitial impurities, introduced during or after the diamond growth. The defects affect the material properties of diamond and determine to which type a diamond is assigned; the most dramatic effects are on the diamond color and electrical conductivity, as explained by the electronic band structure.
  The defects can be detected by different types of spectroscopy, including electron paramagnetic resonance, luminescence induced by light or electron beam, and absorption of light in the infrared, visible and UV parts of the spectrum. The absorption spectrum is used not only to identify the defects, but also to estimate their concentration; it can also distinguish natural from synthetic or enhanced diamonds.
context_section_description: The most common impurity in diamond is nitrogen, which can comprise up to 1% of a diamond by mass. Previously, all lattice defects in diamond were thought to be the result of structural anomalies; later research revealed nitrogen to be present in most diamonds and in many different configurations. Most nitrogen enters the diamond lattice as a single atom (i.e. nitrogen-containing molecules dissociate before incorporation), however, molecular nitrogen incorporates into diamond as well.
  Absorption of light and other material properties of diamond are highly dependent upon nitrogen content and aggregation state. Although all aggregate configurations cause absorption in the infrared, diamonds containing aggregated nitrogen are usually colorless, i.e. have little absorption in the visible spectrum. The four main nitrogen forms are as follows:
caption: Schematic of the C center
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