- Sodium nitrite (Wikipedia)
Sodium nitrite is an inorganic compound with the chemical formula NaNO2. It is a white to slightly yellowish crystalline powder that is very soluble in water and is hygroscopic. From an industrial perspective, it is the most important nitrite salt. It is a precursor to a variety of organic compounds, such as pharmaceuticals, dyes, and pesticides, but it is probably best known as a food additive used in processed meats and (in some countries) in fish products.
- Schläfli symbol (Wikipedia)
In geometry, the Schläfli symbol is a notation of the form {p,q,r,…} that defines regular polytopes and tessellations.