Formula unit Formula unit A formula unit in chemistry is the empirical formula of any ionic or covalent network solid compound used as an independent entity for stoichiometric calculations. It is the lowest whole number ratio of ions represented in an ionic compound. Examples include ionic NaCl and KO and covalent networks such as SiO and C (as diamond or graphite). Ionic compounds do not exist as individual molecules; a formula unit thus indicates the lowest reduced ratio of ions in the compound. A "chemical formula" shows the kinds and numbers of atoms in the smallest representative unit of a substance. In
Compound (fortification) Compound (fortification) In military science, a compound is a type of fortification made up of walls or fences surrounding several buildings in the center of a large piece of land. The walls can either serve the purpose of being tall, thick, and impenetrable, in which case they would be made of wood, stone, or some other like substance; or dangerous to attempt to scale, in which case they could be made of barbed wire or electrified. Compounds can be designed to double as living spaces and military structures in the middle of hostile territory or as a military area within