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
Chemical state Such a compound or salt is described as an ionic compound with ionic bonds which means that, in effect, all of the electron density of one or more valence electrons has been transferred from the less electronegative group of elements to the more electronegative group of elements. In the case of a non-ionic compound the chemical bonds are non-ionic such meaning the compound will probably not dissolve in water or another polar solvent. Many non-ionic compounds have chemical bonds that share the electron density that binds them together. This type of chemical bond is either a non-polar covalent bond or