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
Corrosive substance Corrosive substance A corrosive substance is one that will damage or destroy other substances with which it comes into contact by means of a chemical reaction. The word "corrosive" is derived from the Latin verb "corrodere", which means "to gnaw", indicating how these substances seem to "gnaw" their way through flesh or other materials. The word corrosive refers to any chemical that will dissolve the structure of an object. They can be acids, oxidizers, or bases. When they come in contact with a surface, the surface deteriorates. The deterioration can happen in minutes, e.g. concentrated muriatic acid spilled on skin;