Soldering terminology

A type of activator material for fluxing agents, used, among others, in solder paste, in which a polydentate ligand forms a coordinative bond. Since, as illustrated below, this ligand is similar to a jaw surrounding a central atom or group (for example NH ₂ (CH ₂ )2NH ₂ or O(CO) ₂ O), such complexes are called chelates after the Greek Χηλη ( chele), meaning “ crab claw”.

Such chelating agents can be used as precipitation agents (dimethyl-glyoxime, oxine and acetylacetone) or as soldering flux additives, cleaning agents, stabilizers or masking agents for better isolation and purification of metal salts. When the multidentate ligand binds to a metal ion, the resulting compound is more stable than the compound containing an ordinary ligand. This is called the chelate effect.