Soldering terminology

Among other things, the MIL standard is used for specifying the composition of fluxes. The equivalent is the amount X in grams of any element that reacts with 7.999 g of oxygen (equivalent to ½ mole of oxygen). This amount X is known as 1 equivalent ( eq) of the given element. For elements which do not react directly with oxygen, the equivalent may be determined indirectly through an intermediate reactant. The equivalent is the ratio of the atomic mass of the element and its valence. See also Gram equivalent .