Soldering terminology

A group within a molecule that forms compounds with water with difficulty. Copper-alkyl (CuH _2n+1), phenyl (C ₆ H ₅) and other hydrocarbon groups fall into this category. Due to the low reactivity with water molecules, such connections are used for NoClean fluxing agents where residues need not be removed. Groups that readily combine with water are referred to as hydrophilic radicals. See also Hydrophilic radical.