Classes of metals products with soft bases, which are bases with covalent bonds. The IUPAC Gold Book provides a more general definition of a class (a) metal ion, as "A metal ion that combines preferentially with ligands containing ligating atoms that are the lightest of their Periodic Group", and a class (b) metal as one that combines preferentially with ligands containing ligating atoms other than the lightest of their Periodic Group. Classes of metals Class A metals are metals that form hard acids. Hard acids are acids with relatively ionic bonds. These metals, such as iron, aluminium, titanium, sodium, calcium and the lanthanides,
Institute of Cast Metals Engineers Institute of Cast Metals Engineers The Institute of Cast Metals Engineers (ICME), originally the British Foundrymen's Association is a British professional engineering institution founded in 1904. It publishes the Foundry Trade Journal, which was established in 1902. It was founded as the British Foundrymen's Association in 1904. It was given a Royal Charter on 25 November 1921. On 11 October 2000, it changed its name to the Institute of Cast Metals Engineers. It is licensed by the Engineering Council to assess candidates for inclusion on its Register of professional Engineers and Technicians. The Institute's address is ICME Metalforming Centre, 47