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,
Metals Service Center Institute Metals Service Center Institute The Metals Service Center Institute (MSCI) is a trade association and nonprofit organization based in Rolling Meadows, Illinois, in the United States. It was established as the American Horseshoe and Heavy Hardware Association in 1909 and was subsequently known as the American Steel Warehouse Association, then the Steel Service Center Institute. The organization's members are primarily metal service centers that inventory and distribute metals for industrial customers and perform first-stage processing. MSCI has approximately 400 members operating from 1,500 locations primarily in North America. MSCI members purchase about 75 million tons of steel, aluminum and other