Molecular massThe molecular mass (m) is the mass of a given molecule, for which the unit dalton (Da) is used. Different molecules of the same compound may have different molecular masses because they contain different isotopes of an element. The related quantity relative molecular mass, as defined by IUPAC, is the ratio of the mass of a molecule to the atomic mass constant (which is equal to one dalton) and is unitless. The molecular mass and relative molecular mass are distinct from but related to the molar mass.
Coordination complexA coordination complex is a chemical compound consisting of a central atom or ion, which is usually metallic and is called the coordination centre, and a surrounding array of bound molecules or ions, that are in turn known as ligands or complexing agents. Many metal-containing compounds, especially those that include transition metals (elements like titanium that belong to the periodic table's d-block), are coordination complexes. Coordination complexes are so pervasive that their structures and reactions are described in many ways, sometimes confusingly.
Cooper (profession)A cooper is a person trained to make wooden casks, barrels, vats, buckets, tubs, troughs and other similar containers from timber staves that were usually heated or steamed to make them pliable. Journeymen coopers also traditionally made wooden implements, such as rakes and wooden-bladed shovels. In addition to wood, other materials, such as iron, were used in the manufacturing process. The trade is the origin of the surname Cooper. The word "cooper" is derived from Middle Dutch or Middle Low German kūper 'cooper' from kūpe 'cask', in turn from Latin cupa 'tun, barrel'.
