Frankland, Sir Edward (1825-1899), was an English chemist whose research covered a wide field. With the Scottish chemist Alexander Crum Brown, Frankland worked on structural formulas. A structural formula is a chemical formula that shows how the atoms in a molecule are arranged. With the German chemist Hermann Kolbe, he worked on the theory of valence. The valence of a chemical element is a number that indicates the element's ability to combine with other elements (see Valence).