A simple diagram summarizing the standard potentials for an element in different oxidation states. The different species are written in a horizontal line in order of decreasing oxidation state, with the most highly oxidized species on the left. Arrows are written between adjacent species with the standard potential in volts indicated above the arrow. Often the oxidation number is included in the diagram. The standard electrode potential for nonadjacent species can be calculated, but values for common couples are often indicated by additional arrows, Latimer diagrams depend on pH and are commonly given for both acidic and alkaline conditions. The diagram was devised by Wendell Mitchell Latimer (1893–1955) in 1938. See also Frost diagram.