Any of a group of chemical analysis methods that depend on measurement of the wavelength and intensity of electromagnetic radiation. It is used chiefly to determine the arrangement of atoms and electrons in molecules on the basis of the amounts of energy absorbed during changes in their structure or motion. In more common usage, it usually refers to ultraviolet (UV) and visible emission spectroscopy or to UV, visible, and infrared (IR) absorption spectrophotometry.
Learn more about spectrochemical analysis with a free trial on Britannica.com.
A partial spectrochemical series listing of ligands from small Δ to large Δ:
I− < Br− < S2− < SCN− < Cl− < NO3− < N3− < F− < OH− < C2O42− ≈ H2O < NCS− < CH3CN < py (pyridine) < NH3 < en (ethylenediamine) < bipy (2,2'-bipyridine) < phen (1,10-phenanthroline) < NO2− < PPh3 < CN− ≈ CO
(for a table, see the ligand page)