Charge-transfer complex
![Fig. 1 I2•PPh3 charge-transfer complexes in CH2Cl2. From left to right: (1) I2 dissolved in dichloromethane - no CT complex. (2) A few seconds after excess PPh3 was added - CT complex is forming. (3) One minute later after excess PPh3 was added, the CT complex [Ph3PI]+I− has been formed. (4) Immediately after excess I2 was added, which contains [Ph3PI]+[I3]−.[7]](/uploads/202501/04/Iodine-triphenylphosphine_charge-transfer_complex_in_dichloromethane0224.jpg)

A charge-transfer complex (CT complex) or electron-donor-acceptor complex is an association of two or more molecules, or of different parts of one large molecule, in which a fraction of electronic charge is transferred between the molecular entities. The resulting electrostatic attraction provides a stabilizing force for the molecular complex. The source molecule from which the charge is transferred is called the electron donor and the receiving species is called the electron acceptor.