If an induced magnetic field is generated in the same direction as the external magnetic field due to the effect of the electron circulation, so that there is absorption at the low field of the nuclear magnetic resonance spectrum, the absorption peak on the nuclear magnetic resonance spectrum that appears at the low field strength is called de shielding. For example, due to the electron circulation of double bond electrons with doubtful groups, the protons in a CIID group of aldehydes are typical of the deshielded atoms. [1]
