The intensity of doubly charged ions are normally relatively small in electron ionization (EI) mass spectra, but often noted in electrospray spectra. However, we noted one that was almost the base peak in a phosphate spectrum and have included many others noted in the NIST library collection! The same type of doubly charged ion is almost nonexistent in the EI spectrum of the corresponding phosphite.
Link to Our Doubly Charge Phosphate Example
Here are some other examples:
Others_noted in My Work
National Bureau of Standards 1949 Paper