Dirac equation for the electron implied that the Electron should have spin 1/2, and a magnetic moment of eh/(4πm), where h is the Planck constant and m is the electron mass, correct to the accuracy of 0.1%.

The equation predicted the existence of antiparticles, such as the positron and the negatively charged anti–proton, objects now well known in high–energy physics laboratories. Indeed, all particles have corresponding antiparticles and almost all of them are now known empirically. The positron and antiproton are particularly well known, both being stable in a vacuum, and are now widely used in collider accelerators, with which physicists study physical phenomena at very high energies.

The equation demands the existence of antiparticles and actually predated their experimental discovery. This made the discovery of the positron, the antiparticle of the electron, one of the greatest triumphs of modern theoretical physics.