Positronium

Positronium is a bound state of a positron and an electron, with a lifetime of 0.14 ns.
It is predicted by quantum electrodynamics and can be increased by non-standard neutrino properties.
The energy levels of positronium are roughly half of what they are for the hydrogen atom.
Positronium can be formed and decays in materials after a radioactive atom undergoes a β+ decay.
The discovery of positronium was made by Martin Deutsch at MIT in 1951.
The ortho-positronium lifetime puzzle was resolved with further calculations and measurements.
Positronium can form exotic compounds, such as molecules of positronium hydride and cyanide.
The naturally occurring positrons in the present day result from high-energy interactions and are too hot to form electrical bonds before annihilation.

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Позитроний