# protonium

> bound state of a proton and antiprotron

**Wikidata**: [Q936991](https://www.wikidata.org/wiki/Q936991)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/Protonium)  
**Source**: https://4ort.xyz/entity/protonium


## References

1. Freebase Data Dumps. 2013
2. BabelNet