antineutroneille
Antineutronium, often referred to as antineutronium or antineutronium atoms, is a theoretical form of antimatter consisting of an antineutron orbited by an antiproton, analogous to how a normal atom consists of a neutron orbited by a proton. More commonly, the term refers to a system comprising an antineutron and an antiproton. However, antineutronium itself is distinct from antihydrogen, which consists of an antiproton orbited by a positron.
The antineutron is the antiparticle of the neutron, differing in its baryon number and quark composition. While
The existence of antineutronium atoms is purely hypothetical as they have not been observed. Theoretical models