# Could you make a helium atom from hydrogen gas? [closed]

Hydrogen gas is $\ce{H2}$, and contains 2 electrons and 2 protons. My question is, with sufficient pressure, could you fire two neutrons at the molecule and have them form a single Helium atom?

• The sun does this all the time. It is hard to convert H2 gas to helium. That is the gist of fusion reactors which my someday be a power source here on earth. – MaxW Oct 6 '17 at 18:51
• chemistry.stackexchange.com/questions/82648/… – Mithoron Oct 6 '17 at 18:52
• Not really H2 @MaxW. Not even atomic hydrogen. Hot enough to have unadulterated protons in the soup. – Oscar Lanzi Oct 8 '17 at 18:31
• I'm voting to close this question as off-topic because its about physics, not chemistry – Tyberius Apr 23 '18 at 3:01

The hydrogen nuclei are spaced out by about $\pu{70pm}$, if I guessed/remembered the number correctly. To generate a helium nucleus, this distance has to be reduced to almost $\pu{0pm}$ against the repulsion of like charges. So if you just bombarded a hydrogen molecule with neutrons from one side, nothing would happen since the two would not fuse.