# 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?

## closed as off-topic by Todd Minehardt, aventurin, airhuff, Tyberius, M.A.R.Apr 23 '18 at 20:15

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• 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.

It may work if you manage to shoot both neutrons into different hydrogen atoms in such a manner that both hydrogens are displaced towards the other. But this type of collision can be considered more of a thought experiment than anything practical. (Even just hitting a single molecule with two neutrons at the same time is hard enough.)

The process is nuclear fusion which takes place in sun where H is combined to form high energy and He is produce which produce light too.You can do it but at rare instance when neutron is bombarded it may form neutron when protons and electron like in neutron star for more detail

https://youtu.be/Cb8NX3HiS4U