# Why are the arrows in the chemical equation not full arrows?

I have the following code:

$$\ce e^- + ^{40}_{19}K -> ^{40}_{18}Ar^* + \Pgne -> ^{40}_{18}Ar + \Pgne + \gamma$$


but in my document -> is not connected for a full arrow.

I have:

\usepackage[version=4]{mhchem}

\usepackage[italic]{hepnames}


in my document.

So i'm wondering what is wrong.

I have tried adding {} around the equation ( { is before e^- and } is after \gamma) but it looks like this: which is even worse.

• First of all, start with removing the empty lines in the equation environment. You should get an error message from this. Apr 25 '20 at 15:14

Remove the empty lines in the equation environment, place the whole chemical equation inside of the argument of \ce and surround \Pgne by a set of {}:

\documentclass{article}

\usepackage[version=4]{mhchem}
\usepackage[italic]{hepnames}

\begin{document}

$$\ce {e^- + ^{40}_{19}K -> ^{40}_{18}Ar^* + {\Pgne} -> ^{40}_{18}Ar + {\Pgne} + \gamma}$$
\end{document}

• Added {} like you said and that fixed it, thanks! Apr 25 '20 at 15:20
• @MarcusJohnson that is the documented escape mechanism for input mhchem doesn't know what to do with Apr 25 '20 at 15:35