# How to reduce the spacing in chemical symbols?

Currently, if want to write a chemical symbol, for example, ${}^{239}Np$, this is what I type in: {}^{239}Np. The result:

But it looks bad, I feel as if the "N" and "p" should be closer, or a different font should have been used.

How could I make better looking chemical symbols? Currently I am using mainly the MathJax of the SE, but sometimes I use other TeX as well.

• I don't know why my text code weren't processed as on other SE sites, maybe it is a localhost problem. I extended the question with a screenshot - if the mathjax works correctly by you, feel free to remove it. – peterh Jun 19 '16 at 2:40
• A warm welcome to TeX.SE! I think that a little more of an example might help. For instance the packages you load, and the fonts you load could have an effect on your spacing. Take a look at the guidelines set out for MWE's on this site for how much example to include in your example. What makes a good MWE meta.tex.stackexchange.com/q/3343/90087 – A Feldman Jun 19 '16 at 2:59
• @peterh see meta.tex.stackexchange.com/questions/1272/… – clemens Jun 19 '16 at 9:50

Obviously Np should be upright. Hence

\documentclass{article}
\usepackage{tensor}
\begin{document}

$^{239}\mathrm{Np}$

With tensor package:

$\tensor[^{239}]{\mathrm{Np}}{}$

But with both numbers not

$\tensor[^{239}_{93}]{\mathrm{Np}}{}$

but

$\tensor*[^{239}_{93}]{\mathrm{Np}}{}$

\end{document}


If by “other TeX” you mean LaTeX then use a dedicated chemistry package:

\documentclass{article}
\usepackage{chemformula}
\begin{document}

\ch{^{239}Np} \\
\ch{^{239}_{93}Np} % or \ch{^{239}93Np}

\end{document}


or

\documentclass{article}
\usepackage[version=4]{mhchem}
\begin{document}

\ce{^{239}Np} \\
\ce{^{239}_{93}Np}

\end{document}


or

\documentclass{article}

\usepackage{chemmacros}
\chemsetup{
formula = chemformula , % or mhchem'
modules = {isotopes}
}

\begin{document}

\isotope*{Np} \\
\isotope{Np}

\end{document}


All three examples give

You could throw in a negative kern and that would close up some of the space.

\documentclass[10pt,letterpaper]{article}

\begin{document}
${}^{239}N\kern -1pt p$
\end{document}


You could also use the elements package:

\documentclass[10pt,letterpaper]{article}
\usepackage{elements}
\begin{document}

$^{239}$\elementsymbol{Neptunium}

The electron distribution

of Neptunium is:

\elconf{Np}

\end{document}


• Element symbols should be typeset upright according to IUPAC recommendations – clemens Jun 19 '16 at 10:23
• Additional information: the chemmacros module isotopes that I've used in my answer uses the elements` package behind the scenes :) – clemens Jun 20 '16 at 12:46
• The "man behind the mask" ... – A Feldman Jun 20 '16 at 22:10