Just noticed that adding \scriptstyle{\oplus} or \scriptsize{\oplus} doesn't actually change anything. I'm not sure if I have been using the command wrong (I'm trying to decrease the size of the \oplus), since I've included it in a lot of my other mechanisms. Thanks in advance for any suggestions on this.
Edit: Clarified the effect I expected to see Edit 2: Changed incorrect charge on N from - to +
\documentclass{article}
\usepackage{graphicx}
\usepackage{chemfig}
\usepackage{geometry}
\usepackage{tabu}
\usepackage[utf8]{inputenc}
\usepackage{tikz}
\usepackage{siunitx}
\usepackage{chemmacros}
\usetikzlibrary{arrows}
\title{}
\author{}
\date{}
\begin{document}
\maketitle
\chemfig{-[:30]-[:-30]N^{\scriptstyle{\oplus}}H_3}
\chemfig{-[:30]-[:-30]N^{\scriptsize{\oplus}}H_3}
\chemfig{-[:30]-[:-30]N^{\oplus}H_3}
\end{document}
\scriptstyle
nor\scriptsize
take an argument so the following{..}
are wrong. Superscripts are already in\scriptstyle
so that would not be expected to do anything in a superscript, size commands like\scriptsize
are not allowed in math mode. You have not said what effect you expected to see?LaTeX Font Warning: Command \scriptsize invalid in math mode on input line 21.
\scriptstyle
selects the math style used in superscripts, If it reduced the size of a delta it was presumably not in a superscript. but\scriptstyle{\delta} abc
makes all of \delta a b and c superscript sized.