[Tex/LaTex] The lightning symbol in an equation environment

symbols

I tried to use the lightning symbol but when I use it together with equations it becomes an ''E'' Why is that? 

\documentclass[11pt,a4paper,oneside]{report} 
\usepackage[pdftex]{graphicx} 
\usepackage[T1]{fontenc} 
\usepackage{fouriernc}
\usepackage{mathtools}
\usepackage{amsfonts,amsmath,amssymb,amsthm} 
\usepackage[a4paper, hmargin={3.5cm,3cm}, vmargin={2.5cm,2.5cm}]{geometry} %margin
\usepackage{multicol}
\usepackage{enumerate}
\usepackage{ marvosym }


\begin{document}
\Lightning
but when used in an equation environment it becomes ''E''
\begin{equation}
\Lambda\gamma \Lightning
\end{equation}
\end{document}

the output
enter image description here

What can be done to use \Lightning in equations? Thank you

Best Answer

To instruct LaTeX to treat \Lightning as a text-mode rather than as a math-mode macro, you could type either

\mbox{\Lightning}

or (since you're already loading the amsmath package)

\text{\Lightning}

for all math-mode occurrences of this macro.

Addendum: As @egreg has pointed out in a comment, a key issue (bug?) is that the file marvosym.sty provides the instruction 

\newcommand{\mvchr}[1]{{\mvs\char#1}}

This macro assumes (implicitly) that the symbols of the marvosym package will only ever be used in text mode. By redefining this macro via

\renewcommand{\mvchr}[1]{\mbox{\mvs\symbol{#1}}}

in the preamble (after loading the marvosym package, of course), the behavior of this macro is modified globally and it's no longer necessary to encase any of the many individual macros of the marvosym package in \mbox wrappers.

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