diff --git a/Preamble/Main.tex b/Preamble/Main.tex
index b6f3954..663aa9b 100755
--- a/Preamble/Main.tex
+++ b/Preamble/Main.tex
@@ -365,7 +365,6 @@
 \newcommand{\ubspacel}[2]{% Correct \underbrace spacing
   \mathrlap{\underbracket[0pt][0pt]{\phantom{#1\strut}}_{\text{#2}}}\underbracket[0.5pt][0pt]{#1}}
 
-\usepackage[version=3]{mhchem} % use: \ce
 %\usepackage{eurosym}	% fuer das Eurosymbol
 %\DeclareUnicodeCharacter{20AC}{\euro{}}
 
diff --git a/Preamble/Page.tex b/Preamble/Page.tex
index 8c80555..48e601c 100755
--- a/Preamble/Page.tex
+++ b/Preamble/Page.tex
@@ -67,6 +67,7 @@
 \usepackage{soulutf8}   % hyphenatable letterspacing, underlining and some derivatives such as overstriking and highlighting, soul
 \usepackage{blindtext}	% Damit ich mir nicht immer neuen Text ausdenken muss
 
+\usepackage[version=3]{mhchem} % use: \ce   IMPORTANT: mhchem must be load before xparse and/or xpatch: l3str: \c_backslash_str
 \usepackage{xparse}
 
 % Befehle: