Problem bei der Verwendung von chemmacros

\documentclass[12pt,ngerman,smallheadings,pointlessnumbers]{scrreprt} 
\usepackage{ae}
\usepackage{setspace} 
\usepackage[hyphens]{url}
\usepackage[paper=a4paper,left=30mm,right=25mm,top=40mm,bottom=25mm, headheight=40pt]{geometry}
\usepackage[latin1]{inputenc} 
\usepackage{babel}
\usepackage[T1]{fontenc} 
\usepackage[headsepline, automark,footsepline,plainfootsepline]{scrpage2} 
\usepackage{chemfig}
\newcommand\setpolymerdelim[2]{\def\delimleft{#1}\def\delimright{#2}}
\def\makebraces[#1,#2]#3#4#5{%
    \edef\delimhalfdim{\the\dimexpr(#1+#2)/2}%
    \edef\delimvshift{\the\dimexpr(#1-#2)/2}%
    \chemmove{%
        \node[at=(#4),yshift=(\delimvshift)]
        {$\left\delimleft\vrule height\delimhalfdim depth\delimhalfdim
            width0pt\right.$};%
        \node[at=(#5),yshift=(\delimvshift)]
        {$\left.\vrule height\delimhalfdim depth\delimhalfdim
            width0pt\right\delimright_{\rlap{$\scriptstyle#3$}}$};}}
\setpolymerdelim[]

\newcommand{\pol}[1]{\rlap{${}^{^{\color{red} \delta #1}}$}}
\newcommand{\ind}[0]{\text{ }}
\usepackage{chemmacros}
\definesubmol{nitro}{
  -\chemabove{N}{\fscrp}
    (=[1]\lewis{20,O})
    (-[7]\chemabove{\lewis{206,O}}{\hskip1.5em\fscrm})
}

\tikzset{
  elmove/.style={red,-el,shorten >=3pt, shorten <=3pt}
}
\usepackage{xstring}
\usepackage{chemstyle}
\usepackage[version=4, arrows=pgf-filled]{mhchem}
\usepackage{mathtools}
\usepackage{fixmath}
\usepackage{amsmath}
\usepackage{siunitx}
\usepackage{tikz} % To generate the plot from csv
\usetikzlibrary{positioning}
\usetikzlibrary{tikzmark}
\usepackage{tkz-euclide}% lädt tikz und damit auch xcolor 
\colorlet{lightgray}{black!10} 
\colorlet{pencil}{black!25}   
\usetkzobj{all} 
\usepackage{tikzorbital}

\begin{document}

\minisec{Aktivierung der Salpetersäure durch die Schwefelsäure}
\vspace{2\baselineskip}
\begin{center}
  \schemestart
    \chemfig{H@{O}\lewis{26,O}!{nitro}}
    \+
    \chemfig{@{H}H-[@{b1}]@{O1}OSO_3H}
    \arrow(.base east--.base west){<=>[][][3.5pt]}
    \chemfig{H|\chemabove{\Lewis{2,O}}{\fscrp}(-[6,,2]H)!{nitro}}
    \+
    \chemfig{HSO_4^{\fminus}}
  \schemestop
  \chemmove[elmove]{
    \draw (O).. controls +(north:2cm) and +(105:2.5cm).. (H);
    \draw (b1).. controls +(north:1cm) and +(105:1cm).. (O1);
  }
\end{center}

\minisec{Bildung des Nitronium-Ions}
\bigskip
\begin{center}
  \schemestart
    \chemfig{
      H|@{O}\chemabove{\Lewis{2,O}}{\fscrp}(-[6,,2]H)
      -[@{b1}]\chemabove{N}{\fscrp}
        (=[1]\lewis{20,O})
        (-[@{b2}:315,,,,]@{O2}\chemabove{\lewis{206,O}}{\hskip1.5em\fscrm})
    }
    \arrow(.base east--.base west){->[][][3.5pt]}
    \chemfig{H_2O}
    \+
    \chemfig{\lewis{26,O}=\chemabove{N}{\fscrp}=\lewis{26,O}}
  \schemestop
  \chemmove[elmove]{
    \draw[shorten >=10pt](b1).. controls +(90:1cm) and +(90:1cm).. (O);;
    \draw (O2).. controls +(90:7mm) and +(45:5mm).. (b2);
  }
\end{center}

\end{document}