带有圆圈/符号和文字的平衡箭头

Question

我怎样才能写出带有圆圈和三角形符号的可逆箭头的化学方程式？

我尝试过调整化学公式结果很糟糕：

\usepackage{chemformula}
\NewChemArrow{<=O>}{
  \draw[chemarrow,-left cf]
    ([yshift=.3ex]cf_arrow_start) -- ([yshift=.3ex]cf_arrow_end) ;
  \draw[chemarrow,left cf-]
    ([yshift=-.3ex]cf_arrow_start) -- ([yshift=-.3ex]cf_arrow_end) ;
  \draw[chemarrow] (cf_arrow_mid) circle (.4ex) ;
}`

`\begin{equation}
\ch{CO}^{*} + \ch{O}^{*} \ch{->[ k1 ]} \ce{NO2}^{*} +\ce{O}^{*} \\
\end{equation}`

`\begin{equation}
\ch{CO}^{*} + \ch{O}^{*} \ch{<=o>[ K2 ]} \ch{NO2}^{*} \\
\end{equation}

Answer 1

\documentclass{article}
\usepackage{chemformula}
\def\mylen{0.6ex}
\NewChemArrow{<=0>}{
    \draw[chemarrow,-left cf]
        ([yshift=\mylen/3]cf_arrow_start) --
        ([yshift=\mylen/3]cf_arrow_end) ;
    \draw[chemarrow,left cf-]
        ([yshift=-\mylen/3]cf_arrow_start) --
        ([yshift=-\mylen/3]cf_arrow_end) ;
    \draw[chemarrow]
        (cf_arrow_mid) circle (\mylen) ;
}
\NewChemArrow{-l>}{
    \draw [chemarrow,-cf](cf_arrow_start)--(cf_arrow_end);
    \draw[chemarrow]
        ([shift={(-\mylen,-\mylen)}]cf_arrow_mid) --
        ([shift={(0,\mylen)}]cf_arrow_mid) --
        ([shift={(\mylen,-\mylen)}]cf_arrow_mid);
}
\NewChemArrow{<=l>}{
    \draw[chemarrow,-left cf]
        ([yshift=\mylen/3]cf_arrow_start) --
        ([yshift=\mylen/3]cf_arrow_end) ;
    \draw[chemarrow,left cf-]
        ([yshift=-\mylen/3]cf_arrow_start) --
        ([yshift=-\mylen/3]cf_arrow_end) ;
    \draw[chemarrow]
        ([shift={(-\mylen,-\mylen)}]cf_arrow_mid) --
        ([shift={(0,\mylen)}]cf_arrow_mid) --
        ([shift={(\mylen,-\mylen)}]cf_arrow_mid);
}
\NewChemArrow{==>}{
    \draw [chemarrow,double equal sign distance,double,-Implies]
        (cf_arrow_start)--(cf_arrow_end);
}
\begin{document}
    \[\begin{array}{r@{}l}
        \ch{CO^{*} + O^{*}} & \ch{->[ $k_1$ ] NO2^{*} + O^{*}} \\
        \ch{CO^{*} + O^{*}} & \ch{<=o>[ $k_2$ ] NO2^{*} + O^{*}} \\ % quasi equilibrium arrow
        \ch{CO^{*} + O^{*}} & \ch[label-offset=3pt]{<=0>[ $k_3$ ] NO2^{*} + O^{*}} \\
        \ch{CO^{*} + O^{*}} & \ch{-l>[ $k_4$ ] NO2^{*} + O^{*}} \\
        \ch{CO^{*} + O^{*}} & \ch{<=l>[ $k_5$ ] NO2^{*} + O^{*}} \\[1ex]
        \hline\rule{0pt}{4.5ex}
        \ch{CO^{*} + O^{*}} & \ch{==>[ $k_6$ ] NO2^{*} + O^{*}}
    \end{array}\]
\end{document}