LaTeX 中的均裂图

Question

我想写出以下方程式；特别是左边的两个红色箭头。

可以吗chemfig？谢谢您的帮助 :)

Answer 1

是的，可以做到。

\documentclass{article}
\usepackage{chemfig}


\begin{document}
    
    \schemestart
    \setchemfig{bond offset=2pt}
    \chemfig{@{a}A-[,0.5]@{b}-[,0.2]@{b2}-[,0.5]@{c}B}
    \arrow
    \chemfig{\charge{55=\.}{A}+\charge{55=\.}{B}}
    \schemestop
    \chemmove{\draw[-{Latex[length=2mm, width=1mm]},red,shorten >=2pt](b)..  controls +(85:0.5cm) and +(85:0.5cm)..  (a);}
    \chemmove{\draw[-{Latex[length=2mm, width=1mm]},red,shorten >=2pt](b2)..  controls +(95:0.5cm) and +(95:0.5cm)..  (c);}
    
\end{document}

或者更像你的照片：

\documentclass{article}
\usepackage{chemfig}


\begin{document}
    
    
    
    \schemestart
    \setchemfig{bond offset=2pt}
    \chemfig{@{a} A-[,0.3]@{b}-[,0.1]@{b2}-[,0.3]B @{c}}
    \arrow
    \chemfig{\charge{55=\.}{A}+\charge{55=\.}{B}}
    \schemestop
    \chemmove{\draw[-{Stealth[right][length=2mm, width=1mm]},red,shorten >=3pt](b)..  controls +(90:0.4cm) and +(80:0.4cm)..  (a);}
    \chemmove{\draw[-{Stealth[left][length=2mm, width=1mm]},red,shorten >=3pt](b2)..  controls +(90:0.4cm) and +(100:0.4cm)..  (c);}
    
\end{document}

Answer 2

\documentclass{article}
\usepackage{chemfig}

\begin{document}

\schemestart
\chemfig{@{a}A(-[@{bd2,0.6},,,,draw=none]\phantom{B})-[@{bd1,0.4}]@{b}B}
\arrow{->}
\chemfig{\charge{0=\.}{A} \ \+\ \charge{180=\.}{B}}
\chemmove{
    \draw[red,-{Stealth[right,width=4pt]},shorten <=1pt,shorten >=1pt]
            (bd1) .. controls +(90:4ex) and +(85:3ex) .. (a);
    \draw[red,-{Stealth[left,width=4pt]},shorten <=1pt,shorten >=1pt]
            (bd2) .. controls +(90:4ex) and +(95:3ex) .. (b);
}
\schemestop

\end{document}

Answer 3

我知道我来晚了一点，但另一种方法是：

\documentclass[border=1cm]{standalone}
\usepackage{tikz}
\usetikzlibrary{arrows}
\usepackage{chemfig}
\begin{document}
\schemestart
\chemfig{@{a}A(-[@{bd2,0.6},,,,draw=none]\phantom{B})-[@{bd1,0.4}]@{b}B}
\arrow
\chemfig{\charge{0=\.}{A} \ \+\ \charge{180=\.}{B}}
\schemestop
\chemmove{
\draw[red,thick,-right to,shorten <=3pt,shorten >=3pt]
(bd1.north) ..controls +(90:5mm) and +(90:5mm) .. (a.north) ;
\draw[red,thick,-left to,shorten <=3pt,shorten >=3pt]
(bd2.north) ..controls +(90:5mm) and +(90:5mm) .. (b.north) ;
}
\end{document}

和-right to鱼叉由命令库-left to提供。arrows\usepackage{tikz} \usetikzlibrary{arrows}

改变锚点位置可以获得更好的外观，尝试..(a.north)用..(a.west)和..(b.north)替换..(b.east)。

弯曲的鱼叉或弯曲的半头箭头是描述化学中一个电子运动的正确方法。全头箭头描绘两个电子的运动。

我确信您已经意识到了这一点，但只是告知那些可能没有化学背景并且可能没有看到箭头的细微差别的专家。

Answer 4

\documentclass[margin={2mm 4mm}, width=25cm]{standalone}
\usepackage[utf8x]{inputenc}
\usepackage{stix}
\usepackage{chemfig}
\usepackage[version=3]{mhchem}
\usepackage{amssymb}
\setatomsep{1.8em}
\usetikzlibrary{calc,arrows.meta}
\tikzset{myedge/.style={->, -{Latex[#1]}}}

\begin{document}


\schemestart
%
\chemfig{@aA-[@b]-[@c]@dB}
 \arrow{->}
  %
  \chemfig{\lewis{0.,A}}
  %
  \+
   %
   \chemfig{\lewis{4.,B}}
%
\chemmove{
    \draw[myedge={right},red,shorten <=1pt,shorten >=1pt](b).. controls +(90:6mm) and +(60:6mm)..(a);
    \draw[myedge={left},red,shorten <=1pt,shorten >=1pt](c).. controls +(90:6mm) and +(120:6mm)..(d);
}
\schemestop


\end{document}