Chemfig Polymer 中的多个括号 - 无法消除错误

Question

我正在努力获取一个显示chemfig正确使用聚合过程的反应。

这是我正在使用的代码：

\begin{figure}[htb!]
\centering
\schemestart
\chemfig{R-C(-[2])(-[6])-C(-[2])(-[6])-C(-[2])(-[6])-\lewis{0.,C}(-[2])(-[6])}
\+
\chemfig{[@{left,0.5}]C(-[2])(-[6])=C(-[2])(-[6])[@{right,0.5}]}
%\polymerdelim[delimiters ={[]}, height = 40pt, indice = n]{left}{right}
\arrow
\chemfig{R-C(-[2])(-[6])-C(-[2])(-[6])-[@{left,0.5}]C(-[2])(-[6])-C(-[2])(-[6])-[@{right,0.5}]C(-[2])(-[6])-\lewis{0.,C}(-[2])(-[6])}
\polymerdelim[delimiters ={[]}, height = 40pt, indice = n]{left}{right}
\schemestop
\caption{}
\label{}
\end{figure}

这是目前的结果：

由于某种原因，第二个括号是我想要的，但第一个不是。似乎它没有得到 的规范\polymerdelim，所以我想我可能还需要在上面添加该行\chemfig。

如果我激活该线路

%\polymerdelim[delimiters ={[]}, height = 40pt, indice = n]{left}{right}

我收到此错误信息：

! Package pgf Error: No shape named left is known.See the pgf package documentation for explanation.Type H <return> for immediate help.... \chemfig

有人可以帮我吗？

谢谢你！

Answer 1

根据文档chemfig第 13 节，该语法@{<name>, <coeff>}只能在键的可选参数的开头使用。在\chemfig您的第二个示例中

\chemfig{[@{left,0.5}]C(-[2])(-[6])=C(-[2])(-[6])[@{right,0.5}]}

可选参数[@{left,0.5}]和[@{right,0.5}]没有相应的键，因此节点left和right永远不会被创建。

选项1

如果你对开始和结束债券没意见，那么使用

\chemfig{C(-[2])(-[6])(-[@{left,0.5}4])=C(-[2])(-[6])-[@{right,0.5}]}
\polymerdelim[delimiters={[]}, height=40pt, depth=, indice=n]{left}{right}

选项 2

如果要保留无键样式，可以使用@{<name>}<atom>为原子添加节点，并使用\polymerdelim选项open xshift和close xshift调整分隔符的位置。请注意，在这种情况下，左右间距不会自动调整。

\chemfig{@{left}C(-[2])(-[6])=@{right}C(-[2])(-[6])}
\polymerdelim[delimiters={[]}, height=40pt, depth=, indice=n, 
  open xshift=-8pt, close xshift=]{left}{right}

选项 3

这是选项 1 的变体，其中指定了起始和终止键，但未绘制（通过键选项[,,,draw=none]）。为了获得更好的水平间距，这两个键也被缩短了（通过键选项[,0.5,,,]) and the position of nodes are adjusted (from@{left, 0.5} to@{left, 1}`）。

\chemfig{C(-[2])(-[6])(-[@{left,1}4,.5,,,draw=none])=C(-[2])(-[6])-[@{right,1},.5,,,draw=none]}
\polymerdelim[delimiters={[]}, height=40pt, depth=, indice=n]{left}{right}

完整示例：

\documentclass[margin=20pt]{standalone}
\usepackage{chemfig}

\begin{document}

\schemestart
  \chemfig{R-C(-[2])(-[6])-C(-[2])(-[6])-C(-[2])(-[6])-\lewis{0.,C}(-[2])(-[6])}
  \+
  %% option 1
  % \chemfig{C(-[2])(-[6])(-[@{left,0.5}4])=C(-[2])(-[6])-[@{right,0.5}]}
  % \polymerdelim[delimiters={[]}, height=40pt, depth=, indice=n]{left}{right}
  %
  %% option 2
  % \chemfig{@{left}C(-[2])(-[6])=@{right}C(-[2])(-[6])}
  % \polymerdelim[delimiters={[]}, height=40pt, depth=, indice=n, 
  %   open xshift=-8pt, close xshift=]{left}{right}
  %% option 3
  \chemfig{C(-[2])(-[6])(-[@{left,1}4,.5,,,draw=none])=C(-[2])(-[6])-[@{right,1},.5,,,draw=none]}
  \polymerdelim[delimiters={[]}, height=40pt, depth=, indice=n]{left}{right}
  \arrow
  \chemfig{R-C(-[2])(-[6])-C(-[2])(-[6])-[@{left,0.5}]C(-[2])(-[6])-C(-[2])(-[6])-[@{right,0.5}]C(-[2])(-[6])-\lewis{0.,C}(-[2])(-[6])}
  \polymerdelim[delimiters ={[]}, height=40pt, depth=, indice=n]{left}{right}
\schemestop

\end{document}