Take the 2-minute tour ×
TeX - LaTeX Stack Exchange is a question and answer site for users of TeX, LaTeX, ConTeXt, and related typesetting systems. It's 100% free, no registration required.

I would like to align some chemical reactions in my document. This is an example of what I did:

\begin{equation}
\nuclide[14][7]{N} + n \to \nuclide[14][6]{C} + p
\end{equation}

<Some text>

\begin{align*}
 &\nuclide[14][7]{N} + n \to \nuclide[11][5]{B} + \nuclide[4][2]{H}\\%
 &\nuclide[14][7]{N} + n \to \nuclide[12][6]{C} + \nuclide[3][1]{H}\\%

\end{align*}

I would like to align the first equation with the next two. How can I do?

share|improve this question
2  
Have you tried one of amsmath’s environments, say align? –  Qrrbrbirlbel Jan 3 '13 at 15:31
    
@FordPrefect: What was the sense of your change to Torbjorn’s edit in tex.stackexchange.com/revisions/89108/10? The way he made the indentation is exactly, how the syntax highlighting/markup system called Markdown expects it for showing code blocks. With your edit there came additional (useless) indentation. –  Speravir Jan 3 '13 at 21:43
1  
Re your edit: How long is <Some text>? For short text, use \intertext{<some text>} (or \shortintertext from mathtools) inside (!) one (!) align environment (or its kind). For long text (which indicates your paragraphs = empty lines in source) I’d advise against it. Though you could do it by some trickery with \hphantom and \mathllap (mathtools required). [cont …] –  Qrrbrbirlbel Jan 3 '13 at 22:15
    
[… cont] Can you extend your question: what should aligned to what? Maybe you are more interested in the fleqn option (see amsmath manual, p. 3). –  Qrrbrbirlbel Jan 3 '13 at 22:17

2 Answers 2

up vote 13 down vote accepted

Wouldn't it be easier to use a chemistry package like mhchem (together with the already proposed amsmath) instead of tensor? mhchem's \cee macro is defined especially for use in alignment environments like {align}. For text between aligned equations one can use amsmath's \intertext{}.

\documentclass{book}
\usepackage[version=3]{mhchem}
\usepackage{amsmath}

\begin{document}
\begin{align*}
 \cee{
   ^{14}_7N + n &-> ^{11}_5B  + ^4_2H \\
 }
 \intertext{Some text in between that is not aligned or anything.}
 \cee{
   ^{14}_7N + n &-> ^{12}_6C  + ^3_1H \\
   ^{16}_8O + n &-> ^{10}_4Be + ^7_4Be
 }
\end{align*}

\end{document}

enter image description here

Edit: In order to get the first equation numbered but not the second and third you have basically two options:

  1. Use {align} (without the star!) and suppress the numbers of the second and third equation via \notag or \nonumber.
  2. Use {align*} and add the number for the first manually by saying \tag{\refstepcounter{equation}\theequation}

Personally I prefer the first variant. BTW: if you haven't read it yet you might want to have a look at “Math Mode” by Herbert Voß.

\documentclass{book}
\usepackage[version=3]{mhchem}
\usepackage{amsmath}

\begin{document}

\begin{align}
 \cee{
   ^{14}_7N + n &-> ^{11}_5B  + ^4_2H \\
 }
 \intertext{Some text in between that is not aligned or anything.}
 \cee{
   ^{14}_7N + n &-> ^{12}_6C  + ^3_1H \nonumber \\
   ^{16}_8O + n &-> ^{10}_4Be + ^7_4Be \notag
 }
\end{align}

\begin{align*}
 \cee{
   ^{14}_7N + n &-> ^{11}_5B  + ^4_2H \tag{\refstepcounter{equation}\theequation}\\
 }
 \intertext{Some text in between that is not aligned or anything.}
 \cee{
   ^{14}_7N + n &-> ^{12}_6C  + ^3_1H \\
   ^{16}_8O + n &-> ^{10}_4Be + ^7_4Be 
 }
\end{align*}

\end{document}

enter image description here

share|improve this answer
    
Thank you, but how if I wanna number the first equation? –  Ford Prefect Jan 5 '13 at 10:02
    
@FordPrefect see my edited answer –  cgnieder Jan 5 '13 at 12:32
    
Thank you very much! I learned a lot. –  Ford Prefect Jan 6 '13 at 12:35

Try the align* environment, provided by amsmath package. To change the position of the aligment, change the & symbol.

\documentclass{book}
\usepackage{tensor}
\usepackage{amsmath}

\begin{document}
\begin{align*}
   &\nuclide[14][7]{N} + n \to \nuclide[11][5]{B}  + \nuclide[4][2]{H}\\
   &\nuclide[14][7]{N} + n \to \nuclide[12][6]{C}  + \nuclide[3][1]{H}\\
   &\nuclide[16][8]{O} + n \to \nuclide[10][4]{Be} + \nuclide[7][4]{Be}
\end{align*}
\end{document}
share|improve this answer
    
The environment align works very well. But how do I do if between equations I have some text (that I would like rest "normal")? –  Ford Prefect Jan 3 '13 at 17:06
    
@FordPrefect try \intertext{<text>}. Have you read Math Mode, yet? –  cgnieder Jan 3 '13 at 17:26
    
@FordPrefect, text between equations should be written on a normal line? Or centered? Please, exemplify it. –  Sigur Jan 3 '13 at 17:52
    
@Sigur I edited my question. Sorry for the bad explanations... –  Ford Prefect Jan 3 '13 at 21:43

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.