Math & Science ⇒ Alignment inside the \align enviroment

[Eenzc]

Hello,

I'm using \begin{align} instead of \begin{equation} because it allows me to align my equals signs and reaction <=> symbols above each other.

However In one case I have a third column in which I have a series of numbers that I would like to align above each other. This could be easily acomplished if I could set the alignment of that column to left align.

Is there a way to do this inside the align enviroment?

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%%%% Math Packages 
\usepackage{amsmath}
\usepackage{amsthm}
\usepackage{amsfonts}
\usepackage{amssymb}

%%%% Chemistry Specific
\usepackage{sistyle} % includes SI style sheets
\usepackage[version=3]{mhchem}

%%%% Custom standard symbol

\makeatletter
\providecommand\barcirc{\mathpalette\@barred\circ}
\def\@barred#1#2{\ooalign{\hfil$#1-$\hfil\cr\hfil$#1#2$\hfil\cr}}
\newcommand\stst{^{\protect\barcirc}}

%%%%%%%%%%%%

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\begin{align}
\ce{O2 + 4H+ + 4e}	~& \ce{<=> 2H2O}   ~& E\stst : \SI{+1.2300}{V}  \\
\ce{O2 + 2H+ + 2e} 	~& \ce{<=> H2O2}   ~& E\stst : \SI{+0.695}{V}
\end{align}

The problem being that because the numbers are to a different precision the column is skewed.

Many thanks.

[localghost]

In this case the alignat environment is more suitable.

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\begin{alignat}{2}
  \ce{O2 + 4H+ + 4e} & \ce{<=> 2H2O} &\qquad\qquad\qquad E\stst &: \SI{+1.2300}{V}  \\
  \ce{O2 + 2H+ + 2e} & \ce{<=> H2O2} & E\stst &: \SI{+0.695}{V}
\end{alignat}

A good description of this environment is given in the "Math mode" document.

One additional hint at the end. Perhaps the \ominus symbol does it instead of your complex defined \stst command.

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\[
  E^\ominus
\]

Best regards
Thorsten¹

[Eenzc]

Thanks that was very helpful.