You're close. In the modified example below, I'm using the array
environment and define a special column type, L
', that's automatically in text mode. The reason this works is because l
, c
, and r
are automatically in math mode in an array
environment.
Note the second intercolumn specifier, @{{}={}}
: The pairs of {}
curly braces before and after the =
sign are there to inform TeX that the =
sign is to be treated as a so-called mathrel
object. In case this sounds a bit cryptic: mathord
, mathbin
, and mathrel
objects each have different amounts of whitespace before and after them. An easy way to make TeX treat a =
symbol as a mathrel
object even though it occurs in a non-equation setting is to pre- and post-fix it with (empty) math "atoms", viz., {}
.
Note also that it's not necessary to use the align
environment as there is really only one "equation" in the example.
\documentclass{article}
\usepackage{array,amsmath}
\newcolumntype{L}{>$l<$}
\begin{document}
\begin{equation*}
\begin{array}{L@{\quad}c@{{}={}}c}
some text: & x^2 & x^2 \\
more thoughts: & y^2 & y^2 \\
really deep thoughts: & z^2 & z^2
\end{array}
\end{equation*}
\end{document}