Misplaced alignment tab character &

TeX Output

./example.tex:5: Misplaced alignment tab character &.
l.5   x = 1 &
              y = 2

Explanation

The ampersand symbol (&) is a reserved TeX alignment delimiter. This error occurs when:

1. & is used inside an unaligned math environment (like equation, equation*, or inline $ ... $).
2. & is used in normal prose without escaping it (e.g. Barnes & Noble).
3. Alignment environments like matrix or align are used without loading \usepackage{amsmath}.

How to Fix

• In math mode, replace equation* with align* or wrap the expressions inside \begin{aligned} ... \end{aligned}:

  \begin{align*}
    x = 1 & y = 2
  \end{align*}
  

• In regular text, escape the ampersand with a backslash: \&.