chemeq 2.12-3 (armhf binary) in ubuntu bionic

 chemeq is a basic standalone filter written in C language,
 flex and bison. It inputs strings like:
  2H2 + O2 ---> 2 H2O
 then it outputs LaTeX code and messages about the equilibrium of a
 chemical reaction.
 .
  example:~/src$ echo "2H2 + O2 ---> 2 H2O" | chemeq -lc
  2\,H_{2}\,+\,O_{2}\,\rightarrow\,2\,H_{2}O
  OK