Gas state symbol (g) in LaTeX (\text{(g)})

Where it is used

State symbol for the gaseous phase, attached to formulas of gases and vapours in equations.

Gas-phase species matter for equilibrium constants in pressure, K_p, and for ideal-gas calculations; marking them with (g) makes those dependencies explicit. Older texts sometimes use an upward arrow to show a gas escaping, but the state symbol is preferred today. A useful habit is labelling every species in a thermochemical equation so enthalpy values are unambiguous. If your document has many formulas, a macro like \newcommand{\gas}{\text{(g)}} prevents typos. \mathrm{(g)} gives the same upright result inside italic text.

Minimal compilable example

Paste this into an empty .tex file and compile it with pdfLaTeX, XeLaTeX or LuaLaTeX.

\documentclass{article}
\usepackage{amsmath}
\begin{document}
Gas state symbol (g): $\text{(g)}$

\[ \text{N}_2\text{(g)} + 3\text{H}_2\text{(g)} \to 2\text{NH}_3\text{(g)} \]
\end{document}

Related symbols

• Liquid\text{(l)}
• Solid\text{(s)}
• Aqueous\text{(aq)}
• Electrone^{-}
• Partial Charge\delta^{+}
• Triple Bond\text{C}\equiv\text{C}

Frequently asked questions

How do I write Gas state symbol (g) in LaTeX?

Type \text{(g)} in math mode, for example $\text{N}_2\text{(g)} + 3\text{H}_2\text{(g)} \to 2\text{NH}_3\text{(g)}$. Load amsmath first with \usepackage{amsmath}.

Which package do I need for \text{(g)}?

\text{(g)} needs amsmath: add \usepackage{amsmath} to your preamble before the document starts.

Can I use \text{(g)} in text mode, or only in math mode?

Both. \text{(g)} compiles in running text as well as inside $...$; in a formula keep it in math mode so it gets math fonts and spacing.