Chemical Equation

When writing chemical formulas in $LATEX$, you need to wrap the formula or equation in \ce{}. For example, to write sulfuric acid, you should use \ce{H2SO4}: $\mathrm{H}{\phantom{A}}_2\mathrm{SO}{\phantom{A}}_4$.

Inorganic Compounds

• Integers: Subscripts, charges, oxidation numbers

  \ce{CO2}: $\mathrm{CO}{\phantom{A}}_2$, \ce{H+}: $\mathrm{H}{\phantom{A}}^{+}$, \ce{Cl-}: $\mathrm{Cl}{\phantom{A}}^{-}$, \ce{Cu^2+}: $\mathrm{Cu}{\phantom{A}}^{2+}$, etc. For instance, in the case of copper(II) ion, if you don't add ^, it will appear as \ce{Cu2+}: $\mathrm{Cu}{\phantom{A}}_2{\phantom{A}}^{+}$.

  Oxidation numbers are shown like iron(II) \ce{Fe^{II}}: $\mathrm{Fe}{\phantom{A}}^{\mathrm{II}}$, and lead(IV) \ce{Pb^{IV}}: $\mathrm{Pb}{\phantom{A}}^{\mathrm{IV}}$.

• Fractional subscripts

  Like regular math expressions in $LATEX$, you can use fractions, e.g., \ce{Fe(CN)_{\frac62}}: $\mathrm{Fe}(\mathrm{CN}){\phantom{A}}_{\frac{6}{2}}$.

• Parentheses, square brackets, curly braces

  Parentheses: \ce{(NH4)2S}: $(\mathrm{NH}{\phantom{A}}_4){\phantom{A}}_2\mathrm{S}$, square brackets: \ce{[AgCl2]-}: $[\mathrm{AgCl}{\phantom{A}}_2]{\phantom{A}}^{-}$, curly braces: \ce{[\{(x2)3\}2]^3+}: $[\text{(x2)3}{\phantom{A}}_2]{\phantom{A}}^{3+}$.

  Note

  For curly braces, an escape character is needed to display them properly.

• Superscripts and subscripts: Isotopes, molecular ions

  \ce{^{227}_{90}Th+}: ${\phantom{A}}_{\phantom{90}}^{\phantom{227}}{\phantom{A}}_{\phantom{2}90}^{\phantom{2}227}\mathrm{Th}{\phantom{A}}^{+}$, \ce{H^2+}: $\mathrm{H}{\phantom{A}}^{2+}$.

• Dots: Radicals, hydrates

  \ce{Cl*}: $\mathrm{Cl}\cdot$, \ce{*CH3}: $\cdot \mathrm{CH}{\phantom{A}}_3$, \ce{KCr(SO4)2*12H2O}: $\mathrm{KCr}(\mathrm{SO}{\phantom{A}}_4){\phantom{A}}_2\cdot 12\mathrm{H}{\phantom{A}}_2\mathrm{O}$.

Organic Compounds

• Chemical Bonds

  Single bond \ce{CH3-CHO}: $\mathrm{CH}{\phantom{A}}_3-\mathrm{CHO}$, double bond \ce{CH2=CH2}: $\mathrm{CH}{\phantom{A}}_2=\mathrm{CH}{\phantom{A}}_2$, triple bond \ce{CH#CH}: $\mathrm{CH}\equiv \mathrm{CH}$.

  Other bond types include \ce{A\bond{~}B\bond{~-}C}: $\mathrm{A}\phantom{-}\text{-}\text{-}\text{-}\mathrm{B}-\phantom{-}\text{-}\text{-}\text{-}\mathrm{C}$, \ce{A\bond{~--}B\bond{~=}C\bond{-~-}D}: $\mathrm{A}-\phantom{-}\text{-}\text{-}\text{-}-\mathrm{B}-\phantom{-}\text{-}\text{-}\text{-}-\mathrm{C}--\phantom{-}\text{-}\text{-}\text{-}\mathrm{D}$, \ce{A\bond{...}B\bond{...}C}: $\mathrm{A}\cdot \cdot \cdot \mathrm{B}\cdot \cdot \cdot \mathrm{C}$.

• Italicized: cis and trans

  In organic chemistry, the terms cis and trans are written in italics to denote stereoisomers. Since math formulas are italicized in LaTeX, wrap them in $ signs, e.g., $$\ce{$cis${-}CH3CH-CHCH3}$$:

  $$cis\text{-}\mathrm{CH}{\phantom{A}}_3\mathrm{CH}-\mathrm{CHCH}{\phantom{A}}_3$$

Chemical Equations

• Arrows: Reaction directions

  Different arrow types can be used, such as \ce{->}: $⟶$, \ce{<=>}: $\stackrel{-\rightharpoonup }{\leftharpoondown -}$, \ce{<=>>}: $\stackrel{-\rightharpoonup }{\leftharpoondown }$, and \ce{<<=>}: $\stackrel{\phantom{-}\rightharpoonup }{\leftharpoondown -}$.

  You can also add reaction conditions easily.

  • Example:

    $$
    \ce{2H2 + O2 ->[\Delta] H2O}
    $$
    
    $$
    \ce{N2 + H2 ->[{catalyst}][{hightemp}] NH3}
    $$

  • Output:

    $$2\mathrm{H}{\phantom{A}}_2+\mathrm{O}{\phantom{A}}_2\stackrel{\mathrm{\Delta }}{\to }\mathrm{H}{\phantom{A}}_2\mathrm{O}$$$$\mathrm{N}{\phantom{A}}_2+\mathrm{H}{\phantom{A}}_2\underset{\text{hightemp}}{\overset{\text{catalyst}}{\to }}\mathrm{NH}{\phantom{A}}_3$$

• Arrows: Precipitate and gas

  \ce{Ca(OH)2 + CO2 = CaCO3 v + H2O}：

  $$\mathrm{Ca}(\mathrm{OH}){\phantom{A}}_2+\mathrm{CO}{\phantom{A}}_2=\mathrm{CaCO}{\phantom{A}}_3\downarrow +\mathrm{H}{\phantom{A}}_2\mathrm{O}$$

  \ce{Fe + 2H+ = H2 ^ + Fe^2+}：

  $$\mathrm{Fe}+2\mathrm{H}{\phantom{A}}^{+}=\mathrm{H}{\phantom{A}}_2\uparrow +\mathrm{Fe}{\phantom{A}}^{2+}$$

Additional Content

• Notes below text

  Isomers and allotropes often require annotations beneath the chemical formula, e.g., \underset{\text{glucose}}{\ce{C6H12O6}}:$\underset{\text{glucose}}{\mathrm{C}{\phantom{A}}_6\mathrm{H}{\phantom{A}}_{12}\mathrm{O}{\phantom{A}}_6}$.

• Multiline reactions

  Use the align environment by adding \begin{align*}...\end{align*}.

  Start each line with & and end with \\.

  • Example:

    $$
    \begin{align*}
    & \ce{CO2 + 3H2 <=> CH3OH + H2O} \\
    & \ce{CO2 + H2 <=> CO + H2O} \\
    & \ce{CO + 2H2 <=> CH3OH} \\
    & \ce{CH3OH <=> CH3OCH3 + H2O}
    \end{align*}
    $$

  • Output:

    $$\begin{array}{rl}& \mathrm{CO}{\phantom{A}}_2+3\mathrm{H}{\phantom{A}}_2\stackrel{-\rightharpoonup }{\leftharpoondown -}\mathrm{CH}{\phantom{A}}_3\mathrm{OH}+\mathrm{H}{\phantom{A}}_2\mathrm{O}\\ & \mathrm{CO}{\phantom{A}}_2+\mathrm{H}{\phantom{A}}_2\stackrel{-\rightharpoonup }{\leftharpoondown -}\mathrm{CO}+\mathrm{H}{\phantom{A}}_2\mathrm{O}\\ & \mathrm{CO}+2\mathrm{H}{\phantom{A}}_2\stackrel{-\rightharpoonup }{\leftharpoondown -}\mathrm{CH}{\phantom{A}}_3\mathrm{OH}\\ & \mathrm{CH}{\phantom{A}}_3\mathrm{OH}\stackrel{-\rightharpoonup }{\leftharpoondown -}\mathrm{CH}{\phantom{A}}_3\mathrm{OCH}{\phantom{A}}_3+\mathrm{H}{\phantom{A}}_2\mathrm{O}\end{array}$$