Why Chemical Equations?

Chemical Equations were brought to Socrative to make the experience of questioning your students more seamless.

Teachers in the Sciences realm can enjoy chemical formulae and equations using the Equation Editor to display element symbols, superscript and subscript notation, ions and isotopes, bonds, equilibrium reaction arrows etc. - allowing a more flexible display and more natural input of chemical formulae and equations.

Using Chemical Equations

With the Equation Editor, you can use the mhchem notation to write Chemical Equations and Formulas, you can also insert math symbols and equations at the same time.

Chemical Equations have a descriptor to let the equation editor know your intent. To get started, write \ce{formulae}. The delimiter \ce{...} is required since you can use mathematics delimiters for chemical formulas.


Chemical Equation Notation

  1. Formulae

  2. Amounts

  3. Equations

  4. Charges

  5. Stoichiometric numbers

  6. Nuclides, isotopes

  7. Reaction arrows

  8. Parentheses, brackets, braces

  9. Variables like x, n, 2n+1

  10. Bonds

  11. Addition compounds

  12. Oxidation States

  13. Equation Operators

  14. Precipitate and gas

  15. Unpaired electrons, radical dots

  16. Kröger-vink notation (not supported for latex yet)

Formulae

You can use the delimiter \ce(...) and insert your formula.

\ce{ H2O }

\ce{ (NH4)2S }

Amounts

Place amounts directly in front of a formula. A small space will be inserted automatically.

\ce{ 2H2O }

\ce{ 1/2H2O }

Equations

\ce{CO2 + C -> 2 CO}

\ce{Hg^2+ ->[I-] HgI2 ->[I-] [Hg^{II}I4]^2-}

Charges

\ce{H+}

\ce{CrO4^2-}

\ce{Y^99+}

\ce{[AgCl2]-}

Stoichiometric numbers

\ce{2 H2O}

\ce{2H2O}

\ce{0.5 H2O}

\ce{1/2 H2O}

\ce{(1/2) H2O}

\ce{$n$ H2O}

Nuclides, isotopes

It might be ambiguous whether a superscript belongs to the left or right element. There is automatic detection (digits only = mass number = belongs to the right side), but to ensure it, you can type {} as a separator.

Although the below syntax works in most contexts, occasionally, a leading pair of braces {} may be required \ce{ {}^{227}_{90}Th+ }

\ce{^{227}_{90}Th+}

\ce{^227_90Th+}

\ce{^{0}_{-1}n^{-}}

\ce{^0_-1n-}

\ce{H{}^3HO}

\ce{H^3HO}

Reaction arrows

Each arrow can take two optional arguments: one for above and one for below. The arrow arguments use the same input syntax as the \ce command.

\ce{A -> B}

\ce{A <- B}

\ce{A <-> B}

\ce{A <--> B}

\ce{A <=> B}

\ce{A <=>> B}

\ce{A <<=> B}

\ce{A ->[H2O] B}

upright text

\ce{A ->[{text above}][{text below}] B}

italic math

\ce{A ->[$x$][$x_i$] B}

Parentheses, brackets, braces

Use parentheses ( ) and brackets [ ] normally. Write braces as \{ \}. For large parentheses, \left and \right macros need to be in the same math environment, so you might have to put \ce into $ into \ce, but that’s fine.

\ce{(NH4)2S}$

\ce{[\{(X2)3\}2]^3+}$

Variables like x, n, 2n+1

If a more complex term is not properly recognized, you can switch to math mode (= italics) explicitly.

\ce{NO_x}

\ce{Fe^n+}

\ce{x Na(NH4)HPO4 ->[\Delta] (NaPO3)_x + x NH3 ^ + x H2O}

Bonds

The Equation Editor tries to differentiate whether \ce{-} should be a bond, a charge or a hyphen.

\ce{C6H5-CHO}

\ce{A-B=C#D}

\ce{A\bond{-}B\bond{=}C\bond{#}D}

\ce{A\bond{1}B\bond{2}C\bond{3}D}

Not Supported

\ce{A\bond{~}B\bond{~-}C}

Not Supported

\ce{A\bond{~--}B\bond{~=}C\bond{-~-}D}

\ce{A\bond{...}B\bond{....}C}

\ce{A\bond{->}B\bond{<-}C}

Addition compounds

You can use * or . to sum compounds

\ce{KCr(SO4)2*12H2O}

\ce{KCr(SO4)2.12H2O}

\ce{KCr(SO4)2 * 12 H2O}

Oxidation states

\ce{Fe^{II}Fe^{III}2O4}

Equation operators

\ce{A + B

\ce{A - B}

not to be confused with bonds

\ce{A = B}

not to be confused with bonds

\ce{A \pm B}

Precipitate and gas

Use v or (v) for precipitate (arrow down) and ^ or (^) for gas (arrow up), both separated by spaces.

\ce{SO4^2- + Ba^2+ -> BaSO4 v}

\ce{A v B (v) -> B ^ B (^)}

Unpaired electrons, radical dots

\ce{OCO^{.-}}

\ce{NO^{(2.)-}}

Kröger-vink notation (not supported for latex yet)

\ce{Li^x_{Li,1-2x}Mg^._{Li,x}$V$'_{Li,x}Cl^x_{Cl}}

\ce{O''_{i,x}}

\ce{M^{..}_i}

\ce{$V$^{4'}_{Ti}}

upright V = Vanadium, italic V = vacancy

\ce{V_{V,1}C_{C,0.8}$V$_{C,0.2}}

Not Supported Chemical Notation

  • We don’t fully support

    • states of aggregation,

    • crystal systems.

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