Syntax overview

AsciiChem is plain ASCII chemistry. Every construct is something a chemist can type on a standard keyboard. This page is the tour: every construct, one example each, links to the detail pages.

Atoms and elements

Source Rendered

H He C Fe Au

$\mathrm{H}\mathrm{He}\mathrm{C}\mathrm{Fe}\mathrm{Au}$

Atom reference →

Subscripts (multiplicity)

Source Rendered

H_2 H_2O H_2SO_4 C_6H_12O_6

${\mathrm{H}}_2{\mathrm{H}}_2\mathrm{O}{\mathrm{H}}_2\mathrm{S}{\mathrm{O}}_4{\mathrm{C}}_6{\mathrm{H}}_{12}{\mathrm{O}}_6$

Multi-character subscripts use braces: H_{2a}.

Prefix isotopes — the headline fix

Source Rendered

^14C ^131I ^238U

${}^{14}\mathrm{C}{}^{131}\mathrm{I}{}^{238}\mathrm{U}$

The prefix binds to the following atom. Why this matters →

Charges

Source Rendered

Ca^2+ Cl^- SO_4^2- Fe^3+

${\mathrm{Ca}}^{2+}{\mathrm{Cl}}^{-}\mathrm{S}{\mathrm{O}}_4^{2-}{\mathrm{Fe}}^{3+}$

IUPAC canonical form: number-then-sign. +2 is normalised to 2+.

Oxidation states

Source Rendered

Fe^(II) Fe^(III) Mn^(VII)

${\mathrm{Fe}}^{\mathrm{II}}{\mathrm{Fe}}^{\mathrm{III}}{\mathrm{Mn}}^{\mathrm{VII}}$

Roman numerals in parens.

Stoichiometric coefficients

Source Rendered

2H_2O 3H_2 10CO_2

$2{\mathrm{H}}_2\mathrm{O}3{\mathrm{H}}_{2}10\mathrm{C}{\mathrm{O}}_2$

Leading digits followed by an element or open bracket.

Groups with multiplicity

Source Rendered

Ca(OH)_2 (NH_4)_2SO_4 [Fe(CN)_6]

$\mathrm{Ca}{\left(\mathrm{O}\mathrm{H}\right)}_2{\left(\mathrm{N}{\mathrm{H}}_4\right)}_2\mathrm{S}{\mathrm{O}}_4\left[\mathrm{Fe}{\left(\mathrm{C}\mathrm{N}\right)}_6\right]$

Bracket variants (), [], {} are preserved through round-trip.

Bonds

Source Rendered

H-O-H H_2C=CH_2 HC#CH Re##Re C>-H C-<H NH_3~>BF_3 A~~B

$\mathrm{H}-\mathrm{O}-\mathrm{H}{\mathrm{H}}_2\mathrm{C}=\mathrm{C}{\mathrm{H}}_2\mathrm{H}\mathrm{C}\equiv \mathrm{C}\mathrm{H}\mathrm{Re}≣\mathrm{Re}\mathrm{C}\uparrow \mathrm{H}\mathrm{C}\downarrow \mathrm{H}\mathrm{N}{\mathrm{H}}_3\to \mathrm{B}{\mathrm{F}}_3\mathrm{A}\sim \mathrm{B}$

Eight kinds: single, double, triple, quadruple, wedge, hash, dative, wavy. Bond reference →

Stereochemistry

Source Rendered

(R)-CH_3 (S)-CH(OH)COOH (E)-CH=CH (Z)-A=B (alpha)-C (β)-C

$\text{(R)-}\mathrm{C}{\mathrm{H}}_3\text{(S)-}\mathrm{C}\mathrm{H}\left(\mathrm{O}\mathrm{H}\right)\mathrm{C}\mathrm{O}\mathrm{O}\mathrm{H}\text{(E)-}\mathrm{C}\mathrm{H}=\mathrm{C}\mathrm{H}\text{(Z)-}\mathrm{A}=\mathrm{B}\text{(alpha)-}\mathrm{C}\text{(beta)-}\mathrm{C}$

Markers attach to molecules. Greek alpha/beta typed words are accepted alongside α/β. Stereo reference →

Lewis structures

Source Rendered

:O ::O Cl. O=O..

$\text{:}\mathrm{O}\text{::}\mathrm{O}\mathrm{Cl}\text{.}\mathrm{O}=\mathrm{O}\text{..}$

Prefix : for lone pairs; suffix . for radical electrons.

Reactions

Source Rendered

2H_2 + O_2 -> 2H_2O HCl + NaOH -> NaCl + H_2O N_2 + 3H_2 <=>[Fe][400°C] 2NH_3

$2{\mathrm{H}}_2+{\mathrm{O}}_2\to 2{\mathrm{H}}_2\mathrm{O}\mathrm{H}\mathrm{Cl}+\mathrm{Na}\mathrm{O}\mathrm{H}\to \mathrm{Na}\mathrm{Cl}+{\mathrm{H}}_2\mathrm{O}{\mathrm{N}}_2+3{\mathrm{H}}_2\underset{\mathrm{Fe}}{\overset{\text{400°C}}{\rightleftharpoons }}2\mathrm{N}{\mathrm{H}}_3$

Four arrow kinds: forward ->, reverse <-, equilibrium <=>, resonance <->. Conditions in [above][below] brackets. Reaction reference →

Reaction cascades

Source Rendered

A -> B -> C 2A -> 2B -> 2C A <=>[Fe][T] B -> C

$\mathrm{A}\to \mathrm{B}\to \mathrm{C}2\mathrm{A}\to 2\mathrm{B}\to 2\mathrm{C}\mathrm{A}\underset{\mathrm{Fe}}{\overset{\mathrm{T}}{\rightleftharpoons }}\mathrm{B}\to \mathrm{C}$

Multi-step chains promote to a single ReactionCascade. Cascade reference →

Electron configurations

Source Rendered

1s^2 2s^2 1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^10

${\mathrm{1s}}^2 {\mathrm{2s}}^2 {\mathrm{1s}}^2 {\mathrm{2s}}^2 {\mathrm{2p}}^6 {\mathrm{3s}}^2 {\mathrm{3p}}^6 {\mathrm{4s}}^2 {\mathrm{3d}}^{10}$

Two or more orbital^occupancy pairs.

Embedded math

Source Rendered

`K_c = [P]/[R]` `x^2 + y^2` `rate = k[A]^2[B]`

${\displaystyle K_c=\frac{P}{R}}{\displaystyle x^2+y^2}{\displaystyle rate=k{\left[A\right]}^2\left[B\right]}$

Backtick-delimited runs are parsed by Plurimath. Embedded math reference →

Combining constructs

Real chemistry mixes everything:

Source Rendered

^14C_6H_12O_6 + 6O_2 -> 6CO_2 + 6H_2O `Delta G = -2870 kJ/mol`

${{}^{14}\mathrm{C}}_6{\mathrm{H}}_{12}{\mathrm{O}}_6+6{\mathrm{O}}_2\to 6\mathrm{C}{\mathrm{O}}_2+6{\mathrm{H}}_2\mathrm{O}{\displaystyle \Delta G=-2870k\frac{J}{m}ol}$

A radioactive glucose combustion with embedded thermodynamics.

Where to next?

Per-construct detail

Each syntax page has worked examples and round-trip behaviour. Start with Atoms.

The model

Every construct maps to a model class. See The model for the layer diagram and per-class reference.

Round-trip conformance

The Text formatter is the canonicaliser. See Round-trip conformance.

IUPAC mapping

Every construct’s spelling traced to its IUPAC source. See IUPAC mapping.