Documentation / Search syntax

Search syntax

Cheméo's search box understands more than names. The same box takes a chemical name, a formula, a structure, or a numeric property range, and works out what you meant. This page is the full grammar.

Text: names, synonyms, CAS numbers

Type a name and Cheméo searches names, synonyms and identifiers.

ethanol
acetic acid
64-17-5

Matching is case-insensitive and tolerant of small differences, so a near miss still finds the compound. Several words are combined: ethyl acetate looks for compounds matching both.

Formulas

A molecular formula is recognised by its shape and searched as a formula, not as text.

C2H6O
C6H12O6
AlCl3

Charges are understood (SO4-2, Na+), and so are parenthesised groups (Ca(OH)2).

Structures: SMILES, InChI, InChIKey

Paste a structure and Cheméo detects the format:

CCO
InChI=1S/C2H6O/c1-2-3/h3H,2H2,1H3
LFQSCWFLJHTTHZ-UHFFFAOYSA-N

A single SMILES searches for that exact structure. To find structurally similar compounds instead, use the similarity search from the structure drawing tool.

Property ranges

Every numeric property has a short key, and key: filters or ranges on it. The keys are the ones listed on the statistics page; common ones are tb (boiling point), tc (critical temperature), mp (melting point) and density.

Units are the ones shown on the property, SI throughout (kelvin for temperatures, for example). Ranges combine with everything else: C6 tb:300;400 is a formula constraint and a boiling-point range together.

Showing extra columns

show: adds property columns to the results, so you can compare at a glance:

alcohol show:tb,tc,density

Putting it together

A query is a series of terms, each read on its own and then intersected:

benzene tb:340;360 show:density

finds compounds matching "benzene" with a boiling point between 340 and 360, and shows their density in the results.