Molecular Formula to Structure Search

In short: Enter a formula such as C9H8O4 and browse matching PubChem structures, names, SMILES, formula, MW, and CID. It is free, works in your web browser and needs no download.

Enter a formula such as C9H8O4 or C6H12O6 to browse multiple possible PubChem structure matches. Formula searches are often ambiguous, so this page shows candidate molecules instead of pretending there is only one structure.

Why Formula Searches Return Multiple Structures

A molecular formula only tells you atom counts. Many compounds can share the same formula but have different connectivity, stereochemistry, or functional groups. Use the candidate names, images, and SMILES to choose the intended molecule.

Why one formula has many structures

A molecular formula only counts atoms; it says nothing about how they are connected. Different compounds with the same formula are isomers. C₂H₆O is both ethanol (an alcohol) and dimethyl ether, two compounds with very different boiling points. Larger formulas can correspond to thousands of known compounds, which is why this tool shows a list of candidates rather than a single answer.

Narrowing down the candidates

• Degree of unsaturation: for C_cH_hN_nX_x, DoU = (2c + 2 + n − h − x) ÷ 2. Each ring or π bond counts as one. C₆H₆ gives 4, consistent with benzene's ring plus three double bonds.
• Spectroscopy: IR shows functional groups, and NMR shows how many distinct environments are present.
• Context: the reaction you ran or the source of the sample often rules out most candidates.

Example: C₉H₈O₄ returns aspirin among other matches; check the CID and structure before you use one. If you already know the name, Name to Structure is faster.