About this dataset
“Common molecule” is a practical rather than formal chemical category. This list brings together compounds encountered in air, water, food, living systems, laboratories, and industry so that familiar names can be connected to formulas and machine-readable structures.
Some entries, such as oxygen and carbon dioxide, are discrete covalent molecules. Others, such as sodium chloride, are more accurately described as ionic compounds with extended lattices in the solid state. They remain useful here because they are routinely searched and compared alongside familiar molecules.
How formulas relate to everyday names
A common name can hide important chemical detail. “Sugar” may refer to sucrose, glucose, fructose, or another carbohydrate, while “alcohol” may refer specifically to ethanol or to an entire functional class. The table resolves each row to a formula, structure, and identifier.
A formula is not always unique to one substance. Ethanol and dimethyl ether both have the formula C₂H₆O but different connectivity and properties. Use the name, SMILES, and PubChem CID together when a precise identity matters.
Using the dataset
The collection is suited to demonstrations, lessons, format conversion, descriptor calculations, and smoke tests across chemistry tools. Categories say where you typically meet each compound, such as atmospheric gas, food acid, solvent, or flavor and fragrance. They are practical labels, not a formal ontology or a ranking of abundance.
Amino acids, drugs, and long homologous series such as the alkanes have their own datasets, so this list stays focused on compounds people encounter in everyday life.
How this dataset was assembled
Rows are chosen for how often people meet them in daily life: air, food and drink, cleaning products, fuels, and introductory chemistry. Homologous series, amino acids, and drugs have their own datasets instead of padding this list. Ionic compounds such as table salt are included with a note that they form lattices rather than discrete molecules. Formulas are written conventionally (HCl, H2SO4, NaOH) and structures come from the cited PubChem record.
Each row retains source identifiers where available. Molecular weight is calculated from the recorded formula, and the original names, structures, classifications, and database links remain visible so individual entries can be checked before reuse.
License and citation
This compilation is free to download and reuse under the Creative Commons Attribution 4.0 International license. Credit ProteinIQ and the original sources when you share it or publish results that use it.
Suggested citation: ProteinIQ (2026). List of common molecules, version 2026.10.05. https://proteiniq.io/datasets/common-molecules
Sources and further reading
- PubChem: Canonical compound identifiers, names, formulas, structures, SMILES, and downloadable compound records. NCBI places no restrictions on PubChem data, though original submitters may retain rights in submitted records.
- ChEBI: Chemical ontology classes, biological roles, synonyms, formulas, SMILES, InChI, and ChEBI identifiers. ChEBI provides ontology, flat-file, SDF, and SQL downloads from EMBL-EBI.
- NIST Chemistry WebBook: Reference physical chemistry data and diatomic constants for selected species. NIST SRD 69 should be cited and linked rather than mirrored wholesale.
- OpenStax Chemistry: Chemistry definitions used for educational polarity, bonding, organic chemistry, and molecule-class explanations.