Public Computational Chemistry Database Project

Please use the following web-api within about two thousands times in a day per one research group,
because server resources are very limited. (This restriction will be relaxed in the near future)

Search Data for PubChemQC
- View & Web API -

You can visualize a molecular by accessing the following URL.


You can also use the following URL, where only one SMILES representation is used to generated 2D and 3D molecular structures. Here, we do not use any quantum chemistry calculation results. Please note this point.


If a SMILES representation contains characters not permitted in URL, please encode it using the "encodeURIComponent()" in Javascript etc. Our "2D conversion tool" may be easy to use this URL, because it automatiically create links for molecules.

You can get several electronic structure properties through Web APIs.

The following Web API return a Json data containing several basic properties, such as PCCDB-ID, Canonical SMILES, HOMO-LUMO gap, HOMO energy, LUMO energy, Excitation energy, and so on.


For example, we can obtain a Json by using "curl" command.

                    $ curl

                        "homo_lumo_gap": 4.512,
                        "homo_energy": -4.528,
                        "lumo_energy": -0.016,
                        "excitation_energy": 3.749,
                         etc ...

If a molecule does not exist in the database, "null (None)" is returned.

                    $ curl

For example you can also get a Json data in a Python script.

                    import requests
                    res = requests.get("")

                    if res.status_code==200:
                        prop_json = res.json()
                        print prop_json

To get a molecular strucure optmized by the B3LYP/6-31G* method, you can use the following Web API.


The Mulliken and Lowdin charges are also obtained from the returned Json.

You can get SDF-format molecular data by using the following Web API.