Acid dissociation constants (pKa) of chemical compounds
The pKa — how readily a compound gives up a proton in water, lower meaning a stronger acid — of about 280 acids, bases and other compounds recorded in Wikidata, with the second and third pKa of polyprotic acids where recorded. One row per compound.
Columns
Stable keys — use them in the API, SQL and code
| Key | Name | Type | Description |
|---|---|---|---|
| wikidata | Wikidata | entity | — |
| name | Compound | string | — |
| formula | Formula | string | Chemical formula as recorded in Wikidata. |
| pka | pKa | number | First (or only) acid dissociation constant, as −log10 Ka in water. |
| temperature_c | At temperature | number · °C | Temperature the chosen first pKa was measured at, when recorded. |
| pka2 | pKa₂ | number | Second dissociation step of a polyprotic acid, when recorded. |
| pka3 | pKa₃ | number | Third dissociation step, when recorded. |
| values | Values | integer | Number of pKa statements in Wikidata (all steps). |
| pka_min | Lowest pKa | number | Lowest first-step pKa value in Wikidata. |
| pka_max | Highest pKa | number | Highest first-step pKa value in Wikidata. |
| pubchem_cid | PubChem CID | integer | — |
| cas_number | CAS number | string | — |
| wikipedia_languages | Wikipedia languages | integer | Number of Wikipedia language editions with an article — a rough measure of how well known the compound is. |
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