# protactinium

> element with symbol Pa and atomic number of 91

**Wikidata**: [Q1109](https://www.wikidata.org/wiki/Q1109)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/Protactinium)  
**Source**: https://4ort.xyz/entity/protactinium


## References

1. protactinium. Global Substance Registration System
2. [CAS Common Chemistry](https://commonchemistry.cas.org/detail?cas_rn=7440-13-3)
3. Protactinium. ECHA Substance Infocard database
4. PROTACTINIUM. PubChem
5. ChEBI release 2020-09-01
6. Atomic weights of the elements 2009 (IUPAC Technical Report)
7. [Source](https://lingualibre.org/wiki//Q379882)
8. [Source](https://www.cns11643.gov.tw/wordView.jsp?ID=158275)
9. Freebase Data Dumps. 2013
10. Protactinium. ChemSpider
11. protactinium atom. ChEBI
12. Characterization of steroidal glycosides from the extract of Paris Polyphylla var. Yunnanensis by UPLC/Q-TOF MSE.
13. Standard Atomic Weights of 14 Chemical Elements Revised (English). Chemistry International
14. UMLS 2023
15. Mapping file of InChIStrings, InChIKeys and DTXSIDs for the EPA CompTox Dashboard
16. CABI Thesaurus
17. National Library of Israel
18. KBpedia
19. GF WordNet
20. [OpenAlex](https://docs.openalex.org/download-snapshot/snapshot-data-format)
21. UniChem