In the following table, the use row is the value recommended for use in other Wikipedia pages in order to maintain consistency across content.
Primordial From decay Synthetic Border shows natural occurrence of the element
Zhang, Yiming; Evans, Julian R. G.; Yang, Shoufeng (2011). "Corrected Values for Boiling Points and Enthalpies of Vaporization of Elements in Handbooks". J. Chem. Eng. Data. 56 (2): 328–337. doi:10.1021/je1011086.
As quoted at http://www.webelements.com/ from these sources:
As quoted from:
Otozai, K.; Takahashi, N. (1982). "Estimation Chemical Form Boiling Point Elementary Astatine by Radio Gas Chromatography". Radiochimica Acta. 31 (3–4): 201–203. doi:10.1524/ract.1982.31.34.201. S2CID 100363889.
Lavrukhina, Avgusta Konstantinovna; Pozdnyakov, Aleksandr Aleksandrovich (1970). Analytical Chemistry of Technetium, Promethium, Astatine, and Francium. Translated by R. Kondor. Ann Arbor–Humphrey Science Publishers. p. 269. ISBN 978-0-250-39923-9.