Radioactive metal m.p. 254 ºC; 489 ºF b.p. 962 ºC; 1764 ºF density (α modification) 9.32 g/cc; 581.83 pound/cubic foot	memory peg
	1898 Pierre & Marie Curie, France
	Polonia = Polska Poland (Latin)

In 1898 Pierre Curie (1859-1906) and Marie Curie née Sklodowska (1867-1934) investigated pitchblende from Bohemia, containing to 75% Uranium, and noted that the tar possesses considerably higher radioactivity, than the isolated uranium. So they assumed that it contained one or more new elements of high radioactivity. In July 1898 they made a complete analysis of the pitchblende, which proved to be very complex, since several elements were contained. Two fractions had increased radioactivity: one of them contained salts of Bismuth, another Barium salts. From the Bismuth fraction they isolated a product with a radioactivity 400 times superior to that of Uranium. Thus they conclued that this activity was caused by the presence of salts of some so far unknown metal. They named it Polonium in honor of Marie's native land (Lat. Polonia - Polska). In their laboratory journal the symbol Po (written by Pierre) appears for the first time on 13 July 1898. (note).

Later the existence of Polonium was considered questionable. Polonium was thought to be a radioactive form if Bismuth, and Friedrich O. Giesel called it Radiobismuth ("Radiowismuth", 1899) (note) . In 1902 Willy Marckwald (1864-) verified the analysis of pitchblende with a large quantity of mineral (about 2 tons). He isolated the Bismuth fraction and detected a new element in it, which he named Radiotellurium, since it was strongly radioactive and has properties similar to Tellurium. Salt of Radiotellurium was millions of times more active than Uranium and 1000 times more than Polonium. Already in 1889 Д.И. Менделеев (D.I. Mendeleyev) predicted the existence of an element with such properties and on his assumed position in the periodic system was named Dvi-tellurium (Dt).

Ernest Rutherford (1871-1937) established later that Radiotellurium is one of the radioactive decay products of the Uranium family, and had it named Radium-F. In 1905 it became obvious, that Polonium, Radiotellurium and Radium-F are one and the same element, possessing alfa- and gamma/range - by emission and having a half-life period of approximately 140 days.

As a result was acknowledged that the priority of the discovery of the new element belonged to the Curies, and was it finally given the name she proposed.

Historical names of Polonium isotopes

Name & Symbol (hist. and modern)			First described		Notes
Radium-A	Ra A	218Po	1905	William H. Bragg & Richard D. Kleeman
Thorium-A	Th A	216Po	1910/11	Hans W. Geiger, Ernest Marsden & Ernest Rutherford	Earlier ThA renamed ThB
Actinium-A	Ac A	215Po	1910/11	Hans W. Geiger & Ernest Marsden	Earlier AcA renamed AcB
Radium-C'	Ra C'	214Po	1909 1912	Otto Hahn & Lise Meitner Kasimir Fajans
Thorium-C'	Th C'	212Po	1906	Otto Hahn	Originally Thorium-C
Actinium-C'	Ac C'	211Po	1913	Ernest Marsden & R.H. Wilson
Radium-F Radiotellurium	Ra F Rd Te	210Po	1902	Willy Marckwald

Further reading:

• Mary Elvira Weeks, Discovery of the Elements, comp. rev. by Heny M. Leicester (Easton, Pa.: Journal of Chemical Education, 1968), pp. 778-781.
• Polonium und Isotope. Gmelins Handbuch der anorganische Chemie, 8. Aufl.; System-Nummer 12 (1941).