Polonium information

Polonium, ₈₄Po
Polonium
Pronunciation	/pəˈloʊniəm/ (pə-LOH-nee-əm)
Allotropes	α, β
Appearance	silvery
Mass number	[209]
Polonium in the periodic table
	bismuth ← polonium → astatine
Atomic number (Z)	84
Group	group 16 (chalcogens)
Period	period 6
Block	p-block
Electron configuration	[Xe] 4f14 5d10 6s2 6p4
Electrons per shell	2, 8, 18, 32, 18, 6
Physical properties
Phase at STP	solid
Melting point	527 K (254 °C, 489 °F)
Boiling point	1235 K (962 °C, 1764 °F)
Density (near r.t.)	α-Po: 9.196 g/cm3 ; β-Po: 9.398 g/cm3
Heat of fusion	ca. 13 kJ/mol
Heat of vaporization	102.91 kJ/mol
Molar heat capacity	26.4 J/(mol·K)
Atomic properties
Oxidation states	−2, +2, +4, +5, +6 (an amphoteric oxide)
Electronegativity	Pauling scale: 2.0
Ionization energies	1st: 812.1 kJ/mol ; ;
Atomic radius	empirical: 168 pm
Covalent radius	140±4 pm
Van der Waals radius	197 pm
	Spectral lines of polonium
Other properties
Natural occurrence	from decay
Crystal structure	cubic ; α-Po
Crystal structure	rhombohedral ; β-Po
Thermal expansion	23.5 µm/(m⋅K) (at 25 °C)
Thermal conductivity	20 W/(m⋅K) (?)
Electrical resistivity	α-Po: 0.40 µΩ⋅m (at 0 °C)
Magnetic ordering	nonmagnetic
CAS Number	7440-08-6
History
Naming	after Polonia, Latin for Poland, homeland of Marie Curie
Discovery	Pierre and Marie Curie (1898)
First isolation	Willy Marckwald (1902)
Isotopes of polonium v; e;
β+	208Bi
β+	209Bi
	Category: Polonium; view; talk; edit; \| references

Polonium is a chemical element; it has symbol Po and atomic number 84. A rare and highly radioactive metal (although sometimes classified as a metalloid) with no stable isotopes, polonium is a chalcogen and chemically similar to selenium and tellurium, though its metallic character resembles that of its horizontal neighbors in the periodic table: thallium, lead, and bismuth. Due to the short half-life of all its isotopes, its natural occurrence is limited to tiny traces of the fleeting polonium-210 (with a half-life of 138 days) in uranium ores, as it is the penultimate daughter of natural uranium-238. Though longer-lived isotopes exist, such as the 124 years half-life of polonium-209, they are much more difficult to produce. Today, polonium is usually produced in milligram quantities by the neutron irradiation of bismuth. Due to its intense radioactivity, which results in the radiolysis of chemical bonds and radioactive self-heating, its chemistry has mostly been investigated on the trace scale only.

Polonium was discovered on July 18, 1898 by Marie Skłodowska-Curie and Pierre Curie, when it was extracted from the uranium ore pitchblende^[3] and identified solely by its strong radioactivity: it was the first element to be so discovered. Polonium was named after Marie Curie's homeland of Poland. Polonium has few applications, and those are related to its radioactivity: heaters in space probes, antistatic devices, sources of neutrons and alpha particles, and poison e.g. poisoning of Alexander Litvinenko. It is extremely dangerous to humans.

^ Thayer, John S. (2010). "Relativistic Effects and the Chemistry of the Heavier Main Group Elements". Relativistic Methods for Chemists. Challenges and Advances in Computational Chemistry and Physics. 10: 78. doi:10.1007/978-1-4020-9975-5_2. ISBN 978-1-4020-9974-8.
^ Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S.; Audi, G. (2021). "The NUBASE2020 evaluation of nuclear properties" (PDF). Chinese Physics C. 45 (3): 030001. doi:10.1088/1674-1137/abddae.
^ "Polonium (Po) | AMERICAN ELEMENTS ®". American Elements: The Materials Science Company. Retrieved 17 April 2024.

[Thayer_p78-1] Thayer, John S. (2010). "Relativistic Effects and the Chemistry of the Heavier Main Group Elements". Relativistic Methods for Chemists. Challenges and Advances in Computational Chemistry and Physics. 10: 78. doi:10.1007/978-1-4020-9975-5_2. ISBN 978-1-4020-9974-8.

[NUBASE2020-2] Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S.; Audi, G. (2021). "The NUBASE2020 evaluation of nuclear properties" (PDF). Chinese Physics C. 45 (3): 030001. doi:10.1088/1674-1137/abddae.

[3] "Polonium (Po) | AMERICAN ELEMENTS ®". American Elements: The Materials Science Company. Retrieved 17 April 2024.

Polonium information

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