Polonium - Po General Information Discovery Polonium was discovered in 1898 in Paris, France. It was the first element discovered by Marie Curie, while she was investigating the cause of radioactivity in pitchblende. Appearance Polonium is a silvery-grey, radioactive metal. Source Polonium is a very rare natural element. It is obtained when natural bismuth, 209Bi, is bombarded by neutrons to give 210Bi, the parent of polonium. Uses Polonium is an alpha-emitter, and is used as an alpha-particle source for scientific research in the form of a thin film on a stainless steel disc. It is also used as a heat source in space equipment. It can be mixed or alloyed with beryllium to provide a source of neutrons. Biological Role Polonium has no known biological role. It is highly toxic due to its radioactivity. General Information Polonium readily reacts with dilute acids, but only slightly with alkalis. A milligram of polonium emits as many alpha particles per second as 5 grams of radium. The energy released by its decay is so large that a capsule containing about 0.5 grams reaches a temperature above 500K.

	Physical Information
	Atomic Number		84
	Relative Atomic Mass (12C=12.000)		209 (radioactive)
	Melting Point/K		527
	Boiling Point/K		1235
	Density/kg m-3		9320 (293K)
	Ground State Electron Configuration		[Xe]4f145d106s26p4
	Electron Affinity(M-M-)/kJ mol-1		-186

	Key Isotopes
	nuclide	209Po	210Po	211Po	216Po	218Po
	atomic mass	208.98	209.98	210.99	216.0	218.0
	natural abundance	0%	trace	trace	trace	trace
	half-life	103 yrs	138.4 days	0.52 secs	0.15 secs	3.05 mins

Other Information
Enthalpy of Fusion/kJ mol-1		10
Enthalpy of Vaporisation/kJ mol-1		100.8
Oxidation States
main	Po+4
others	Po-2, Po+2, Po+6

	Ionisation Energies/kJ mol-1
	M - M+	812
	M+ - M2+	1800
	M2+ - M3+	2700
	M3+ - M4+	3700
	M4+ - M5+	5900
	M5+ - M6+	7000
	M6+ - M7+	10800
	M7+ - M8+	12700
	M8+ - M9+	14900
	M9+ - M10+	17000