Actinium

Actinium, ₀₀Ac
Actinium
Pronunciation	/ækˈtɪniəm/ (ak-TIN-ee-əm)
Appearance	silvery-white, glowing with an eerie blue light; sometimes with a golden cast
Mass number	[227]
Actinium in the periodic table
	radium ← actinium → thorium
Group	f-block groups (no number)
Period	period 7
Block	f-block
Electron configuration	[Rn] 6d1 7s2
Electrons per shell	2, 8, 18, 32, 18, 9, 2
Physical properties
Phase at STP	solid
Melting point	1500 K (1227 °C, 2240 °F) (estimated)
Boiling point	3500±300 K (3200±300 °C, 5800±500 °F) (extrapolated)
Density (near r.t.)	10 g/cm3
Heat of fusion	14 kJ/mol
Heat of vaporization	400 kJ/mol
Molar heat capacity	27.2 J/(mol·K)
Atomic properties
Oxidation states	+3 (a strongly basic oxide)
Electronegativity	Pauling scale: 1.1
Ionization energies	1st: 499 kJ/mol ; 2nd: 1170 kJ/mol ; 3rd: 1900 kJ/mol ; (more) ;
Covalent radius	215 pm
	Spectral lines of actinium
Other properties
Natural occurrence	from decay
Crystal structure	face-centered cubic (fcc)
Thermal conductivity	12 W/(m⋅K)
CAS Number	7440-34-8
History
Discovery and first isolation	Friedrich Oskar Giesel (1902)
Named by	André-Louis Debierne (1899)
Isotopes of actinium v; e;
14C	211Bi
ε	226Ra
α	222Fr
α	223Fr
	Category: Actinium; view; talk; edit; \| references

Actinium is chemical element 89 on the periodic table. Its symbol is Ac. Actinium's mass is 227 g/mol.

Actinium is a silver radioactive, solid metal in actinide group. It is so radioactive that it glows in the dark. Even a small amount of actinium is dangerous to people.

History

Actinium was discovered in 1899 by André-Louis Debierne, a French chemist. In 1899, Debierne described the substance as similar to titanium^[4] and (in 1900) as similar to thorium.^[5]

Properties

Actinium is a soft, silvery-white, radioactive metal.^[6]^[7] Its estimated shear modulus is similar to that of lead. Because its strong radioactivity, actinium glows in the dark with a pale blue light.^[8]

Actinium reacts quickly with oxygen and moisture in air forming a white coating of actinium oxide that stops the actinium from oxidizing.^[6]

Isotopes

Actinium that is found in nature is made up of two radionuclides ²²⁷Ac and ²²⁸Ac. Thirty-six radionuclides of actinium have been found. The most stable is ²²⁷Ac which has a half-life of 21.772 years. The shortest-lived known isotope of actinium is ²¹⁷Ac which has a half-life of 69 nanoseconds.

Occurence

Actinium is only found in trace amounts in uranium ores. For example, one tonne of uranium ore contains about 0.2 milligrams of ²²⁷Ac. Thorium ores contain about 5 nanograms of ²²⁸Ac per one tonne of thorium.^[9]

Uses

²²⁵Ac is now being studied for use in cancer treatments. ²²⁷Ac is studied for use as an active element of radioisotope thermoelectric generators. ²²⁵Ac is used in medicine to make ²¹³Bi in a reusable generator. It can be used in radiation therapy.^[10]^[11]^[12]

References

↑ Wall, Greg (8 September 2003). "C&EN: It's Elemental: The Periodic Table - Actinium". C&EN: It's Elemental: The Periodic Table. Chemical and Engineering News. Retrieved 2 June 2011.
↑ ^2.0 ^2.1 ^2.2 Kirby, Harold W.; Morss, Lester R. (2006). "Actinium". The Chemistry of the Actinide and Transactinide Elements. p. 18. doi:10.1007/1-4020-3598-5_2. ISBN 978-1-4020-3555-5.
↑ 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.
↑ Debierne, André-Louis (1899). "Sur un nouvelle matière radio-active". Comptes rendus (in French). 129: 593–595.
↑ Debierne, André-Louis (1900–1901). "Sur un nouvelle matière radio-actif – l'actinium". Comptes rendus (in French). 130: 906–908.
↑ ^6.0 ^6.1 Stites, Joseph G.; Salutsky, Murrell L.; Stone, Bob D. (1955). "Preparation of Actinium Metal 2". Journal of the American Chemical Society. 77 (1): 237–240. doi:10.1021/ja01606a085. ISSN 0002-7863.
↑ Solid state physics : advances in research and applications. Volume 16. Seitz, Frederick, 1911-2008., Turnbull, David, 1915-2007. New York: Academic Press. 1964. ISBN 978-0-08-086480-8. OCLC 646775097.{{cite book}}: CS1 maint: others (link)
↑ Katz, J J; Manning, W M (1952). "Chemistry of the Actinide Elements". Annual Review of Nuclear Science. 1 (1): 245–262. Bibcode:1952ARNPS...1..245K. doi:10.1146/annurev.ns.01.120152.001333. ISSN 0066-4243. Archived from the original on 2020-07-30. Retrieved 2020-10-15.
↑ Hagemann, French (1950). "The Isolation of Actinium 1". Journal of the American Chemical Society. 72 (2): 768–771. doi:10.1021/ja01158a033. ISSN 0002-7863.
↑ CRC handbook of chemistry and physics. Lide, David R., 1928- (86th ed., 2005-2006 ed.). Boca Raton: CRC Press. 2005. ISBN 0-8493-0486-5. OCLC 61108810.{{cite book}}: CS1 maint: others (link)
↑ Deblonde, Gauthier J.-P.; Abergel, Rebecca J. (2016). "Active actinium". Nature Chemistry. 8 (11): 1084. Bibcode:2016NatCh...8.1084D. doi:10.1038/nchem.2653. ISSN 1755-4330. PMID 27768109. S2CID 5404889.
↑ Boll, Rose A.; Malkemus, Dairin; Mirzadeh, Saed (2005). "Production of actinium-225 for alpha particle mediated radioimmunotherapy". Applied Radiation and Isotopes. 62 (5): 667–679. doi:10.1016/j.apradiso.2004.12.003. PMID 15763472.

[1] Wall, Greg (8 September 2003). "C&EN: It's Elemental: The Periodic Table - Actinium". C&EN: It's Elemental: The Periodic Table. Chemical and Engineering News. Retrieved 2 June 2011.

[Kirby-2] 2.0 ^2.1 ^2.2 Kirby, Harold W.; Morss, Lester R. (2006). "Actinium". The Chemistry of the Actinide and Transactinide Elements. p. 18. doi:10.1007/1-4020-3598-5_2. ISBN 978-1-4020-3555-5.

[NUBASE2020-3] 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.

[4] Debierne, André-Louis (1899). "Sur un nouvelle matière radio-active". Comptes rendus (in French). 129: 593–595.

[5] Debierne, André-Louis (1900–1901). "Sur un nouvelle matière radio-actif – l'actinium". Comptes rendus (in French). 130: 906–908.

[:0-6] 6.0 ^6.1 Stites, Joseph G.; Salutsky, Murrell L.; Stone, Bob D. (1955). "Preparation of Actinium Metal 2". Journal of the American Chemical Society. 77 (1): 237–240. doi:10.1021/ja01606a085. ISSN 0002-7863.

[7] Solid state physics : advances in research and applications. Volume 16. Seitz, Frederick, 1911-2008., Turnbull, David, 1915-2007. New York: Academic Press. 1964. ISBN 978-0-08-086480-8. OCLC 646775097.{{cite book}}: CS1 maint: others (link)

[8] Katz, J J; Manning, W M (1952). "Chemistry of the Actinide Elements". Annual Review of Nuclear Science. 1 (1): 245–262. Bibcode:1952ARNPS...1..245K. doi:10.1146/annurev.ns.01.120152.001333. ISSN 0066-4243. Archived from the original on 2020-07-30. Retrieved 2020-10-15.

[9] Hagemann, French (1950). "The Isolation of Actinium 1". Journal of the American Chemical Society. 72 (2): 768–771. doi:10.1021/ja01158a033. ISSN 0002-7863.

[10] CRC handbook of chemistry and physics. Lide, David R., 1928- (86th ed., 2005-2006 ed.). Boca Raton: CRC Press. 2005. ISBN 0-8493-0486-5. OCLC 61108810.{{cite book}}: CS1 maint: others (link)

[11] Deblonde, Gauthier J.-P.; Abergel, Rebecca J. (2016). "Active actinium". Nature Chemistry. 8 (11): 1084. Bibcode:2016NatCh...8.1084D. doi:10.1038/nchem.2653. ISSN 1755-4330. PMID 27768109. S2CID 5404889.

[12] Boll, Rose A.; Malkemus, Dairin; Mirzadeh, Saed (2005). "Production of actinium-225 for alpha particle mediated radioimmunotherapy". Applied Radiation and Isotopes. 62 (5): 667–679. doi:10.1016/j.apradiso.2004.12.003. PMID 15763472.

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