radium - actinium - thorium La Ac        Full table
General
Name, Symbol, Number	actinium, Ac, 89
Chemical series	Actinides
Group, Period, Block	3 , 7, f
Density, Hardness	10070 kg/m3, n/a
Appearance	silvery
Atomic properties
Atomic weight	(227) u
Atomic radius (calc.)	195 (n/a) pm
Covalent radius	n/a pm
van der Waals radius	n/a pm
Electron configuration	[Rn]6d17s2
e- 's per energy level	2, 8,18,32,18, 9, 2
Oxidation states (Oxide)	3 (neutral)
Crystal structure	face centered cubic
Physical properties
State of matter	solid (__)
Melting point	1323 K (1050 �C / 1922 �F)
Boiling point	3473 K (3200 �C / 5792 �F)
Molar volume	22.55 ×10-6 m3/mol
Heat of vaporization	n/a kJ/mol
Heat of fusion	62 kJ/mol
Vapor pressure	unknown Pa at 1323 K
Velocity of sound	unknown m/s at 293.15 K
Miscellaneous
Electronegativity	1.1 (Pauling scale)
Specific heat capacity	unknown J/(kg*K)
Electrical conductivity	unknown 106/m ohm
Thermal conductivity	12 W/(m*K)
1st ionization potential	499 kJ/mol
2nd ionization potential	1170 kJ/mol
3rd ionization potential	unknown kJ/mol
4th ionization potential	unknown kJ/mol
Most stable isotopes
iso NA half-life DM DE MeV DP 225Ac {syn.} 10 days α 5.935 221Fr 226Ac {syn.} 29.37 hours β- 1.117 226Th 226Ac {syn.} 29.37 hours e capture 0.640 226Ra 226Ac {syn.} 29.37 hours α 5.536 222Fr 227Ac 100 % 21.773 years β- 0.045 227Th 227Ac 100 % 21.773 years α 5.042 223Fr
SI units & STP are used except where noted.

Actinium is a chemical element in the periodic table that has the symbol Ac and atomic number 89.

Contents

1 Notable characteristics 2 Applications 3 History 4 Occurrence 5 Isotopes 6 Precautions 7 References 8 External links

Notable characteristics

Actinium is a silvery radioactive metallic element. Due to its intense radioactivity, Actinium glows in the dark with an eerie blue light. It is found only in traces in uranium ores as 227-Ac, an α and β emitter with a half-life of 21.773 years. One ton of uranium ore contains about a tenth of a gram of actinium.

Applications

It is about 150 times as radioactive as radium, making it valuable as a neutron source. Otherwise it has no significant industrial applications.

Actinium-225 is used in medicine to produce Bi-213 in a reusable generator or can be used alone as an agent for radio-immunotherapy.

History

Actinium was discovered in 1899 by Andr�-Louis Debierne, a French chemist, who separated it from pitchblende. Friedrich Otto Giesel independently discovered actinium in 1902. The chemical behavior of actinium is similar to that of the rare earth lanthanum.

The word actinium comes from the Greek aktis, aktinos, meaning beam or ray.

Occurrence

Actinium is found in trace amounts in uranium ore, but more commonly is made in milligram amounts by the neutron irradiation of 226-Ra in a nuclear reactor. Actinium metal has been prepared by the reduction of actinium fluoride with lithium vapor at about 1100 to 1300�C.

Isotopes

Naturally occurring actinium is composed of 1 radioactive isotope; with 227-Ac being the most abundant (100% natural abundance). 27 radioisotopes have been characterized with the most stable being 227-Ac with a half-life of 21.773 years, 225-Ac with a half-life of 10 days, and 226-Ac with a half-life of 29.37 hours. All of the remaining radioactive isotopes have half-lifes that are less than 10 hours and the majority of these have half lifes that are less than 1 minute. This element also has 2 meta states.

Purified actinium-227 comes into equilibrium with its decay products at the end of 185 days, and then decays according to its 21.773-year half-life.

The isotopes of actinium range in atomic weight from 206 u (206-actinium) to 234 u (234-actinium).

Precautions

Actinium-227 is extremely radioactive, and in terms of its potential for radiation induced health effects, actinium-227 is about as dangerous as plutonium. Ingesting even small amounts of actinium-227 would represent a serious health hazard.

References

• Los Alamos National Laboratory - Actinium (http://periodic.lanl.gov/elements/89.html)

it is cool

External links

• WebElements.com - Actinium (http://www.webelements.com/webelements/elements/text/Ac/index.html)
• EnvironmentalChemistry.com - Actinium (http://environmentalchemistry.com/yogi/periodic/Ac.html)

ca:Actini da:Actinium de:Actinium et:Aktiinium es:Actinio eo:Aktinio fr:Actinium it:Attinio la:Actinium nl:Actinium ja:アクチニウム no:Actinium pl:Aktyn pt:Act�nio sv:Aktinium