89 radium ← actinium → thorium La ↑ Ac ↓ Ute Periodic Table - Extended Periodic Table
General
Name, Symbol, Number	actinium, Ac, 89
Chemical series	actinides
Group, Period, Block	3, 7, f
Appearance	silvery
Standard atomic weight	(227) g·mol−1
Electron configuration	[Rn] 6d1 7s2
Electrons per shell	2, 8, 18, 32, 18, 9, 2
Physical properties
Phase	solid
Density (near r.t.)	10 g·cm−3
Melting point	(circa) 1323 K (1050 °C, 1922 °F)
Boiling point	3471 K (3198 °C, 5788 °F)
Heat of fusion	14 kJ·mol−1
Heat of vaporization	400 kJ·mol−1
Heat capacity	(25 °C) 27.2 J·mol−1·K−1
Atomic properties
Crystal structure	cubic face centered
Oxidation states	3 (neutral oxide)
Electronegativity	1.1 (scale Pauling)
Ionization energies	1st: 499 kJ/mol
	2nd: 1170 kJ/mol
Atomic radius	195 pm
Miscellaneous
Magnetic ordering	no data
Thermal conductivity	(300 K) 12 W·m−1·K−1
CAS registry number	7440-34-8
Selected isotopes
Main article: Isotopes of actinium 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 ε 0.640 226Ra α 5.536 222Fr 227Ac 100% 21.773 years β- 0.045 227Th α 5.042 223Fr
References

Actinium (pronounced /ækˈtɪniəm/) is a chemical element in the periodic table that has the symbol Ac and atomic number 89. General Name, Symbol, Number radium, Ra, 88 Chemical series alkaline earth metals Group, Period, Block 2, 7, s Appearance silvery white metallic Standard atomic weight (226) g·mol−1 Electron configuration [Rn] 7s2 Electrons per shell 2, 8, 18, 32, 18, 8, 2 Physical properties Phase solid Density (near r. ... General Name, Symbol, Number thorium, Th, 90 Chemical series Actinides Group, Period, Block n/a, 7, f Appearance silvery white Standard atomic weight 232. ... General Name, Symbol, Number lanthanum, La, 57 Chemical series lanthanides Group, Period, Block 3, 6, f Appearance silvery white Atomic mass 138. ... General Name, Symbol, Number untriennium, Ute, 139 Chemical series Superactinides Group, Period, Block 3, 8, f Appearance  ? Standard atomic weight [370] amu (supposition) g·mol−1 Electron configuration [Uuo] 5g18 6f1 8s2 Electrons per shell 2, 8, 18, 32, 50, 19, 8, 2 Physical properties Phase presumably solid Miscellaneous Selected... Image File history File links By Greatpatton. ... This is a standard display of the periodic table of the elements. ... An extended periodic table was suggested by Glenn T. Seaborg in 1969. ... This is a list of chemical elements, sorted by name and color coded according to type of element. ... A table of chemical elements ordered by atomic number and color coded according to type of element. ... A group, also known as a family, is a vertical column in the periodic table of the chemical elements. ... The actinide (or actinoid) series encompasses the 15 chemical elements that lie between actinium and lawrencium on the periodic table, with atomic numbers 89 - 103[1]. The actinide series is named after actinium. ... A group, also known as a family, is a vertical column in the periodic table of the chemical elements. ... In the periodic table of the elements, a period is a horizontal row of the table. ... A block of the periodic table of elements is a set of adjacent groups. ... A Group 3 element is an element in periodic table group 3 (IUPAC style) in the periodic table, which consists of: scandium (21) yttrium (39) lanthanum (57) - lutetium (71) actinium (89) - lawrencium (103) All of these elements are classed in Group 3 because their outer shell holds three electrons. ... A period 7 element is one of the chemical elements in the seventh row (or period) of the periodic table of the elements. ... The f-block of the periodic table of elements consists of those elements for which, in the atomic ground state, the highest-energy electrons occupy f-orbitals. ... Color is an important part of the visual arts. ... The atomic mass (ma) is the mass of an atom at rest, most often expressed in unified atomic mass units. ... To help compare different orders of magnitude we list here masses between 60. ... Electron atomic and molecular orbitals In atomic physics and quantum chemistry, the electron configuration is the arrangement of electrons in an atom, molecule, or other physical structure (, a crystal). ... For other uses, see Radon (disambiguation). ... For other uses, see Electron (disambiguation). ... Example of a sodium electron shell model An electron shell, also known as a main energy level, is a group of atomic orbitals with the same value of the principal quantum number n. ... In the physical sciences, a phase is a set of states of a macroscopic physical system that have relatively uniform chemical composition and physical properties (i. ... For other uses, see Solid (disambiguation). ... For other uses, see Density (disambiguation). ... For other uses, see Room temperature (disambiguation). ... The melting point of a crystalline solid is the temperature range at which it changes state from solid to liquid. ... For other uses, see Kelvin (disambiguation). ... Celsius is, or relates to, the Celsius temperature scale (previously known as the centigrade scale). ... For other uses, see Fahrenheit (disambiguation). ... Italic text This article is about the boiling point of liquids. ... For other uses, see Kelvin (disambiguation). ... Celsius is, or relates to, the Celsius temperature scale (previously known as the centigrade scale). ... For other uses, see Fahrenheit (disambiguation). ... Standard enthalpy change of fusion of period three. ... The joule per mole (symbol: J·mol-1) is an SI derived unit of energy per amount of material. ... The standard enthalpy change of vaporization, ΔvHo, also (less correctly) known as the heat of vaporization is the energy required to transform a given quantity of a substance into a gas. ... The joule per mole (symbol: J·mol-1) is an SI derived unit of energy per amount of material. ... To meet Wikipedias quality standards, this article or section may require cleanup. ... Enargite crystals In mineralogy and crystallography, a crystal structure is a unique arrangement of atoms in a crystal. ... The oxidation number of an element in a molecule or complex is the charge that it would have if all the ligands (basically, atoms that donate electrons) were removed along with the electron pairs that were shared with the central atom[1]. It means that the oxidation number is the... Electronegativity is a measure of the ability of an atom or molecule to attract electrons in the context of a chemical bond. ... The ionization potential, ionization energy or EI of an atom or molecule is the energy required to remove one mole of electrons from one mole of isolated gaseous atoms or ions. ... The joule per mole (symbol: J·mol-1) is an SI derived unit of energy per amount of material. ... Atomic radius: Ionic radius Covalent radius Metallic radius van der Waals radius edit Atomic radius, and more generally the size of an atom, is not a precisely defined physical quantity, nor is it constant in all circumstances. ... You have big harry skanky balls ... One picometre is defined as 1x10-12 metres, in standard units. ... For other senses of this word, see magnetism (disambiguation). ... K value redirects here. ... CAS registry numbers are unique numerical identifiers for chemical compounds, polymers, biological sequences, mixtures and alloys. ... Actinium (Ac) Has no stable isotopes. ... For other uses, see Isotope (disambiguation). ... Natural abundance refers to the prevalence of different isotopes of an element as found in nature. ... Half-Life For a quantity subject to exponential decay, the half-life is the time required for the quantity to fall to half of its initial value. ... Radioactive decay is the process in which an unstable atomic nucleus loses energy by emitting radiation in the form of particles or electromagnetic waves. ... The decay energy is the energy released by a nuclear decay. ... The electronvolt (symbol eV) is a unit of energy. ... In nuclear physics, a decay product, also known as a daughter product, is a nuclide resulting from the radioactive decay of a parent or precursor nuclide. ... A Synthetic radioisotope is a radionuclide that is not found in nature: no natural process or mechanism exists which produces it, or it is so unstable that it decays away in a very short period of time. ... (Redirected from 1 E s) An order of magnitude is the class of scale or magnitude of any amount, where each class contains values of a fixed ratio to the class preceding it. ... Alpha decay Alpha decay is a type of radioactive decay in which an atom emits an alpha particle (two protons and two neutrons bound together into a particle identical to a helium nucleus) and transforms (or decays) into an atom with a mass number 4 less and atomic number 2... General Name, Symbol, Number francium, Fr, 87 Chemical series alkali metals Group, Period, Block 1, 7, s Appearance metallic Atomic mass (223) g·mol−1 Electron configuration [Rn] 7s1 Electrons per shell 2, 8, 18, 32, 18, 8, 1 Physical properties Phase solid Density (near r. ... A Synthetic radioisotope is a radionuclide that is not found in nature: no natural process or mechanism exists which produces it, or it is so unstable that it decays away in a very short period of time. ... (Redirected from 1 E s) An order of magnitude is the class of scale or magnitude of any amount, where each class contains values of a fixed ratio to the class preceding it. ... In nuclear physics, beta decay (sometimes called neutron decay) is a type of radioactive decay in which a beta particle (an electron or a positron) is emitted. ... General Name, Symbol, Number thorium, Th, 90 Chemical series Actinides Group, Period, Block n/a, 7, f Appearance silvery white Standard atomic weight 232. ... Electron capture is a decay mode for isotopes that will occur when there are too many protons in the nucleus of an atom, and there isnt enough energy to emit a positron; however, it continues to be a viable decay mode for radioactive isotopes that can decay by positron... General Name, Symbol, Number radium, Ra, 88 Chemical series alkaline earth metals Group, Period, Block 2, 7, s Appearance silvery white metallic Standard atomic weight (226) g·mol−1 Electron configuration [Rn] 7s2 Electrons per shell 2, 8, 18, 32, 18, 8, 2 Physical properties Phase solid Density (near r. ... Alpha decay Alpha decay is a type of radioactive decay in which an atom emits an alpha particle (two protons and two neutrons bound together into a particle identical to a helium nucleus) and transforms (or decays) into an atom with a mass number 4 less and atomic number 2... General Name, Symbol, Number francium, Fr, 87 Chemical series alkali metals Group, Period, Block 1, 7, s Appearance metallic Atomic mass (223) g·mol−1 Electron configuration [Rn] 7s1 Electrons per shell 2, 8, 18, 32, 18, 8, 1 Physical properties Phase solid Density (near r. ... (Redirected from 1 E s) An order of magnitude is the class of scale or magnitude of any amount, where each class contains values of a fixed ratio to the class preceding it. ... In nuclear physics, beta decay (sometimes called neutron decay) is a type of radioactive decay in which a beta particle (an electron or a positron) is emitted. ... General Name, Symbol, Number thorium, Th, 90 Chemical series Actinides Group, Period, Block n/a, 7, f Appearance silvery white Standard atomic weight 232. ... Alpha decay Alpha decay is a type of radioactive decay in which an atom emits an alpha particle (two protons and two neutrons bound together into a particle identical to a helium nucleus) and transforms (or decays) into an atom with a mass number 4 less and atomic number 2... General Name, Symbol, Number francium, Fr, 87 Chemical series alkali metals Group, Period, Block 1, 7, s Appearance metallic Atomic mass (223) g·mol−1 Electron configuration [Rn] 7s1 Electrons per shell 2, 8, 18, 32, 18, 8, 1 Physical properties Phase solid Density (near r. ... Recommended values for many properties of the elements, together with various references, are collected on these data pages. ... The periodic table of the chemical elements A chemical element, or element, is a type of atom that is defined by its atomic number; that is, by the number of protons in its nucleus. ... The Periodic Table redirects here. ... See also: List of elements by atomic number In chemistry and physics, the atomic number (also known as the proton number) is the number of protons found in the nucleus of an atom. ...

Notable characteristics

Actinium is a silvery, radioactive, metallic element. Due to its intense radioactivity, Actinium glows in the dark with a pale blue light. It is found only in traces in uranium ores as ²²⁷Ac, 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. Radioactive decay is the set of various processes by which unstable atomic nuclei (nuclides) emit subatomic particles. ... An alpha particle is deflected by a magnetic field Alpha particles or alpha rays are a form of particle radiation which are highly ionizing and have low penetration. ... Beta particles are high-energy electrons emitted by certain types of radioactive nuclei such as potassium-40. ... Half-Life For a quantity subject to exponential decay, the half-life is the time required for the quantity to fall to half of its initial value. ... General Name, symbol, number uranium, U, 92 Chemical series actinides Group, period, block n/a, 7, f Appearance silvery gray metallic; corrodes to a spalling black oxide coat in air Standard atomic weight 238. ...

Applications

It is about 150 times as radioactive as radium, making it valuable as a neutron source. Otherwise it has no significant industrial applications. A neutron source is a device, used in solid state physics (see neutron diffraction), particle physics and to start nuclear chain reactions, that emits neutrons. ...

²²⁵Ac is used in medicine to produce ²¹³Bi in a reusable generator or can be used alone as an agent for radio-immunotherapy for Targeted Alpha Therapy (TAT). ²²⁵Ac was first produced artificially by the ITU in Germany using a cyclotron and by Dr Graeme Melville at St George Hospital in Sydney using a linac in 2000. General Name, Symbol, Number bismuth, Bi, 83 Chemical series poor metals Group, Period, Block 15, 6, p Appearance lustrous reddish white Atomic mass 208. ...

History

Actinium was discovered in 1899 by André-Louis Debierne, a French chemist, who separated it from pitchblende. Friedrich Oskar Giesel independently discovered actinium in 1902 and called it "emanium" in 1904. Debierne's name was retained because it had seniority. The chemical behavior of actinium is similar to that of the rare earth lanthanum. Year 1899 (MDCCCXCIX) was a common year starting on Sunday (link will display the full calendar) of the Gregorian calendar (or a common year starting on Friday [1] of the 12-day-slower Julian calendar). ... André-Louis Debierne (1874 - August, 1949) was a French chemist, born in Paris. ... For the band, see Pitchblende (band). ... Year 1902 (MCMII) was a common year starting on Wednesday (link will display calendar) of the Gregorian calendar (or a common year starting on Tuesday [1] of the 13-day-slower Julian calendar). ... General Name, Symbol, Number lanthanum, La, 57 Chemical series lanthanides Group, Period, Block 3, 6, f Appearance silvery white Atomic mass 138. ...

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 amountsreactor. Actinium metal has been prepared by the reduction of actinium fluoride with lithium vapor at about 1100 to 1300ºC. Uraninite is a uranium-rich mineral with a composition that is largely UO2 (uranium oxide), but which also contains UO3 and oxides of lead, thorium, and rare earths. ...

Isotopes

Main article: isotopes of actinium

Naturally occurring actinium is composed of 1 radioactive isotope; ²²⁷Ac. 36 radioisotopes have been characterized with the most stable being ²²⁷Ac with a half-life of 21.772 y, ²²⁵Ac with a half-life of 10.0 days, and ²²⁶Ac with a half-life of 29.37 h. 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. The shortest-lived isotope of actinium is ²¹⁷Ac which decays through alpha decay and electron capture. It has a half-life of 69 ns. Actinium also has 2 meta states. Actinium (Ac) Has no stable isotopes. ... For other uses, see Isotope (disambiguation). ... A radionuclide is an atom with an unstable nucleus. ... Half-Life For a quantity subject to exponential decay, the half-life is the time required for the quantity to fall to half of its initial value. ... A year (from Old English gÄ“r) is the time between two recurrences of an event related to the orbit of the Earth around the Sun. ... Look up day in Wiktionary, the free dictionary. ... The hour (symbol: h) is a unit of time. ... Radioactive decay is the process in which an unstable atomic nucleus loses energy by emitting radiation in the form of particles or electromagnetic waves. ... Alpha decay Alpha decay is a type of radioactive decay in which an atom emits an alpha particle (two protons and two neutrons bound together into a particle identical to a helium nucleus) and transforms (or decays) into an atom with a mass number 4 less and atomic number 2... Electron capture is a decay mode for isotopes that will occur when there are too many protons in the nucleus of an atom, and there isnt enough energy to emit a positron; however, it continues to be a viable decay mode for radioactive isotopes that can decay by positron... A nanosecond is an SI derived unit of time equal to 10-9 of a second. ... A nuclear isomer is a metastable state of an atom caused by the excitation of a proton or neutron in its nucleus so that it requires a change in spin before it can release its extra energy. ...

Purified ²²⁷Ac 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 (²⁰⁶Ac) to 236 u (²³⁶Ac). ... The unified atomic mass unit (u), or dalton (Da), is a small unit of mass used to express atomic and molecular masses. ...

Precautions

²²⁷Ac is extremely radioactive, and in terms of its potential for radiation induced health effects, ²²⁷Ac is even more dangerous than plutonium. Ingesting even small amounts of ²²⁷Ac would kill that person. General Name, Symbol, Number plutonium, Pu, 94 Chemical series actinides Group, Period, Block n/a, 7, f Appearance silvery white Standard atomic weight (244) g·mol−1 Electron configuration [Rn] 5f6 7s2 Electrons per shell 2, 8, 18, 32, 24, 8, 2 Physical properties Phase solid Density (near r. ...

References

• Los Alamos National Laboratory - Actinium

External links

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• WebElements.com - Actinium
• NLM Hazardous Substances Databank – Actinium, Radioactive