WebElements Periodic Table of the Elements | Actinium

Actinium: the essentials

Actinium is dangerously radioactive. The chemical behaviour of actinium is similar to that of the rare earths, particularly lanthanum. It is found naturally in uranium ores and actinium is 150 times more radioactive than radium.

Table: basic information about and classifications of actinium.
Name: Actinium Symbol: Ac Atomic number: 89 Atomic weight: [ 227 ] Standard state: solid at 298 K CAS Registry ID: 7440-34-8	Group in periodic table: Group name: Actinoid Period in periodic table: 7 (actinoid) Block in periodic table: f-block Colour: silvery Classification: Metallic

Actinium: historical information

Actinium was discovered by Andre Debierne at 1899 in France. Origin of name: from the Greek word "aktinos" meaning "ray".

Actinium was discovered by Andre Debierne in 1899 and independently by F. Giesel in 1902, both of whom obtained it while working on separation techniques for rare earth oxides.

Actinium: physical properties

Melting point: 1323 [or 1050 °C (1922 °F)] K
Boiling point: 3573 [or 3300 °C (5972 °F)] K
Density of solid: 10070 kg m^-3

Ground state electron configuration: [Rn].6d¹.7s²
Shell structure: 2.8.18.32.18.9.2
Term symbol: ²D_3/2
Pauling electronegativity: 1.1 (Pauling units)
First ionisation energy: 499 kJ mol^-1
Second ionisation energy: 1170 kJ mol^-1

Isolation

Isolation: coming soon!

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Ba	La	Ce
Ra	Ac	Th

Actinium	Actinium
Actinium	Actinium
Attinio	Actinio
Aktinium	Actínio

Actinium
- Essential data: names, symbol, atomic number, and atomic weight; block, period, and group in periodic table; description; standard state; registry number; and isolation
- History: meaning of name; discovery; and history of the element
- Uses
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Actinium around us
- Geology: Abundance of elements in the universe; the sun; meteorites; Earth's crust; oceans; and streams
- Biology: Abundance in humans; biological role; and health hazards)
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Chemistry and compounds
- Compounds: halides, oxides, sulfides, hydrides, and complexes; lattice energies; and reduction potentials
- Reactions of actinium: reactions of actinium with air; water; halogens; acids; and bases
- Electronegativities: Pauling; Sanderson; Allred Rochow; Mulliken-Jaffe; and Allen
- Bond enthalpies of diatomic species
- Lattice energies
Element properties
- Physics properties: Boiling point; melting point; density; molar volume; thermal conductivity; and electrical resistivity; bulk modulus; critical temperature; superconductivity temperature; hardness (mineralogical, Brinell, and Vickers); linear expansion coefficient; Poisson's ratio; reflectivity; refractive index; rigidity modulus; Young's modulus; velocity of sound
- Crystal structure
- Thermochemistry: enthalpies of atomization, fusion, and vaporization; thermodynamic properties
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Atom properties
- Electron shell properties: Electronic configuration; term symbol; electron affinity; ionization energies; and atomic spectra
- Atom sizes: atomic radius; Shannon and Pauling ionic radii; covalent radius; metallic radius; element bond length; and Van der Waals radius
- Atomic orbital properties: effective nuclear charge; electron binding energies; and valence orbital radii maxima
Nuclear properties
- Isotopes: isotope abundances; radioactive isotopes; isotope masses; nuclear spins; and nuclear magnetic moment
- NMR properties: frequencies; isotopes; magnetogyric ratios; quadrupole moments; receptivities; and relative sensitivities
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1	2															3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18

1 H																															2 He
3 Li	4 Be																									5 B	6 C	7 N	8 O	9 F	10 Ne
11 Na	12 Mg																									13 Al	14 Si	15 P	16 S	17 Cl	18 Ar
19 K	20 Ca															21 Sc	22 Ti	23 V	24 Cr	25 Mn	26 Fe	27 Co	28 Ni	29 Cu	30 Zn	31 Ga	32 Ge	33 As	34 Se	35 Br	36 Kr
37 Rb	38 Sr															39 Y	40 Zr	41 Nb	42 Mo	43 Tc	44 Ru	45 Rh	46 Pd	47 Ag	48 Cd	49 In	50 Sn	51 Sb	52 Te	53 I	54 Xe
55 Cs	56 Ba	57 La	58 Ce	59 Pr	60 Nd	61 Pm	62 Sm	63 Eu	64 Gd	65 Tb	66 Dy	67 Ho	68 Er	69 Tm	70 Yb	71 Lu	72 Hf	73 Ta	74 W	75 Re	76 Os	77 Ir	78 Pt	79 Au	80 Hg	81 Tl	82 Pb	83 Bi	84 Po	85 At	86 Rn
87 Fr	88 Ra	89 Ac	90 Th	91 Pa	92 U	93 Np	94 Pu	95 Am	96 Cm	97 Bk	98 Cf	99 Es	100 Fm	101 Md	102 No	103 Lr	104 Rf	105 Db	106 Sg	107 Bh	108 Hs	109 Mt	110 Ds	111 Rg	112 Cn	113 Uut	114 Fl	115 Uup	116 Lv	117 Uus	118 Uuo

Actinium

Actinium: the essentials

Actinium: historical information

Actinium: physical properties

Actinium: orbital properties

Isolation

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