# Aktinido

Tumalon sa: nabigasyon, hanapin
Mga Aktinido sa talaang peryodiko

Ang aktinido o ang seryeng actinoid (nomenklaturang IUPAC) ay binubuo ng labinlimang metalikong elementong kemikal na may mga atomikong bilang mula 89 hanggang 103, aktinyo hanggang lawrensyo.[2][3][4][5]

Nagmula ang pangalan ng seryeng aktinido mula sa isang elemento ng ikatlong elementong pangkat, ang aktinyo. Lahat, maliban sa isa, ng mga lantanido ay mga elementong nasa f-bloke, na sumusunod sa pagpupuno ng talukab ng elektron sa 4f; lawrensyo, isang elementong d-bloke, ay kadalasang isinasama sa pangkat ng aktinido. Kung ihahambing sa mga lantanido, na karamihan din ay mga elementong f-bloke, nagpapakita naman ng mas pabago-bagong balensiya ang mga aktinido.

 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

Of the actinides, primordial thorium and uranium occur naturally in substantial quantities and small amounts of persisting natural plutonium have also been identified. The radioactive decay of uranium produces transient amounts of actinium and protactinium, and atoms of neptunium, americium, curium, berkelium and californium are occasionally produced from transmutation reactions in uranium ores. The other actinides are purely synthetic elements.[2][6] Nuclear weapons tests have released at least six actinides heavier than plutonium into the environment; analysis of debris from a 1952 hydrogen bomb explosion showed the presence of americium, curium, berkelium, californium, einsteinium and fermium.[7]

All actinides are radioactive and release energy upon radioactive decay; naturally occurring uranium and thorium, and synthetically produced plutonium are the most abundant actinides on Earth. These are used in nuclear reactors and nuclear weapons. Uranium and thorium also have diverse current or historical uses, and americium is used in the ionization chambers of most modern smoke detectors.

In presentations of the periodic table, the lanthanides and the actinides are customarily shown as two additional rows below the main body of the table,[2] with placeholders or else a selected single element of each series (either lanthanum or lutetium, and either actinium or lawrencium, respectively) shown in a single cell of the main table, between barium and hafnium, and radium and rutherfordium, respectively. This convention is entirely a matter of aesthetics and formatting practicality; a rarely used wide-formatted periodic table inserts the lanthanide and actinide series in their proper places, as parts of the table's sixth and seventh rows (periods).

## Katangian

Actinides have similar properties to lanthanides. The 6d and 7s electronic shells are filled in actinium and thorium, and the 5f shell is being filled with further increase in atomic number; the 4f shell is filled in the lanthanides. The first experimental evidence for the filling of the 5f shell in actinides was obtained by McMillan and Abelson in 1940.[8] As in lanthanides (see lanthanide contraction), the ionic radius of actinides monotonically decreases with atomic number (see also Aufbau principle).[9]

Property Core charge atomic mass Number of natural isotopes[12] Natural isotopes[12][13] Longest-lived isotope Half-life of the longest-lived isotope Electronic configuration in the ground state Oxidation state Metallic radius, nm Ionic radius, nm: Temperature, °C: Density, g/cm3 Standard electrode potential, V: Color An4+ melting E° (An4+/An0) [M(H2O)n]4+ An3+ boiling E° (An3+/An0) [M(H2O)n]3+ Ac Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 [227] 232.0381 231.03588 238.02891 [237] [244] [243] [247] [247] [251] [252] [257] [258] [259] [262] 3 9 5 9 4 5 5 8 2 5 — — — — — 225, 227–228 226–232, 234–235 231, 233–236 232–240 237–240 238–240, 242, 244 241–245 242–249 249–250 249–253 — — — — — 227 232 231 238 237 244 243 247 247 251 252 257 258 259 262 21.8 years 14 billion years 32,500 years 4.47 billion years 2.14 million years 80.8 million years 7,370 years 15.6 million years 1,400 years 900 years 1.29 years 100.5 days 52 days 58 min 261 min 6d17s2 6d27s2 5f26d17s2or 5f16d27s2 5f36d17s2 5f46d17s2or 5f57s2 5f67s2 5f77s2 5f76d17s2 5f97s2or 5f86d17s2 5f107s2 5f117s2 5f127s2 5f137s2 5f147s2 5f147s27p1 3 3, 4 3, 4, 5 3, 4, 5, 6 3, 4, 5, 6, 7 3, 4, 5, 6, 7 2, 3, 4 3, 4 3, 4 2, 3 2, 3 2, 3 2, 3 2, 3 3 0.203 0.180 0.162 0.153 0.150 0.162 0.173 0.174 0.170 0.186 0.186 — — — — — 0.126 0.114 — 0.104 0.118 0.103 0.118 0.101 0.116 0.100 0.115 0.099 0.114 0.099 0.112 0.097 0.110 0.096 0.109 0.085 0.098 0.084 0.091 0.084 0.090 0.084 0.095 0.083 0.088 1050 3300 1750 4800 1572 4400 1130 3800 640 3900 640 3230 1176 2610 1340 — 1050 — 900 — 860 — 1530 — 830 — 830 — 1630 — 10.07 11.78 15.37 19.06 20.25 19.84 11.7 13.51 14.78 — −2.13 −1.83 — −1.47 — −1.38 −1.66 −1.30 −1.79 −1.25 −2.00 −0.90 −2.07 −0.75 −2.06 −0.55 −1.96 −0.59 −1.97 −0.36 −1.98 −0.29 −1.96 — −1.74 — −1.20 - −2.10 — Colorless Colorless Blue Yellow Dark blue Green Purple Yellow-green Purple Brown Violet Red Rose Yellow Colorless Beige Yellow-green Green Green — Pink — — — — — — — —

### Pisikal na katangian

 400px Major crystal structures of some actinides vs. temperature Metallic and ionic radii of actinides[11]
A pellet of 238PuO2 to be used in a radioisotope thermoelectric generator for either the Cassini or Galileo mission. The pellet produces 62 watts of heat and glows because of the heat generated by the radioactive decay (primarily α). Photo is taken after insulating the pellet under a graphite blanket for minutes and removing the blanket.
Californium

Actinides are typical metals. All of them are soft and have a silvery color (but tarnish in air),[15] relatively high density and plasticity. Some of them can be cut with a knife. Their electrical resistivity varies between 15 and 150 µOhm·cm.[11] The hardness of thorium is similar to that of soft steel, so heated pure thorium can be rolled in sheets and pulled into wire. Thorium is nearly half as dense as uranium and plutonium, but is harder than either of them. All actinides are radioactive, paramagnetic, and, with the exception of actinium, have several crystalline phases: plutonium has seven, and uranium, neptunium and californium three. Crystal structures of protactinium, uranium, neptunium and plutonium do not have clear analogs among the lanthanides and are more similar to those of the 3d-transition metals.[10]

All actinides are pyrophoric, especially when finely divided, that is, they spontaneously ignite upon reaction with air.[15] The melting point of actinides does not have a clear dependence on the number of f-electrons. The unusually low melting point of neptunium and plutonium (~640 °C) is explained by hybridization of 5f and 6d orbitals and the formation of directional bonds in these metals.[10]

## Kompuwesto

### Oksido at and hidroksido

An – actinide
**Depending on the isotopes

Some actinides can exists in several oxide forms such as An2O3, AnO2, An2O5 and AnO3. For all actinides, oxides AnO3 are amphoteric and An2O3, AnO2 and An2O5 are basic, they easily react with water, forming bases:[26]

An2O3 + 3 H2O → 2 An(OH)3.

These bases are poorly soluble in water and by their activity are close to the hydroxides of rare-earth metals. The strongest base is of actinium. All compounds of actinium are colorless, except for black actinium sulfide (Ac2S3).[26] Dioxides of tetravalent actinides crystallize in the cubic system, same as in calcium fluoride.

Thorium reacting with oxygen exclusively forms dioxide:

${\displaystyle ~\mathrm {Th+O_{2}\ {\xrightarrow {1000^{\circ }C}}\ ThO_{2}} }$

Thorium dioxide is a refractory material with the highest melting point among any known oxide (3390 °C).[24] Adding 0.8–1% ThO2 to tungsten stabilizes its structure, so the doped filaments have better mechanical stability to vibrations. To dissolve ThO2 in acids, it is heated to 500–600 °C; heating above 600 °C produces a very resistant to acids and other reagents form of ThO2. Small addition of fluoride ions catalyses dissolution of thorium dioxide in acids.

Two protactinium oxides were obtained: PaO2 (black) and Pa2O5(white); the former is isomorphic with ThO2 and the latter is easier to obtain. Both oxides are basic, and Pa(OH)5 is a weak, poorly soluble base.[26]

Decomposition of certain salts of uranium, for example UO2(NO3)·6H2O in air at 400 °C, yields orange or yellow UO3.[24] This oxide is amphoteric and forms several hydroxides, the most stable being UO2(OH)2. Reaction of uranium(VI) oxide with hydrogen results in uranium dioxide, which is similar in its properties with ThO2. This oxide is also basic and corresponds to the uranium hydroxide (U(OH)4).[26]

Plutonium, neptunium and americium form two basic oxides: An2O3 and AnO2. Neptunium trioxide is unstable; thus, only Np3O8 could be obtained so far. However, the oxides of plutonium and neptunium with the chemical formula AnO2 and An2O3 are well characterized.[26]

### Asin

*An – actinide
**Depending on the isotopes
Einsteinium triiodide glowing in the dark

Actinides easily react with halogens forming salts with the formulas MX3 and MX4 (X = halogen). So the first berkelium compound, BkCl3, was synthesized in 1962 with an amount of 3 nanograms. Like the halogens of rare earth elements, actinide chlorides, bromides, and iodides are water soluble, and fluorides are insoluble. Uranium easily yields a colorless hexafluoride, which sublimates at a temperature of 56.5 °C; because of its volatility, it is used in the separation of uranium isotopes with gas centrifuge or gaseous diffusion. Actinide hexafluorides have properties close to anhydrides. They are very sensitive to moisture and hydrolyze forming AnO2F2.[31] The pentachloride and black hexachloride of uranium were synthesized, but they are both unstable.[26]

## Talababa

1. The Manhattan Project. An Interactive History. US Department of Energy
2. Theodore Gray (2009). The Elements: A Visual Exploration of Every Known Atom in the Universe. New York: Black Dog & Leventhal Publishers. p. 240. ISBN 978-1-57912-814-2.
3. Actinide element, Encyclopædia Britannica on-line
4. Although "actinoid" (rather than "actinide") means "actinium-like" and therefore should exclude actinium, that element is usually included in the series.
5. Neil G. Connelly et al. (2005). "Elements". Nomenclature of Inorganic Chemistry. London: Royal Society of Chemistry. p. 52. ISBN 0-85404-438-8.
6. Greenwood, p. 1250
7. Fields, P.; Studier, M.; Diamond, H.; Mech, J.; Inghram, M.; Pyle, G.; Stevens, C.; Fried, S. et al. (1956). "Transplutonium Elements in Thermonuclear Test Debris". Physical Review 102 (1): 180. Bibcode 1956PhRv..102..180F. doi:10.1103/PhysRev.102.180.
8. I.L. Knunyants (1961). Short Chemical Encyclopedia. 1. Moscow: Soviet Encyclopedia.
9. Golub, pp. 218–219
10. Maling banggit (Hindi tamang <ref> tag; walang binigay na teksto para sa refs na may pangalang Yu. D. Tretyakov); $2 11. Greenwood, p. 1263 12. Maling banggit (Hindi tamang <ref> tag; walang binigay na teksto para sa refs na may pangalang emsley);$2
13. Peterson, Ivars (7 Disyembre 1991). "Uranium displays rare type of radioactivity". Science News.
14. Greenwood, p. 1265
15. Greenwood, p. 1264
16. Myasoedov, pp. 30–31
17. Maling banggit (Hindi tamang <ref> tag; walang binigay na teksto para sa refs na may pangalang Himiya aktiniya); $2 18. Maling banggit (Hindi tamang <ref> tag; walang binigay na teksto para sa refs na may pangalang Himiya neptuniya);$2
19. E.S. Palshin (1968). Analytical chemistry of protactinium. Moscow: Nauka.
20. Myasoedov, p. 88
21. According to other sources, cubic sesquioxide of curium is olive-green. See "Соединения curium site XuMuK.ru" (sa Russian). Sininop mula sa orihinal na pahina noong 18 Agosto 2010. Hinango noong 11 Hulyo 2010.
22. The atmosphere during the synthesis affects the lattice parameters, which might be due to non-stoichiometry as a result of oxidation or reduction of the trivalent californium. Main form is the cubic oxide of californium(III).
23. Greenwood, p. 1268
24. L.R. Morss, Norman M. Edelstein and Jean Fuger (2011). The Chemistry of the Actinide and Transactinide Elements (Set Vol.1–6). Springer. pp. 2139–. ISBN 978-94-007-0210-3.
25. Maling banggit (Hindi tamang <ref> tag; walang binigay na teksto para sa refs na may pangalang g222); \$2
26. Greenwood, p. 1270
27. Myasoedov, pp. 96–99
28. F. Weigel, J. Katz, G. Seaborg (1997). The Chemistry of the Actinide Elements. 2. Moscow: Mir. ISBN 5-03-001885-9.
29. Nave, S.; Haire, R.; Huray, Paul (1983). "Magnetic properties of actinide elements having the 5f6 and 5f7 electronic configurations". Physical Review B 28: 2317. Bibcode 1983PhRvB..28.2317N. doi:10.1103/PhysRevB.28.2317.
30. Greenwood, p.1269

## Bibliyograpiya

• Golub, A. M. (1971). Общая и неорганическая химия (General and Inorganic Chemistry). 2.