Helijum

Helijum
	odaje narandžasti sjaj u stanju plazme
Opšta svojstva
Ime, simbol	helijum, He
U periodnome sistemu
vodonik ← helijum → litijum	‍
Atomski broj (Z)	2
Grupa, perioda	grupa 18 (plemeniti gasovi), perioda 1
Blok	s-blok
Kategorija	plemeniti gas
Rel. at. masa (Ar)	4,002602(2)
El. konfiguracija	1s2
po ljuskama	2
Fizička svojstva
Boja	bezbojan
Agregatno stanje	gasovito
Tačka topljenja	0,95 K (−272,2 °‍C)
Tačka ključanja	4,22 K (−268,93 °C)
Gustina	0,1785 kg/m3
Molarna zapremina	21,0×10−3 m³/mol
Kritična temp.	5,19 K (−267,96 °C)
Toplota fuzije	5,23 kJ/mol
Toplota isparavanja	0,0845 kJ/mol
Sp. topl. kapacitet	5.193 J/(kg*K)
Atomska svojstva
Oksidaciona stanja	0
Energije jonizacije	1: 2.372,3 kJ/mol ; 2: 5.250,5 kJ/mol
Atomski radijus	bd (31) pm
Kovalentni radijus	32 pm
Valsov radijus	140 pm
	Spektralne linije
Ostalo
Kristalna struktura	heksagonalna
Brzina zvuka	970 m/s (298,15 K)
Topl. vodljivost	0,152 W/(m*K) W/(m·K)
CAS broj	7440-59-7
	reference • Vikipodaci

Helijum (latinično: He, lat. helium) je drugi hemijski element po lakoći, odmah posle vodonika.^[2] On je bezbojan, bezmirisan, bezukusan, netoksičan, inertan, monoatomski gas, prvi u grupi plemenitih gasova u periodnom sistemu. Njegova tačka ključanja je najniža od svih elemenata. Nakon vodonika, helijum je drugi najzastupljeniji element u vidljivom svemiru, sa učešćem od oko 24% ukupne elementarne mase, što je više od 12 puta masa svih težih elemenata zajedno. Njegova zastupljenost u Suncu i Jupiteru je na sličnom nivou. To je uzrokovano veoma visokom nuklearnom energijom vezivanja (po nukleonu) helijuma-4 u odnosu na sledeća tri elementa iza helijuma. Ova energija vezivanja helijuma-4 je isto tako razlog da je on produkat nuklearne fuzije i radioaktivnog raspada. Najveći deo helijuma u svemiru je helijum-4, od čega je većina formirana tokom Velikog praska. Velike količine novog helijuma se kreiraju putem nuklearne fuzije vodonika u zvezdama.

Helijum

Helijum je imenovan po grčkom Titanu Sunca, Heliju. On je prvi put bio detektovan kao nepoznata žuta spektralna linija karakteristična za sunčevu svetlost tokom solarne eklipse iz 1868. Za ovo otkriće su zaslužni Žorž Raje,^[3] kapetan C. T. Hejg,^[4] Norman R. Pogson,^[5] i poručnik Džon Heršel,^[6] i to je naknadno potvrdio fransuski astronom Pjer Jansen.^[7] Jansenu se često pridaju zasluge za detekciju ovog elementa zajedno sa Normanom Lokjerom. Jansen je snimio spektralnu liniju helijuma tokom pomračenja sunca iz 1868, dok je Lokjer to isto učinio u Britaniji. Lokjer je prvi predložio da je linija posledica novog elementa, koji je on imenovao. Formalno otkriće elementa su učinila 1895. godine dva švedska hemičara, Per Teodor Kliv i Nils Abraham Langlet, koji su našli da helijum proizilazi iz uranijumske rude klevejta. Godine 1903, velike rezerve helijuma su nađene na poljima prirodnog gasa u delovima Sjedinjenih Država, koje su daleko najveći snabdevač ovog gasa u današnje vreme.

Rasprostranjenost

Helijum je drugi po rasprostranjenosti hemijski element u vasioni, ali na Zemlji se javlja samo u tragovima (4 × 10^-7% u gornjim slojevima Zemlje). Helijum se na Zemlji uglavnom javlja u atmosferi (5,2 × 10^-4% u vazduhu). U litosferi helijum se takođe javlja, ali u veoma malim količinama. Praktično sav helijum koji je postojao na Zemlji nije mogao da gradi jedinjenja sa drugim elementima pa je zbog male mase napustio atmosferu Zemlje.

Izotopi i osobine

Javlja se u obliku 2 postojana izotopa — ³He i ⁴He kao i 4 nepostojana: ⁵He, ⁶He, ⁷He i ⁸He.

Helijum je plemeniti gas, najneaktivniji hemijski element, sa veoma velikom energijom jonizacije. Nema nikakav biološki značaj.^[8]

Upotreba

Helijum se u tečnom obliku koristi za hlađenje tamo gde su potrebne veoma niske temperature, zbog njegove niske tačke ključanja.
Tečni helijum koristi se za magnetne rezonance.
Kao najlakši siguran gas (nezapaljiv) koristio se za punjenje balona. Sada se sve ređe koristi zbog velikih troškova pri dobijanju, a umesto njega se najčešće koristi zagrejan vazduh.
Zbog male rastvorljivosti u krvi koristi se kao sastojak mešavine za ronjenje na velikim dubinama.

Balon ispunjen helijumom.

Dobijanje helijuma

Helijum se dobija raspadom radioaktivnih materijala koji emituju alfa čestice u središtu zemlje( alfa čestice imaju dva protona i dva neutrona i tokom prolaska kroz zemljinu koru pokupe dva elektrona).95% helijuma u zemlji se dobija prilikom raspada uranijuma i torijuma. Helijum se obično skuplja u nepropusnim džepovima zemljine kore gde se obično skuplja i zemni gas (metan) Ovog bogatog helijumom gasa najviše ima u SAD. Prilikom izlaska helijuma u atmosferu on prolazi kroz nju i odlazi u svemir.

Svetska produkcija helijuma iznosi oko 4500 tona u toku godine.

Način isporuke u industriji

Isporučuje se u gasovitom i tečnom stanju.
Gasoviti helijum se isporučuje komprimovan u čeličnim bocama, zapremine 6 m³; 7,5 m³ i 10 m³.

Postoji nekoliko vrsta čistoća: balon -gas 4.6; 5.0 i 6.0

Tečni helijum čistoće 5.0 se isporučuje u posudama, zapremina 50, 100, 250, 380 i 450 litara.

Biološki efekti

Brzina zvuka u helijumu je tri puta brža od brzine zvuka u vazduhu. Pošto je osnovna frekvencija gasom popunjenih šupljina proporcionalna brzini zvuka u gasu, udisanjem helijuma dolazi do odgovarajućeg povećanja visine tona rezonantne frekvencije vokalnog trakta.^[9]^[10] Ovo dovodi do stvaranja glasa visokog tona, nalik na pačji.

Prekomerno udisanje helijuma može biti opasno jer je helijum prosti asfiksijant koji zamenjuje kiseonik potreban za normalno disanje.^[9]^[11] Konstantno udisanje čistog helijuma dovodi do smrti za nekoliko minuta zbog asfiksacije (gušenja). Udisanje čistog helijuma iz cilindara pod pritiskom je izuzetno opasno, jer visok protok može dovesti do barotraume i fatalnog cepanja plućnog tkiva.^[11]^[12] Smrt uzrokovana helijumom nije česta, ali su u Sjedinjenim Državama između 2000. i 2004. zabeležena dva smrtna slučaja.^[12]

Efekat helijuma na ljudski glas

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Reference

^ Meija, J.; et al. (2016). „Atomic weights of the elements 2013 (IUPAC Technical Report)”. Pure and Applied Chemistry. 88 (3): 265—291. doi:10.1515/pac-2015-0305.
^ Housecroft, C. E.; Sharpe, A. G. (2008). Inorganic Chemistry (3. izd.). Prentice Hall. ISBN 978-0-13-175553-6.
^ Rayet, G. (1868) "Analyse spectral des protubérances observées, pendant l'éclipse totale de Soleil visible le 18 août 1868, à la presqu'île de Malacca" (Spectral analysis of the protuberances observed during the total solar eclipse, seen on 18 August 1868, from the Malacca peninsula), Comptes rendus ... , 67 : 757–759. From p. 758: " ... je vis immédiatement une série de neuf lignes brillantes qui ... me semblent devoir être assimilées aux lignes principales du spectre solaire, B, D, E, b, une ligne inconnue, F, et deux lignes du groupe G." ( ... I saw immediately a series of nine bright lines that ... seemed to me should be classed as the principal lines of the solar spectrum, B, D, E, b, an unknown line, F, and two lines of the group G.)
^ Captain C. T. Haig (1868) "Account of spectroscopic observations of the eclipse of the sun, August 18th, 1868," Proceedings of the Royal Society of London, 17 : 74–80. From p. 74: "I may state at once that I observed the spectra of two red flames close to each other, and in their spectra two broad bright bands quite sharply defined, one rose-madder and the other light golden."
^ Pogson filed his observations of the 1868 eclipse with the local Indian government, but his report wasn't published. (Biman B. Nath, The Story of Helium and the Birth of Astrophysics (New York, New York: Springer, 2013), p. 8.) Nevertheless, Lockyer quoted from his report. From p. 320 of Lockyer, J. Norman (1896) "The story of helium. Prologue," Nature, 53 : 319–322 : "Pogson, in referring to the eclipse of 1868, said that the yellow line was "at D, or near D." "
^ Lieutenant John Herschel (1868) "Account of the solar eclipse of 1868, as seen at Jamkandi in the Bombay Presidency," Proceedings of the Royal Society of London, 17 : 104–120. From p. 113: As the moment of the total solar eclipse approached, " … I recorded an increasing brilliancy in the spectrum in the neighborhood of D, so great in fact as to prevent any measurement of that line till an opportune cloud moderated the light. I am not prepared to offer any explanation of this." From p. 117: "I also consider that there can be no question that the ORANGE LINE was identical with D, so far as the capacity of the instrument to establish any such identity is concerned."
^
In his initial report to the French Academy of Sciences about the 1868 eclipse, Janssen made no mention of a yellow line in the solar spectrum. See:
- Janssen (1868) "Indication de quelques-uns des résultats obtenus à Cocanada, pendant l'éclipse du mois d'août dernier, et à la suite de cette éclipse" (Information on some of the results obtained at Cocanada, during the eclipse of the month of last August, and following that eclipse), Comptes rendus ... , 67 : 838–839.
- Wheeler M. Sears, (2015). Helium: The Disappearing Element. Heidelberg, Germany: Springer. ,
- Françoise Launay with Storm Dunlop, trans., The Astronomer Jules Janssen: A Globetrotter of Celestial Physics (Heidelberg, Germany: Springer, 2012), p. 45.
However, subsequently, in an unpublished letter of 19 December 1868 to Charles Sainte-Claire Deville, Janssen asked Deville to inform the French Academy of Sciences that : "Several observers have claimed the bright D line as forming part of the spectrum of the prominences on 18 August. The bright yellow line did indeed lie very close to D, but the light was more refrangible [i.e., of shorter wavelength] than those of the D lines. My subsequent studies of the Sun have shown the accuracy of what I state here." (See: (Launay, 2012), p. 45.)
^ Parkes, G.D. & Phil, D. (1973). Melorova moderna neorganska hemija. Beograd: Naučna knjiga.
^ ^a ^b Emsley 2001
^ Ackerman MJ, Maitland G (1975). „Calculation of the relative speed of sound in a gas mixture”. Undersea Biomed Res. 2 (4): 305—10. PMID 1226588. Arhivirano iz originala 27. 01. 2011. g. Pristupljeno 9. 8. 2008. (jezik: engleski)
^ ^a ^b Grassberger, Martin; Krauskopf, Astrid (2007). „Suicidal asphyxiation with helium: Report of three cases Suizid mit Helium Gas: Bericht über drei Fälle”. Wiener Klinische Wochenschrift (na jeziku: German & English). 119 (9–10): 323—325. PMID 17571238. doi:10.1007/s00508-007-0785-4. (jezik: engleski)
^ ^a ^b Engber, Daniel (13. 6. 2006). „Stay Out of That Balloon!”. Slate.com. Pristupljeno 14. 7. 2008. (jezik: engleski)

Literatura

Emsley, John (2001). Nature's Building Blocks. Oxford: Oxford University Press. str. 175—179. ISBN 978-0-19-850341-5. (jezik: engleski)
Mines, Bureau of (1967). Minerals yearbook mineral fuels Year 1965. II. U. S. Government Printing Office.
The Impact of Selling the Federal Helium Reserve. Committee on the Impact of Selling the Federal Helium Reserve, Commission on Physical Sciences, Mathematics, and Applications, Commission on Engineering and Technical Systems, National Research Council. The National Academies Press. 2000. ISBN 978-0-309-07038-6. Pristupljeno 2. 4. 2010.
Emsley, John (1998). The Elements (3rd izd.). New York: Oxford University Press. ISBN 978-0-19-855818-7.
Vercheval, J. (2003). „The thermosphere: a part of the heterosphere”. Belgian Institute for Space Aeronomy. Arhivirano iz originala 1. 1. 2005. g. Pristupljeno 12. 7. 2008.

Spoljašnje veze

(jezik: srpski) Proizvođač u Beogradu
(jezik: engleski) Helijum na vebelementima
(jezik: engleski) To je element - Helijum
(jezik: engleski) Slike helijuma

Generalno

U.S. Government's Bureau of Land Management: Sources, Refinement, and Shortage.
U.S. Geological Survey publications on helium beginning 1996: Helium
Where is all the helium? Aga website
It's Elemental – Helium
Chemistry in its element podcast (MP3) from the Royal Society of Chemistry's Chemistry World: Helium
International Chemical Safety Cards – Helium

Detaljnije

Helium at The Periodic Table of Videos (University of Nottingham)
Helium at the Helsinki University of Technology; includes pressure-temperature phase diagrams for helium-3 and helium-4
Lancaster University, Ultra Low Temperature Physics – includes a summary of some low temperature techniques

Razno

Physics in Speech with audio samples that demonstrate the unchanged voice pitch
Article about helium and other noble gases

Nestašica helijuma

America’s Helium Supply: Options for Producing More Helium from Federal Land: Oversight Hearing before the Subcommittee on Energy and Mineral Resources of the Committee on Natural Resources, U.S. House Of Representatives, One Hundred Thirteenth Congress, First Session, Thursday, July 11, 2013
Helium Program: Urgent Issues Facing BLM's Storage and Sale of Helium Reserves: Testimony before the Committee on Natural Resources, House of Representatives Government Accountability Office
Kramer, David (22. 5. 2012). „Senate bill would preserve US helium reserve: Measure would give scientists first dibs on helium should a shortage develop. Physics Today web site”. Arhivirano iz originala 27. 10. 2012. g.
Richardson, Robert C.; Chan, Moses (2009). „Helium, when will it run out?” (PDF). Arhivirano iz originala (PDF) 14. 6. 2015. g.

[CIAAW2016-1] Meija, J.; et al. (2016). „Atomic weights of the elements 2013 (IUPAC Technical Report)”. Pure and Applied Chemistry. 88 (3): 265—291. doi:10.1515/pac-2015-0305.

[Housecroft3rd-2] Housecroft, C. E.; Sharpe, A. G. (2008). Inorganic Chemistry (3. izd.). Prentice Hall. ISBN 978-0-13-175553-6.

[3] Rayet, G. (1868) "Analyse spectral des protubérances observées, pendant l'éclipse totale de Soleil visible le 18 août 1868, à la presqu'île de Malacca" (Spectral analysis of the protuberances observed during the total solar eclipse, seen on 18 August 1868, from the Malacca peninsula), Comptes rendus ... , 67 : 757–759. From p. 758: " ... je vis immédiatement une série de neuf lignes brillantes qui ... me semblent devoir être assimilées aux lignes principales du spectre solaire, B, D, E, b, une ligne inconnue, F, et deux lignes du groupe G." ( ... I saw immediately a series of nine bright lines that ... seemed to me should be classed as the principal lines of the solar spectrum, B, D, E, b, an unknown line, F, and two lines of the group G.)

[4] Captain C. T. Haig (1868) "Account of spectroscopic observations of the eclipse of the sun, August 18th, 1868," Proceedings of the Royal Society of London, 17 : 74–80. From p. 74: "I may state at once that I observed the spectra of two red flames close to each other, and in their spectra two broad bright bands quite sharply defined, one rose-madder and the other light golden."

[5] Pogson filed his observations of the 1868 eclipse with the local Indian government, but his report wasn't published. (Biman B. Nath, The Story of Helium and the Birth of Astrophysics (New York, New York: Springer, 2013), p. 8.) Nevertheless, Lockyer quoted from his report. From p. 320 of Lockyer, J. Norman (1896) "The story of helium. Prologue," Nature, 53 : 319–322 : "Pogson, in referring to the eclipse of 1868, said that the yellow line was "at D, or near D." "

[6] Lieutenant John Herschel (1868) "Account of the solar eclipse of 1868, as seen at Jamkandi in the Bombay Presidency," Proceedings of the Royal Society of London, 17 : 104–120. From p. 113: As the moment of the total solar eclipse approached, " … I recorded an increasing brilliancy in the spectrum in the neighborhood of D, so great in fact as to prevent any measurement of that line till an opportune cloud moderated the light. I am not prepared to offer any explanation of this." From p. 117: "I also consider that there can be no question that the ORANGE LINE was identical with D, so far as the capacity of the instrument to establish any such identity is concerned."

[7] In his initial report to the French Academy of Sciences about the 1868 eclipse, Janssen made no mention of a yellow line in the solar spectrum. See:
Janssen (1868) "Indication de quelques-uns des résultats obtenus à Cocanada, pendant l'éclipse du mois d'août dernier, et à la suite de cette éclipse" (Information on some of the results obtained at Cocanada, during the eclipse of the month of last August, and following that eclipse), Comptes rendus ... , 67 : 838–839.

Wheeler M. Sears, (2015). Helium: The Disappearing Element. Heidelberg, Germany: Springer. ,

Françoise Launay with Storm Dunlop, trans., The Astronomer Jules Janssen: A Globetrotter of Celestial Physics (Heidelberg, Germany: Springer, 2012), p. 45.
However, subsequently, in an unpublished letter of 19 December 1868 to Charles Sainte-Claire Deville, Janssen asked Deville to inform the French Academy of Sciences that : "Several observers have claimed the bright D line as forming part of the spectrum of the prominences on 18 August. The bright yellow line did indeed lie very close to D, but the light was more refrangible [i.e., of shorter wavelength] than those of the D lines. My subsequent studies of the Sun have shown the accuracy of what I state here." (See: (Launay, 2012), p. 45.)

[8] Janssen (1868) "Indication de quelques-uns des résultats obtenus à Cocanada, pendant l'éclipse du mois d'août dernier, et à la suite de cette éclipse" (Information on some of the results obtained at Cocanada, during the eclipse of the month of last August, and following that eclipse), Comptes rendus ... , 67 : 838–839.

[9] Wheeler M. Sears, (2015). Helium: The Disappearing Element. Heidelberg, Germany: Springer. ,

[10] Françoise Launay with Storm Dunlop, trans., The Astronomer Jules Janssen: A Globetrotter of Celestial Physics (Heidelberg, Germany: Springer, 2012), p. 45.

[ParkesNeorganskaHemija-8] Parkes, G.D. & Phil, D. (1973). Melorova moderna neorganska hemija. Beograd: Naučna knjiga.

[nbb-9] Emsley 2001

[10] Ackerman MJ, Maitland G (1975). „Calculation of the relative speed of sound in a gas mixture”. Undersea Biomed Res. 2 (4): 305—10. PMID 1226588. Arhivirano iz originala 27. 01. 2011. g. Pristupljeno 9. 8. 2008. (jezik: engleski)

[Grass-11] Grassberger, Martin; Krauskopf, Astrid (2007). „Suicidal asphyxiation with helium: Report of three cases Suizid mit Helium Gas: Bericht über drei Fälle”. Wiener Klinische Wochenschrift (na jeziku: German & English). 119 (9–10): 323—325. PMID 17571238. doi:10.1007/s00508-007-0785-4. (jezik: engleski)

[slate-12] Engber, Daniel (13. 6. 2006). „Stay Out of That Balloon!”. Slate.com. Pristupljeno 14. 7. 2008. (jezik: engleski)

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