Fluoride yog dab tsi? Cov khoom ntawm fluorine

Fluorine yog tshuaj keeb (cim F, atomic number 9), non-hlau, uas belongs rau cov pab pawg neeg halogens. Qhov no yog qhov tseem ceeb tshaj plaws thiab cov khoom siv hauv tshuab hluav taws xob. Thaum txwm kub thiab siab ntawm cov fluorine molecule yog ib tug lom roj daj daj nrog mis F _2. Zoo li lwm cov neeg halogens, molecular fluoride yog qhov txaus ntshai thiab, thaum sib chwv nrog rau ntawm daim tawv nqaij, ua kom kub hnyav heev.

Siv

Fluorine thiab nws cov tebchaw yog siv dav, suav nrog rau kev lag luam, agrochemicals, fuels thiab lubricants thiab textiles. Hydrofluoric acid yog siv los kos iav, thiab cov ntshav ntawm fluorine - rau qhov siv thiab ua semiconductor thiab lwm yam ntaub ntawv. Tsi cov concentration ntawm F ions nyob rau hauv cov tshuaj txhuam hniav thiab dej haus tuaj yeem pab tiv thaiv kev kho hniav kabmob, thaum qis ntau dua yog ib feem ntawm cov tshuaj tua kabmob (insecticides). Ntau yam tshuaj loog ntau yog cov dej hiav txwv ntawm hydrofluorocarbons. ¹⁸ F isotope yog ib tug positron qhov chaw rau kev kho mob ntsuam los ntawm positron emission tomography, thiab uranium hexafluoride yog siv rau lub sib cais ntawm isotopes ntawm uranium thiab tsim enriched uranium rau nuclear fais fab nroj tsuag.

Keeb kwm ntawm kev nrhiav pom

Cov zaub mov uas muaj cov tshuaj fluorine tau paub ntau xyoo ua ntej tso tawm ntawm cov tshuaj no. Piv txwv li, lub mineral fluorspar (los yog fluorite), muaj raws ntawm calcium fluoride, piav nyob rau hauv 1530 los ntawm Agricola G. Gheorghiu. Nws pom hais tias nws tuaj yeem siv tau raws li dej dawb - ib yam khoom uas yuav pab txo lub pob zeb ntawm cov hlau los yog hlau thiab pab tu hlau. Yog li no fluorine lub npe nws lub npe Latin tau txais los ntawm lo lus fluere ("leak").

Thaum 1670, iav iav Heinrich Schwanhard tau pom tias cov iav yog etched nyob hauv tus kab mob calcium fluoride (fluorspar) kho cov kua qaub. Karl Scheele thiab ntau cov neeg tshawb nrhiav, Humphry Davy, Joseph-Louis Gay-Lussac, Antoine Lavoisier, Louis Tenar, tau sim nrog hydrofluoric acid (HF), uas tau yooj yim tau los ntawm kev kho CaF nrog concentrated sulfuric acid.

Thaum kawg, nws paub tseeb tias HF muaj keeb tsis paub dua. Cov tshuaj no, txawm li cas los xij, vim nws qhov teeb meem ntau dhau xyoo rau ntau xyoo yuav tsis raug txheeb xyuas. Nws tsis yog tsuas yog nyuaj rau cais los ntawm sib txuas, tab sis nws tam sim ntawd reacts nrog lwm yam. Qhov kev rho tawm ntawm elemental fluorine los ntawm hydrofluoric acid yog qhov tsis tshua muaj neeg txaus ntshai, thiab ntxov ua rau dig muag thiab tua ntau tus kws tshawb fawb. Cov neeg no tau hu ua "martyrs ntawm fluoride".

Qhib thiab tsim khoom

Thaum kawg, hauv xyoo 1886, Fabkis chemist Henri Moissan tau muab cais tawm hauv qhov tawm ntawm cov tshuaj fluorine los ntawm electrolysis ntawm qhov sib tov ntawm cov hmoov phom plawv thiab hydrofluoric acid. Vim nws tau txais qhov Nobel Prize hauv 1906 hauv lub tshav pob ntawm chemistry. Nws txoj kev coj mus los ntawm electrolytic tseem niaj hnub siv rau kev tsim cov tshuaj ntawm cov tshuaj no.

Thawj qhov loj ntawm cov tshuaj fluoride tau pib thaum Tsov Rog Thoob Ntiaj Teb thib ob. Nws tau tsim nyog rau ib qho ntawm cov theem ntawm cov creation ntawm lub foob pob atomic hauv lub moj khaum ntawm qhov project Manhattan. Fluorine yog siv rau cov uranium hexafluoride (uf ₆₎ uas, nyob rau hauv lem, siv rau kev nkauj nraug los ntawm txhua lwm yam ob isotopes ²³⁵ U thiab ²³⁸ U. Niaj hnub no gaseous uf ₆ yuav tsum tau enriched uranium rau nuclear fais fab.

Qhov tseem ceeb tshaj plaws ntawm cov tshuaj fluoride

Nyob rau hauv lub rooj thawm xyoo, lub caij no yog nyob rau hauv nruab nrab ntawm pawg 17 (pawg qub 7A), uas yog hu ua halogen. Lwm cov halogens muaj chlorine, bromine, iodine thiab astatine. Ntxiv rau, F yog nyob rau lub sijhawm ob ntawm oxygen thiab neon.

Ntshiab Fluoro - ib tug corrosive roj (tshuaj mis F ₂₎ nrog ib tug yam ntxwv pungent tsw uas yog kuaj ntawm ib tug concentration ntawm 20 nl ib liter. Raws li feem ntau reactive thiab electronegative ntawm tag nrho cov ntsiab, nws yooj yim cov ntaub ntawv tebchaw nrog lawv feem ntau. Fluorine yog ib yam nkaus thiab tsis pom muaj nyob rau hauv daim ntawv elemental thiab muaj xws li ib qho affinity nrog rau ntau cov ntaub ntawv, xws li silicon, tias nws tsis tuaj yeem noj lossis cia rau hauv lub khob ntim. Nyob rau hauv cov huab cua lom zem, nws reacts nrog dej, sib sau ua ib qho dej phom sij zoo sib xws.

Fluorine, reacting nrog hydrogen, cia li tawg qis thiab hauv qhov tsaus ntuj. Nws reacts violently nrog dej, tsim hydrofluoric acid thiab gaseous oxygen. Ntau yam ntaub ntawv, nrog rau cov hlau nplaum thiab cov iav, hlawv hauv cov kwj deg roj fluorine nrog lub nplaim taws. Tsis tas li ntawd, cov tshuaj no siv cov tshuaj sib xyaw nrog cov roj hmab cov roj hmab, cov xenon thiab radon. Txawm li cas los xij, nws tsis hnov mob ncaj qha nrog nitrogen thiab oxygen.

Txawm tias muaj cov dej tshuaj fluoride heev, txoj hauv kev ua kom zoo thiab kev thauj mus los muaj hnub no. Lub caij yuav muab khaws cia rau hauv cov thawv uas ua los ntawm cov hlau los yog lub plhaub (cov nplaum uas muaj roj nplua nuj nickel), vim cov tshuaj fluorides raug tsim rau saum npoo ntawm cov ntaub ntawv, uas tiv thaiv cov tshuaj tiv thaiv ntxiv.

Cov tshuaj fluorides yog cov khoom uas muaj cov tshuaj fluorine tam sim no ua ib qho ion (F) uas tsis zoo los ua ke nrog qee cov ntsiab lus zoo. Cov tshuaj fluorine nrog cov hlau yog ib qho ntawm cov ntsev ntau yam ruaj khov. Thaum yaj hauv dej, lawv raug faib ua ions. Lwm yam ntaub ntawv ntawm cov fluorine yog ceg, e.g., [FeF _4] ^-, thiab H ₂ F ^+.

Isotopes

Muaj yog ib tug plurality ntawm isotopes ntawm halogen, los ntawm ¹⁴ F thiab xaus nrog ³¹ F. Tab sis fluorine isotope muaj pes tsawg leeg muaj xwb ib tug ntawm lawv, ¹⁹ F, uas muaj 10 neutrons, li ntawd, sai li sai tau raws li nws yog ruaj khov. Cov neeg isotope ¹⁸ F - ib tug tseem ceeb qhov chaw ntawm positrons.

Lom zem feem

Fluoride nyob rau hauv lub cev yog pom nyob rau hauv cov pob txha thiab cov hniav hauv daim ntawv ntawm ions. Fluoridation ntawm cov dej haus ntawm cov concentration ntawm tsawg dua ib feem ntawm ib lab dramatically txo cov xwm txheej ntawm caries - raws li National Research Council ntawm National Academy of Sciences. Ntawm qhov tod tes, qhov ntau dhau ntawm cov tshuaj fluoride tuaj yeem ua rau cov tshuaj fluorosis, uas ua rau nws tus kheej nyob rau hauv cov kaus hniav ntawm cov hniav. Cov nyhuv no feem ntau pom nyob rau cov cheeb tsam uas cov ntsiab lus ntawm cov tshuaj hauv cov dej haus no ntau dua li ntawm 10 ppm.

Elemental fluoride thiab fluoride ntsev yog lom thiab yuav tsum tau kho nrog kev saib xyuas zoo. Hu rau daim tawv nqaij los yog qhov muag yuav tsum ua tib zoo pov tseg. Cov tshuaj tiv thaiv nrog cov tawv nqaij ua rau hydrofluoric acid, uas ceev nrig mus los ntawm cov ntaub so ntswg thiab reacts nrog calcium uas nyob hauv cov pob txha, ua rau lawv mus tas li.

Fluoride nyob rau hauv ib puag ncig

Xyoo tagnrho lub ntiaj teb muaj cov tshuaj fluorite yog li ntawm 4 lab tons, thiab tag nrho cov peev txheej ntawm cov kev tshawb nrhiav cov khoom siv yog nyob rau hauv 120 lab tons Cov cheeb tsam tseem ceeb rau cov pob zeb no yog Mexico, Tuam Tshoj thiab Western Europe.

Nyob hauv cov xwm txheej, cov tshuaj fluoride nyob hauv lub ntiaj teb ua kaub puab, qhov twg nws tuaj yeem pom nyob rau hauv cov pob zeb, cov nplaum thiab av nplaum. Cov tshuaj fluorides poob rau hauv cov huab cua nrog cua yaig ntawm xau. Fluorine yog 13th feem ntau cov tshuaj chemical hauv lub ntiaj teb ua kiav txhab - nws cov ntsiab lus yog 950 ppm. Hauv av, nws qhov nruab nrab concentration yog li 330 ppm. Hydrogen fluoride tuaj yeem tso tawm rau hauv cov cua vim yog kev sib ntau sib txuas hauv kev lag luam. Cov tshuaj fluorides uas nyob hauv cov huab cua nws thiaj li poob mus rau hauv av los yog hauv dej. Thaum cov tshuaj fluorine ua ib daim ntawv cog lus nrog cov khoom me me, nws tuaj yeem nyob hauv cov huab cua ntev ntev.

Nyob rau hauv qhov chaw, 0,6 billionths ntawm no keeb tshuaj yog tam sim no ua ntsev pos thiab organic chlorine compounds. Hauv nroog loj, qhov concentration nce mus txog 50 feem ntawm ib npib nyiaj.

Kev Sib Txuas

Fluorine yog ib hom tshuaj chemical uas ua tau ntau yam ntawm cov organic thiab cov cheebtsam. Chemists muaj peev xwm hloov tau lawv nrog cov atoms hydrogen, uas tsim tau ntau yam tshuaj tshiab. Highly reactive halogen forms sib txuas nrog noble gases. Hauv xyoo 1962, Neil Bartlett tau coj los ua xenon hexafluoroplatinate (XePtF6). Fluorides ntawm krypton thiab radon kuj tau. Lwm cov paj xyoob yog argon fluoride, uas ruaj khov thaum sov tsis tshua muaj pes tsawg.

Muaj Cov Ntawv Thov

Hauv lub chaw atomic and molecular state, fluorine yog siv rau cov ntshav siab nyob rau hauv cov khoom ntawm semiconductors, cov lus qhia ncaj thiab cov tshuab microelectromechanical. Hydrofluoric acid yog siv rau etching iav hauv cov roj thiab lwm cov khoom.

Ua ke nrog qee lub tshooj ntawm nws, cov tshuaj fluoride yog ib qho tseem ceeb ntawm kev tsim tshuaj, qoob loo, roj thiab lubricants thiab textiles. Cov tshuaj no yog tsim nyog rau kev tsim cov halogenated alkanes (halons), uas, tig mus, siv dav hauv cua txias thiab txias tshuab. Tom qab, kev siv chlorofluorocarbons zoo li no raug txwv, raws li lawv ua rau kev puas tsuaj ntawm tus txheej txheem ozone hauv qib siab.

Sulfur hexafluoride yog ib qho tsis tshua muaj inert, tsis muaj roj toxic ntsig txog cov khoom uas ua rau lub tsev txawb hluav taws. Tsis muaj fluorine tsis yooj yim sua los tsim yas nrog ib tug tsawg coefficient ntawm tsis sib haum xeeb, xws li Teflon. Ntau yam tshuaj loog (piv txwv, sevoflurane, desflurane thiab isoflurane) yog cov dej caw ntawm hydrofluorocarbons. Sodium hexafluoroaluminuminate (cryolite) yog siv nyob rau hauv lub electrolysis ntawm txhuas.

Cov tshuaj Fluorine, nrog rau NaF, yog siv tshuaj txhuam hniav los tiv thaiv kabmob. Cov tshuaj no yog ntxiv rau cov dej haus hauv lub nroog rau cov dej haus tshuaj, tab sis vim muaj kev noj qab haus huv, qhov kev xyaum no yog teeb meem. Thaum muaj ntau dua, NaF yog siv los ua cov tshuaj tua kab mob, tshwj xeeb tshaj yog rau kev tswj cov kab laib.

Nyob rau hauv lub dhau los lawm, fluorides siv los txo hlau melting kub thiab ores, thiab kom lawv tawm los. Fluorine yog ib qho tseem ceeb ntawm kev tsim cov uranium hexafluoride, uas yog siv los cais cov isotopes. ¹⁸ F, lub tej isotope nrog ib tug ib nrab neej ntawm 110 feeb, emits positrons thiab yog feem ntau siv nyob rau hauv kev kho mob positron emission tomography.

Lub cev ntawm cov tshuaj fluorine

Cov yam ntxwv ntawm cov tshuaj muaj hauv paus muaj xws li hauv qab no:

• Lub npe atomic yog 18,9984032 g / mol.
• Cov hluav taws xob configuration ntawm 1s 2s ^{2 2 5} _2p.
• Degree ntawm oxidation -1.
• Qhov ntom yog 1.7 g / l.
• Melting point 53.53 K.
• Lub hau kub yog 85.03 K.
• Lub tshav kub yog 31.34 J / (K · mol).