Carl Scheele, Swedish chemist, thiab Daniel Rutherford, ib tug Scottish botanist, nrhiav tau nitrogen nyias nyob rau hauv 1772. Reverend Cavendish thiab Lavoisier kuj ntawm nws tus kheej tau nitrogen nyob rau tib lub sij hawm. Nitrogen yog thawj zaug lees paub tias yog lub ntsiab lus los ntawm Lavoisier, uas tau muab nws lub npe "azo", lub ntsiab lus "inanimate". Chaptal hu ua lub ntsiab nitrogen nyob rau hauv 1790. Lub npe yog muab los ntawm Greek lo lus "nitre" (nitrate muaj nitrogen nyob rau hauv nitrate).
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Qhov chaw ntawm Nitrogen
Nitrogen yog 30th feem ntau cov khoom nyob hauv lub ntiaj teb. Xav txog tias nitrogen tso nyiaj rau 4/5 ntawm huab cua ntim, lossis ntau dua 78%, peb yuav luag tsis muaj qhov txwv tsis pub muaj nitrogen rau peb. Nitrogen kuj muaj nyob rau hauv daim ntawv ntawm nitrates nyob rau hauv ntau yam minerals, xws li Chilean saltpeter (sodium nitrate), saltpeter los yog nitre (potassium nitrate), thiab minerals uas muaj ammonium ntsev. Nitrogen muaj nyob rau hauv ntau complex organic molecules, nrog rau cov proteins thiab amino acids tam sim no nyob rau hauv tag nrho cov muaj sia nyob.
Lub cev muaj zog
Nitrogen N2 yog cov roj tsis muaj xim, tsis muaj ntxhiab, thiab tsw ntxhiab ntawm chav tsev kub, thiab feem ntau tsis muaj tshuaj lom. Gas ceev nyob rau hauv tus txheej txheem yog 1.25g / L. Nitrogen suav txog 78.12% ntawm tag nrho cov huab cua (feem feem) thiab yog lub ntsiab ntawm huab cua. Muaj li ntawm 400 trillion tons ntawm cov pa roj hauv cov cua.
Raws li tus qauv atmospheric siab, thaum txias mus rau -195.8 ℃, nws dhau los ua kua tsis muaj xim. Thaum txias rau -209.86 ℃, kua nitrogen ua cov khoom zoo li daus.
Nitrogen yog non-flammable thiab suav hais tias yog asphyxiating gas (piv txwv li, ua pa ntshiab nitrogen deprives tib neeg lub cev ntawm oxygen). Nitrogen muaj tsawg heev solubility hauv dej. Ntawm 283K, ib ntim dej tuaj yeem yaj txog 0.02 ntim N2.
Cov khoom siv tshuaj
Nitrogen muaj tshuaj lom neeg ruaj khov heev. Nws yog ib qho nyuaj rau kev hnov mob nrog lwm yam tshuaj nyob rau hauv chav tsev kub, tab sis nws tuaj yeem hloov pauv tshuaj lom neeg nrog qee yam tshuaj nyob rau hauv qhov kub thiab txias, thiab tuaj yeem siv los tsim cov tshuaj tshiab muaj txiaj ntsig rau tib neeg.
Cov mis molecular orbital ntawm nitrogen molecules yog KK σs2 σs * 2 σp2 σp * 2 πp2. Peb khub ntawm cov hluav taws xob ua rau kev sib txuas, uas yog, ob lub π bonds thiab ib qho σ daim ntawv cog lus tau tsim. Tsis muaj kev koom tes rau kev sib txuas lus, thiab kev sib koom ua ke thiab kev tiv thaiv kev sib koom tes yog kwv yees li offset, thiab lawv sib npaug rau ib leeg electron khub. Txij li thaum muaj triple daim ntawv cog lus N≡N nyob rau hauv N2 molecule, N2 molecule muaj kev ruaj ntseg zoo, thiab nws yuav siv sij hawm 941.69 kJ / mol ntawm lub zog kom decompose nws mus rau hauv atoms. N2 molecule yog qhov ruaj khov tshaj plaws ntawm cov kab mob hu ua diatomic molecules, thiab cov txheeb ze molecular loj ntawm nitrogen yog 28. Tsis tas li ntawd, nitrogen tsis yooj yim rau hlawv thiab tsis txhawb combustion.
Kev sim
Muab cov Mg hlawv rau hauv lub raj mis ntim roj uas muaj nitrogen, thiab Mg bar tseem yuav hlawv. Tshem tawm cov hmoov tshauv (me ntsis daj hmoov Mg3N2), ntxiv dej me me, thiab tsim cov roj (ammonia) uas hloov cov ntawv ntub dej liab litmus xiav. Reaction sib npaug: 3Mg + N2 = ignition = Mg3N2 (magnesium nitride); Mg3N2 + 6H2O = 3Mg (OH) 2 + 2NH3↑
Bonding yam ntxwv thiab valence bond qauv ntawm nitrogen
Vim hais tias ib qho tshuaj N2 yog qhov ruaj khov heev nyob rau hauv ib txwm muaj, tib neeg feem ntau yuam kev ntseeg tias nitrogen yog cov tshuaj tsis muaj zog. Qhov tseeb, ntawm qhov tsis sib xws, cov ntsiab lus nitrogen muaj cov tshuaj lom neeg siab. Lub electronegativity ntawm N (3.04) tsuas yog thib ob rau F thiab O, qhia tias nws tuaj yeem tsim cov ntawv cog lus muaj zog nrog lwm cov ntsiab lus. Tsis tas li ntawd, kev ruaj ntseg ntawm ib qho tshuaj N2 molecule tsuas yog qhia txog kev ua haujlwm ntawm N atom. Qhov teeb meem yog tias tib neeg tseem tsis tau pom qhov zoo tshaj plaws rau kev ua kom N2 molecules ntawm chav tsev kub thiab siab. Tab sis nyob rau hauv qhov xwm txheej, qee cov kab mob ntawm cov nroj tsuag nodules tuaj yeem hloov N2 hauv huab cua mus rau hauv nitrogen tebchaw nyob rau hauv qis-zog tej yam kev mob ntawm qhov kub thiab txias, thiab siv lawv ua chiv rau kev loj hlob qoob loo.
Yog li ntawd, kev kawm txog nitrogen fixation yeej ib txwm yog ib qho tseem ceeb kev tshawb fawb lub ntsiab lus. Yog li ntawd, nws yog ib qho tsim nyog rau peb kom nkag siab txog cov yam ntxwv ntawm kev sib koom tes thiab valence daim ntawv cog lus ntawm nitrogen kom meej.
Bond hom
Lub valence electron txheej txheej ntawm N atom yog 2s2p3, uas yog, muaj 3 ib leeg electrons thiab ib khub ntawm ib leeg electron khub. Raws li qhov no, thaum tsim cov tebchaw, cov hauv qab no peb hom nyiaj tau los tuaj yeem tsim tau:
1. Tsim cov ionic bonds 2. Ua covalent bonds 3. Tsim cov ntawv cog lus sib koom tes
1. Ua ionic bonds
N atoms muaj electronegativity siab (3.04). Thaum lawv tsim binary nitrides nrog hlau nrog qis electronegativity, xws li Li (electronegativity 0.98), Ca (electronegativity 1.00), thiab Mg (electronegativity 1.31), lawv tuaj yeem tau txais 3 electrons thiab daim ntawv N3- ions. N2+ 6 Li == 2 Li3N N2+ 3 Ca == Ca3N2 N2+ 3 Mg = ignite= Mg3N2 N3- ions muaj cov nqi tsis zoo dua thiab lub vojvoog loj dua (171pm). Lawv yuav muaj zog hydrolyzed thaum lawv ntsib cov dej molecules. Yog li ntawd, ionic compounds tsuas tuaj yeem nyob hauv lub xeev qhuav, thiab yuav tsis muaj hydrated ions ntawm N3-.
2. Tsim covalent bonds
Thaum N atoms tsim cov tebchaw nrog cov hlau tsis muaj hlau nrog ntau dua electronegativity, cov ntawv cog lus hauv qab no tau tsim:
⑴N atoms coj sp3 hybridization xeev, tsim peb covalent daim ntawv cog lus, khaws ib khub ntawm ib leeg electron khub, thiab cov qauv molecular yog trigonal pyramidal, xws li NH3, NF3, NCl3, thiab lwm yam. ib txwm tetrahedron, xws li NH4+ ions.
⑵N atoms coj sp2 hybridization xeev, tsim ob daim ntawv cog lus thiab ib daim ntawv cog lus, thiab khaws ib khub ntawm ib leeg electron khub, thiab cov qauv molecular yog angular, xws li Cl-N = O. (N atom tsim ib tug σ daim ntawv cog lus thiab π daim ntawv cog lus nrog Cl atom, thiab ib khub ntawm ib leeg electron khub ntawm N atom ua rau lub molecule daim duab peb sab. NO3- IB. Nyob rau hauv nitric acid molecule, N atom tsim peb σ bonds nrog peb O atoms feem, thiab ib khub ntawm electrons ntawm nws π orbital thiab ib leeg π electrons ntawm ob O atoms tsim ib tug peb-center plaub-electron delocalized π daim ntawv cog lus. Nyob rau hauv nitrate ion, plaub-center rau-electron delocalized loj π daim ntawv cog lus yog tsim ntawm peb O atoms thiab lub hauv paus N atom. Cov qauv no ua rau pom tseeb oxidation naj npawb ntawm N atom hauv nitric acid +5. Vim muaj qhov loj π bonds, nitrate ruaj khov txaus nyob rau hauv ib txwm muaj mob. ⑶N atom txais sp hybridization los tsim covalent triple daim ntawv cog lus thiab khaws cia ib khub ntawm ib leeg electron khub. Cov txheej txheem molecular yog linear, xws li cov qauv ntawm N atom hauv N2 molecule thiab CN-.
3. Tsim cov ntawv cog lus sib koom tes
Thaum nitrogen atoms tsim cov tshuaj yooj yim lossis cov khoom sib txuas, lawv feem ntau khaws cov khoom siv hluav taws xob ib leeg, yog li cov khoom siv yooj yim lossis cov khoom sib txuas tuaj yeem ua raws li cov khoom siv hluav taws xob sib koom ua ke rau cov hlau ions. Piv txwv li, [Cu(NH3)4]2+ or [Tu(NH2)5]7, etc.
Oxidation xeev-Gibbs dawb lub zog daim duab
Nws tseem tuaj yeem pom los ntawm oxidation xeev-Gibbs dawb lub zog daim duab ntawm nitrogen uas, tshwj tsis yog rau NH4 ions, N2 molecule nrog tus lej oxidation ntawm 0 yog ntawm qhov qis tshaj ntawm qhov nkhaus hauv daim duab, uas qhia tias N2 yog thermodynamically. ruaj khov txheeb ze rau nitrogen tebchaw nrog rau lwm cov oxidation tooj.
Cov txiaj ntsig ntawm ntau yam nitrogen tebchaw nrog oxidation tooj ntawm 0 thiab +5 yog tag nrho saum toj no cov kab txuas ob lub ntsiab lus HNO3 thiab N2 (kab dotted kab hauv daim duab), yog li cov tebchaw no yog thermodynamically tsis ruaj khov thiab muaj kev cuam tshuam tsis txaus ntseeg. Tsuas yog ib qho hauv daim duab nrog tus nqi qis dua N2 molecule yog NH4 + ion. [1] Los ntawm oxidation xeev-Gibbs dawb lub zog daim duab ntawm nitrogen thiab cov qauv ntawm N2 molecule, nws yuav pom tau hais tias elemental N2 yog inactive. Tsuas yog nyob rau hauv qhov kub thiab txias, siab siab thiab muaj cov catalyst muaj peev xwm nitrogen react nrog hydrogen los tsim ammonia: Nyob rau hauv cov xwm txheej paug, nitrogen tuaj yeem ua ke nrog oxygen los tsim nitric oxide: N2 + O2 = tso tawm = 2NO Nitric oxide sai ua ke nrog oxygen rau Daim ntawv nitrogen dioxide 2NO + O2 = 2NO2 Nitrogen dioxide dissolves hauv dej los tsim nitric acid, nitric oxide 3NO2 + H2O = 2HNO3 + NO Nyob rau hauv lub teb chaws uas tsim hydropower, cov tshuaj tiv thaiv no tau siv los tsim nitric acid. N2 reacts nrog hydrogen los tsim ammonia: N2 + 3H2 = = = (rov qab kos npe) 2NH3 N2 reacts nrog hlau nrog tsawg ionization muaj peev xwm thiab nws cov nitrides muaj siab lattice zog los tsim ionic nitrides. Piv txwv li: N2 tuaj yeem cuam tshuam ncaj qha nrog hlau lithium ntawm chav tsev kub: 6 Li + N2 === 2 Li3N N2 reacts nrog alkaline ntiaj teb hlau Mg, Ca, Sr, Ba ntawm incandescent kub: 3 Ca + N2 = = Ca3N2 N2 tau tsuas yog hnov qab nrog boron thiab txhuas ntawm qhov kub thiab txias: 2 B + N2 = = = 2 BN (macromolecule compound) N2 feem ntau reacts nrog silicon thiab lwm pab pawg ntawm qhov kub siab tshaj 1473K.
Nitrogen molecule pab peb khub ntawm electrons rau kev sib txuas, uas yog, ua ob π bonds thiab ib tug σ bond. Nws tsis ua rau kev sib raug zoo, thiab kev sib koom ua ke thiab kev tiv thaiv kev sib koom tes yog kwv yees li offset, thiab lawv sib npaug rau ib leeg electron khub. Vim tias muaj qhov sib npaug N≡N hauv N2 molecule, N2 molecule muaj kev ruaj ntseg zoo, thiab nws yuav siv 941.69kJ / mol ntawm lub zog kom decompose nws mus rau hauv atoms. N2 molecule yog qhov ruaj khov tshaj plaws ntawm cov kab mob hu ua diatomic molecules, thiab cov txheeb ze molecular loj ntawm nitrogen yog 28. Tsis tas li ntawd, nitrogen tsis yooj yim rau hlawv thiab tsis txhawb combustion.
Post lub sij hawm: Lub Xya hli ntuj-23-2024
