Nyob rau hauv phosphorus chemistry system, phosphorous acid (H₃PO₃), phosphoric acid (H₃PO₄), hypophosphorous acid (H₃PO₂), thiab lwm yam phosphoric acids muaj nyob rau hauv phosphorus oxoacid tsev neeg, tab sis lawv txawv heev nyob rau hauv cov xim liab / oxoacid qauv, acidity thiab molecular qauv. Kev qhia meej txog qhov sib txawv no yog qhov tseem ceeb rau kev xaiv cov xwm txheej tsim nyog thiab txhim kho cov txheej txheem tsim.
Los ntawm cov qauv molecular foundations, lub hauv paus phosphorus atom ntawm phosphorous acid yog nyob rau hauv +3 oxidation xeev. Cov molecule muaj ib qho hydrogen atom ncaj qha sib txuas rau phosphorus (P-H daim ntawv cog lus), ob pawg hydroxyl (–OH), thiab ib qho P=O ob daim ntawv cog lus, nthuav tawm ib qho sp³ hybridized tetrahedral configuration. Phosphoric acid (H₃PO₄) muaj phosphorus nyob rau hauv +5 oxidation xeev, thiab cov molecule muaj peb hydroxyl pawg thiab ib tug P=O ob daim ntawv cog lus, tab sis tsis muaj P-H daim ntawv cog lus, faib nws raws li ib tug tricarboxylic acid. Hypophosphorous acid (H₃PO₂) kuj muaj phosphorus nyob rau hauv +1 oxidation lub xeev, tab sis tsuas muaj ib pawg hydroxyl thiab ob P-H bonds, faib nws raws li ib tug monocarboxylic acid. Qhov sib txawv ntawm cov qauv no ncaj qha ua rau muaj kev sib txawv hauv acidity thiab reactivity: phosphorous acid, tsuas yog ob lub hydroxyl hydrogens muaj peev xwm ntawm ionization, yog ib qho binary muaj zog acid; phosphoric acid, nrog peb protons, yog ib tug muaj zog acid thiab ib tug tribasic acid; hypophosphite, tsuas yog ib qho hydroxyl hydrogen, yog cov kua qaub qis tshaj plaws.
Qhov sib txawv ntawm acidity thiab hauv paus ntsiab lus ntxiv cuam tshuam rau lawv cov kev siv. Phosphorous acid tsis muaj zog acidity thiab binary xwm ua rau nws yooj yim dua nyob rau hauv kev kho mob ntawm hlau nto los yog synthesis tshwm sim yuav tsum tau tswj proton concentrations; phosphoric acid, vim nws cov acidity muaj zog thiab ntau yam -cov khoom sib xyaw, feem ntau yog siv hauv cov chiv, zaub mov acidulants, thiab lwm yam kev siv uas yuav tsum tau muaj zog acid ib puag ncig; hypophosphite, nrog rau nws cov acidity tsis tshua muaj zog tab sis muaj zog txo cov khoom, feem ntau yog siv hauv electroless plating, tshuaj intermediate synthesis, thiab lwm yam kev siv uas yuav tsum tau txo hwj chim.
Redox zog yog qhov tseem ceeb tshaj plaws ua haujlwm sib txawv ntawm peb. Phosphorous acid, vim muaj P-H bonds, muaj phosphorus nyob rau hauv qis oxidation xeev (+3), nthuav tawm ob qho tib si txo cov khoom thiab qee qhov kev sib koom tes. Nws tuaj yeem txo qhov siab -valence hlau ions los yog ua haujlwm ua ntej rau kev sib txuas ntawm phosphite esters. Phosphoric acid, nrog phosphorus nyob rau hauv nws lub siab ruaj khov oxidation xeev (+5), feem ntau nthuav tawm acidity thiab kev sib koom tes muaj peev xwm, uas yuav luag tsis muaj kev txo qis zog. Hypophosphoric acid, vim nws ob P-H daim ntawv cog lus, muaj zog txo cov zog dua li phosphorous acid, yooj yim dua txo cov hlau ions mus rau xoom valence, ua rau hlau deposition yam tsis tau siv tam sim no hauv electroless plating.
Lawv thermal stability thiab kev hloov pauv tus cwj pwm kuj txawv. Phosphorous acid dehydrates rau phosphoric acid thaum cua sov txog li 180 degree; phosphoric acid yog qhov ruaj khov ntawm qhov kub thiab txias, yuav tsum muaj zog dua kom decompose rau hauv metaphosphoric acid, thiab lwm yam; hypophosphoric acid yooj yim decomposes rau hauv phosphorus monoxide thiab dej thaum cua sov, nthuav tawm ntau tshaj tawm txo cov khoom thiab tsis ruaj khov.
Hauv cov ntsiab lus, phosphorous acid, nrog nws cov yam ntxwv dicarboxylic acid, txo qis zog, thiab cov cim reactivity tau muab los ntawm P-H bonds, distinguishes nws tus kheej los ntawm lub zog acidity thiab siab oxidation xeev stability ntawm phosphoric acid, thiab lub zog txo zog thiab monocarboxylic acid yam ntxwv ntawm hypophosphoric acid. Cov kev sib txawv no txiav txim siab lawv lub luag haujlwm hauv kev lag luam xws li electroplating, cov khoom siv hluavtaws, thiab kev kho dej: phosphorous acid yog tsim rau cov xwm txheej uas yuav tsum tau muaj kev sib npaug ntawm acidity thiab txo cov kev xav tau, phosphoric acid dominates muaj zog acid thiab kev sib koom tes daim ntaub ntawv, thaum hypophosphorous acid tsom rau cov txheej txheem nrog kev txo qis. Kev nkag siab txog cov kev sib txawv no tuaj yeem muab lub hauv paus kev tshawb fawb rau kev xaiv thiab kev ua kom zoo ntawm phosphorus-raws li tshuaj.
