Covalent hom hydrides

Covalent hydrides, tseem hu ua molecular hydrides. Tsim los ntawm hydrogen thiab IIIA-VIIa pawg ntsiab lus. Cov hydrides tsim nrog IIIA pawg ntsiab lus yog electron deficient compounds thiab polymeric hydrides, xws li ethylborane B2H6, aluminium hydride (AlH3) n, thiab lwm yam. Lub thermal stability ntawm ntau yam covalent hydrides txawv heev. Lead hydride PbH4 thiab bismuth hydride BiH3 muaj zog decompose nyob rau hauv chav tsev kub, thaum hydrogen fluoride thiab dej hardly decompose thaum rhuab mus rau 1000 degree. Covalent hydrides kuj muaj qhov txo qis, raws li tus lej oxidation ntawm hydrogen yog +1, thiab nws qhov txo qis yog nyob ntawm qhov tsis muaj peev xwm ntawm hluav taws xob ntawm lwm yam Rn. Feem ntau hais lus, kev txo qis ntawm tib tsev neeg nce los ntawm sab saum toj mus rau hauv qab, thaum qhov txo qis ntawm sab laug mus rau sab xis hauv tib lub voj voog, piv txwv li:
4NH3+5O2 → 4NO+6H2O
2PH3+4O2 → P2O5+3H2O
2H2S+3O2 → 2SO2+2H2O
Tus cwj pwm ntawm covalent hydrides hauv dej yog qhov nyuaj. Feem ntau pom li:
Tsim muaj zog acids: HCl, HBr, HI;
Tsim cov acids tsis muaj zog: HF, H2S, H2Se, H2Te;
Alkaline tsim: NH3;
Hydrolysis tso tawm cov pa roj hydrogen: B2H6, SiH4;
Tsis cuam tshuam nrog dej: CH4, PH3, AsH3, GeH4, SnH4, SbH3.
Lub peev xwm ntawm hydride RHn muab cov protons feem ntau muaj feem xyuam rau cov electronegativity thiab vojvoog ntawm R. Cov acidity nce ntawm sab laug mus rau sab xis thaum tib lub voj voog raws li electronegativity ntawm R nce; Hauv tib tsev neeg, qhov nce hauv acidity los ntawm sab saum toj mus rau hauv qab yog txiav txim siab los ntawm qhov sib npaug ntawm qhov nce hauv lub vojvoog ntawm R. Lub zog ntawm acidity thiab alkalinity yog txiav txim siab los ntawm tag nrho lub zog cuam tshuam hauv lub voj voog thermochemical ntawm hydride ionization ntawm H + protons. hauv dej