Cov qauv ntawm cawv

Lub melting thiab boiling cov ntsiab lus ntawm qis cawv yog ntau dua li cov hydrocarbons nrog tib tus naj npawb ntawm carbon atoms, uas yog tshwm sim los ntawm hydrogen daim ntawv cog lus ntawm cov cawv molecules. Cov txiaj ntsig kev sim qhia tau hais tias nws yuav siv li 21 txog 30KJ / mol rau hydrogen daim ntawv cog lus kom tawg, uas qhia tau hais tias nws tsis muaj zog ntau dua li interatomic (105 txog 418KJ / mol). Cawv nyob rau hauv lub xeev muaj zog, lub koom haum yog ruaj khov; Hauv cov kua hauv lub xeev, cov ntawv cog lus hydrogen yuav rov ua dua tom qab nws tawg; Txawm li cas los xij, hauv kev daws teeb meem ntawm gaseous lossis non-polar solvents, cawv molecules nyob deb ntawm ib leeg, thiab txhua tus cawv molecule tuaj yeem nyob sib nrug. Muaj ntau tshaj li ob txoj haujlwm hauv polyol molecule uas tuaj yeem tsim hydrogen bonds, yog li qhov kub ntawm qhov kub yog siab dua, xws li qhov kub ntawm ethylene glycol ntawm 197 degree C. Qhov sib xyaw ua ke ntawm hydrogen daim ntawv cog lus nce nrog kev nce siab, tab sis cov intramolecular. hydrogen bond tsis cuam tshuam los ntawm qhov concentration.
Methanol raug coj los ua piv txwv los qhia txog cov qauv ntawm cov cawv. Nyob rau hauv methanol molecule, daim ntawv cog lus ntev ntawm cov pa roj carbon-oxygen daim ntawv cog lus yog 143 teev, thiab lub kaum sab xis ntawm ∠COH yog 108.9 degree. Nws feem ntau ntseeg tau tias cov pa atom hauv cov dej cawv hydroxyl pawg yog sp³ tsis sib xws hybrid, thiab 6 electrons nyob rau sab nraud ntawm cov pa atom raug faib rau hauv 4 sp³ hybrid orbitals, ntawm 2 sp³ orbitals uas muaj tib lub electrons tsim carbon-oxygen. bonds nrog carbon atoms thiab hydrogen atoms, feem. Qhov seem ob khub ntawm unshared electrons nyob rau lwm ob sp³ orbitals. Lub hydrogen-oxygen daim ntawv cog lus thiab ob khub ntawm unshared electrons ntawm oxygen yog nyob rau hauv ib tug ntoo khaub lig-dominant conformation nrog peb CH bonds ntawm methyl pawg.