Cov lus" anhydride yog acidic oxide" yog muaj tseeb nyob rau hauv ib tug ntau yam. Anhydride yog tsim los ntawm lub cev qhuav dej acid, thaum acidic oxide yog oxide uas cuam tshuam nrog alkali los ua ntsev thiab dej. Conceptually, ob qhov tsis sib npaug. Hauv tshuaj lom neeg inorganic, acid anhydrides yog tsim los ntawm cov kua qaub ua kom lub cev qhuav dej, thiab lawv feem ntau yog cov oxides, yog li ob qho tuaj yeem sib npaug, tab sis hauv cov organic chemistry, ntau cov organic acids yuav tsis oxides tom qab lub cev qhuav dej, xws li: cov kua qaub acetic acid (CH3COOH) lub cev qhuav dej rau tsim cov kab mob acetic anhydride ((C4H6O3, (CH3CO) 2O), yog li nws tsis tuaj yeem tiv thaiv acidic oxide.
Kev ntsuas dej ntawm cov acids:
H2SO4 → SO3
H2SO3 → SO2
H2CO3 → CO2
H3PO4 → P2O5
HNO3 → N2O5
HNO2 → N2O3
CH3COOH → (CH3CO) 2O
H3PO3 → P2O3