most common compound on earth
Submit. Â· just now. Report Abuse. Water (H2O) is the most abundant compound *ON* the Earth. But while I'm answering, here are free (!) bonus answers: Silicon dioxide (SiO2) is the most abundant compound *IN* Earth's crust (what's below that has not been accurately quantified, only estimated).ubmit. Â· just now. Report Abuse. Water (H2O) is the most abundant compound *ON* the Earth. But while I'm answering, here are free (!) bonus answers: Silicon dioxide (SiO2) is the most abundant compound *IN* Earth's crust (what's below that has not been accurately quantified, only estimated).