Science, Tech, Math › Science Acetal Definition Share Flipboard Email Print This is the general structure of an acetal compound. Todd Helmenstine Science Chemistry Chemical Laws Basics Molecules Periodic Table Projects & Experiments Scientific Method Biochemistry Physical Chemistry Medical Chemistry Chemistry in Everyday Life Famous Chemists Activities for Kids Abbreviations & Acronyms Biology Physics Geology Astronomy Weather & Climate by Anne Marie Helmenstine, Ph.D. Dr. Helmenstine holds a Ph.D. in biomedical sciences and is a science writer, educator, and consultant. She has taught science courses at the high school, college, and graduate levels. Updated March 08, 2017 Definition: An acetal is an organic molecule where two separate oxygen atoms are single bonded to a central carbon atom.Acetals have the general structure of R2C(OR')2.An older definition of acetal had one at least one R group as a derivative of an aldehyde where R = H, but an acetal can contain derivatives of ketones where neither R group is a hydrogen. This type of acetal is called a ketal.Acetals that contain different R' groups are called mixed acetals. Acetal is also a common name for the compound 1,1-diethoxyethane.Examples: Dimethoxymethane is an acetal compound. Continue Reading