Science, Tech, Math › Science Tetrahedral Definition - Chemistry Glossary Share Flipboard Email Print A tetrahedral molecule has a central atom with four bonds, forming a tetrahedron. ForestMavka / Getty Images Science Chemistry Basics Chemical Laws 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. Chemistry Expert Ph.D., Biomedical Sciences, University of Tennessee at Knoxville B.A., Physics and Mathematics, Hastings College 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. our editorial process Facebook Facebook Twitter Twitter Anne Marie Helmenstine, Ph.D. Updated September 04, 2019 Tetrahedral is a descriptor of the geometry of a molecule in which a central atom forms four bonds which are directed toward the corners of a regular tetrahedron. Tetrahedral geometry forms a solid with four vertices and four sides, all of which are equilateral triangles. Examples of tetrahedral molecules include methane (CH4) and the ammonium ion (NH4+). The bond angle for both methane and ammonium is 109.4˚.