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. 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 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˚. Continue Reading