Science, Tech, Math › Science What Is a Wedge and Dash Projection in Chemistry? Definition and Example Share Flipboard Email Print Ben Mills / Wikimedia Commons / Public Domain Science Chemistry Molecules Basics Chemical Laws 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 November 14, 2019 A wedge and dash projection is a drawing, a means of representing a molecule in which three types of lines are used in order to represent the three-dimensional structure: Solid lines to represent bonds that are in the plane of the paperDashed lines to represent bonds that extend away from the viewerWedge-shaped lines to represent bonds oriented facing the viewer Although there is no hard-and-fast rule for drawing a wedge and dash structure, most people find it easiest to visualize the three-dimensional shape of a molecule if the pair of bonds in the same plane as the paper is drawn next to each other, and the bonds in front of and behind the plane are also drawn next to each other (as in the example shown). Although the wedge-and-dash is the most common method of representing molecules in 3D, there are other diagrams you may encounter, including the sawhorse diagram and Newman projections.