An Erlenmeyer flask, also known as a conical flask ( British English ) or a titration flask, is a type of laboratory flask which features a flat bottom, a conical body, and a cylindrical neck. It is named after the German chemist Emil Erlenmeyer (1825–1909), who created it in 1860.
Erlenmeyer flasks have wide bases, with sides that taper upward to a short vertical neck. They may be graduated, and often spots of ground glass or enamel are used where they can be labeled with a pencil. It differs from the beaker in its tapered body and narrow neck. Depending on the application, they may be constructed from glass or plastic, in a wide range of volumes.
The mouth of the Erlenmeyer flask may have a beaded lip that can be stopped or covered. Alternatively, the neck may be fitted with ground glass or other connector for use with more specialized stoppers or attachment to other apparatus. A Büchner flask is a common design modification used for filtration under vacuum.
Pyrex (trademarked as PYREX) is a brand introduced by Corning Inc. in 1908 for a line of clear, low-thermal-expansion borosilicate glass used for laboratory glassware.
Borosilicate glass is a type of glass with silica and boron trioxide as the main glass-forming constituents. Borosilicate glasses are known for having very low coefficients of thermal expansion (~3 × 10 −6 K −1 at 20 °C), making them resistant to thermal shock, more so than any other common glass.