Round-bottom flask

A round-bottom flask is featured prominently on the logo of the OPCW, the implementing body for the Chemical Weapons Convention.

[2] The round bottoms on these types of flasks allow more uniform heating and/or boiling of liquid.

This flask shape is also more resistant to fracturing under vacuum, as a sphere more evenly distributes stress across its surface.

Round-bottom flasks are often used to contain chemical reactions run by chemists, especially for reflux set-ups and laboratory-scale synthesis.

In the United States, it is illegal for an individual to possess, manufacture, buy, or sell a three neck round bottom flask while knowing, suspecting or intending the flask's purpose to be the manufacture of illegal or controlled substances.

It is not illegal, however to possess, manufacture, buy or sell a three neck round bottom flask for legal activities.