Vigreux column
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A Vigreux column is laboratory glassware used as a type of fractionating column for fractional distillations. It is usually attached to a still at the bottom, and to a condenser at the top using ground glass joints. With many indentations in the glass, it provides a greater surface area for partitioning between the liquid and vapor phases than a straight-walled column. Although it provides a larger surface area, it is not larger than the straight-walled column. It is much more expensive.