Schlenk Flasks
A Schlenk flask with a compromised tap costs you the reaction, not just the glassware. These J Young Schlenk flasks pair borosilicate bodies with the greaseless taps the J Young name is known for, from $133.
Round bottom and cylindrical bodies from $133 to $300
Fine thread PTFE, glass, and O-ring tap options
Cold finger and finger tube variants for sublimation and small-scale work
Joints and taps matched to the J Young Schlenk lines in the same collection
Models suitable for…
Air-sensitive synthesis
Reagent and catalyst storage
Sublimation purification
J Young Schlenk flasks at a glance
What is this collection?
A range of J Young Schlenk flasks and Schlenk tubes covering round bottom and cylindrical bodies, with fine thread PTFE taps, traditional glass taps, and O-ring taps including a high performance variant. The collection also includes plain arm flasks, a round bottom flask with cold finger, and a finger Schlenk tube. Prices run from $133 to $300, with replacement Schlenk caps at $30.
Who is it for?
Synthetic chemists in organometallic, catalysis, inorganic, and polymer labs who handle air-sensitive or moisture-sensitive compounds, plus lab managers stocking shared glassware drawers and teaching labs running air-free technique courses.
What does it do?
A Schlenk flask holds your reaction or reagent under vacuum or inert gas. The sidearm connects to a Schlenk line so you can evacuate, backfill, and manipulate contents without exposing them to air, and the tap seals the flask for storage off the line.
What problems does it solve?
Oxygen and moisture killing reagents during handling and storage. Grease from traditional stopcocks contaminating products and spectra. Mismatched joints between flasks and the rest of your line. Replacing broken glassware mid-project without switching joint standards.
What are your next steps?
Pick the body shape for your application, choose a tap type, and confirm the joint on the product page matches your line and adaptors. The selection guide below walks through the choices.
What can you learn on this page?
- What a Schlenk flask is and how it's used.
- Round bottom or cylindrical: choosing a body shape.
- Fine thread, glass, or O-ring: choosing a tap.
- How to choose the right Schlenk flask.
- Where these Schlenk flasks are used.
- Schlenk flask frequently asked questions.
What is a Schlenk flask and how is it used?
A Schlenk flask is a reaction or storage vessel with a sidearm fitted with a tap. The sidearm connects to a Schlenk line, and the tap lets you switch the flask between vacuum, inert gas, and sealed states without ever opening the vessel to air.
That control supports the standard air-free operations:
- Evacuate and backfill with nitrogen or argon to establish an inert atmosphere before introducing sensitive reagents.
- Run reactions under inert gas with the flask connected to the line.
- Seal the tap and store air-sensitive compounds on the shelf, off the line.
- Degas solvents by freeze-pump-thaw directly in the flask.
The flask's main neck takes a ground glass joint, so you can fit septa, stoppers, condensers, or adaptors depending on the operation. Joint and capacity details are listed on each product page.
Round bottom or cylindrical. Choosing a body shape
Round bottom Schlenk flasks
are the classic reaction vessel shape. The geometry suits magnetic stirring, even heating in oil baths or heating mantles, and standard reaction workflows. The collection includes round bottom models with fine thread taps, glass key taps, and plain arms, plus a cold finger variant.
Cylindrical Schlenk flasks
often called Schlenk tubes, trade the reaction-friendly geometry for a slim profile that's easier to clamp, store in rows, and use for small-scale work and reagent storage. Most of the tap variety in this collection sits in the cylindrical range: fine thread taps with cone, socket, or B14 socket terminations, glass taps, and O-ring taps including the high performance model.
Two specialty bodies round out the collection…
The round bottom flask with cold finger ($198)
supports sublimation: the compound vaporizes under vacuum and condenses on the cooled finger as purified solid.
The finger Schlenk tube ($203) is a narrow finger-shaped vessel with a fast thread tap, suited to very small quantities.
Fine thread, glass, or O-ring and choosing a tap
The tap is where Schlenk flasks earn or lose their keep, and this collection covers three approaches.
Fine thread PTFE taps are the standard J Young greaseless design. Glass seals against PTFE with no grease, so there's nothing to contaminate your product and nothing for solvent vapors to dissolve. The fine thread gives gradual control when you open a flask to vacuum, which matters when the contents include volatile solvent.
Glass taps are the traditional greased stopcock. Some labs have an established grease regimen and prefer them; the glass key round bottom ($156) and glass tap cylindrical ($133) serve that preference at the lowest prices in the collection.
O-ring taps seal with an O-ring and pair with an O-ring ball joint cup connection. The standard model is $269 and the high performance variant is $300. Connection and sealing details are on the product pages.
If you're standardizing a lab, it’s practical to match tap types and joints across your flasks, manifold, and adaptors. Everything in this collection follows the same J Young standard as the Schlenk lines, taps, joints, and cone adaptors sold alongside it.
How to choose the right Schlenk flask
If your priority is... | Consider... |
Standard reactions with stirring and heating. | Round bottom with fine thread tap and socket ($216). |
Reagent storage and small-scale work in a slim body. | Cylindrical with fine thread tap ($145), or with B14 socket ($198) or cone ($169) terminations to match your adaptors. |
The lowest-cost entry into the collection. | Cylindrical with glass tap and cone ($133), if greased stopcocks suit your lab. |
Demanding sealing requirements. | Cylindrical O-ring tap models ($269 standard, $300 high performance). |
Sublimation purification. | Round bottom with plain arm and cold finger ($198). |
Very small quantities. | Finger Schlenk tube with fast thread tap ($203). |
A sidearm without its own tap, controlled at the line. | Round bottom plain arm ($183). |
Keep spare J Young Schlenk caps ($30) on hand. An uncapped joint is an open door for air and dust, and a missing cap shouldn't be the reason a flask sits unused.
Where are these Schlenk flasks used?
Organometallic and inorganic synthesis
Reactions and reagent handling where oxygen or moisture exposure decomposes the chemistry. The core application for the round bottom and cylindrical workhorses.
Catalyst storage
Sealed cylindrical flasks keep air-sensitive catalysts viable on the shelf between uses, without committing glovebox space.
Sublimation purification
The cold finger flask purifies solids that sublime under vacuum, a standard final purification for many organometallic compounds.
Teaching labs
Durable, standardized flasks for students learning Schlenk technique, with tap types matching what they'll use in research labs.
Schlenk flask frequently asked questions
The sidearm and tap. A regular round bottom flask has one neck and no built-in way to control its atmosphere. A Schlenk flask adds a tapped sidearm that connects to a Schlenk line, so you can evacuate it, fill it with inert gas, and seal it without opening the vessel.
Shape. Schlenk tube is the common name for the cylindrical form. Round bottom Schlenk flasks suit stirred, heated reactions; cylindrical ones suit storage, small-scale work, and tight clamping arrangements. The sidearm and tap work the same way on both.
Only on the glass tap models, which use a traditional greased stopcock. The fine thread and fast thread models seal glass against PTFE and run grease-free, which is the point of the J Young design: no grease in your product, your spectra, or your vacuum.
They're built for Schlenk line vacuum and standard reaction heating, with the usual glassware caveats: inspect for chips and star cracks before each use, and follow your lab's procedures for evacuated glassware. For oven drying, remove PTFE tap components first, since PTFE deforms at oven temperatures that borosilicate shrugs off.
Check the joint specification on the product page against your line, adaptors, and stoppers. Cone terminations are male joints, sockets are female, and the B14 socket model carries a 14 mm ground joint. Standardizing on the J Young collection keeps every connection compatible.
Familiarity and an established grease regimen, mostly. Labs that have run greased stopcocks for decades sometimes prefer to keep their technique consistent. For most new purchases, the greaseless fine thread taps are the default choice.
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