DalisAndy
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Storage of alkaline and alkaline earth metals
I know they need to be stored under mineral oil in glass containers. Will any mineral oil work? And how would I dry it?
[Edited on 25-8-2015 by DalisAndy]
Elements Collected: 19/81 (Excluding all radioactive, using placecard for those)
Any tips or good sources are welcome.
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Sulaiman
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I have only sodium, berylium and magnesium metal in these groups,
berylium and magnesium form oxide layers that substantially protect from further oxidation,
or at least oxidation proceeds very slowly.
I keep the berylium and magnesium in almost airtight tubes.
sodium must be protected from air or it will completely oxidise,
I keep mine under 'baby oil' which is a light mineral oil,
to dry the oil I suppose you could heat to >> 100C
or put a small piece of sodium in the oil and shake, release pressure, shake .....
the 'sacrificial' piece of sodium will get quite oxidised
and any reactive detergents etc. will also be neutralised
but the oil will be dry and your main stock will be well protected.
not my area, but for element collections I suspect that sealed glass ampules are required as all of the above only slow down oxidation.
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gdflp
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For element collections and long term storage, ampouling under an inert atmosphere or inert oil is the only option for these more reactive elements.
Some are more reactive than others, but over time(months to years) they will all begin to oxidize if left in mineral oil which is not ampouled. This
is due to the diffusion of oxygen into the mineral oil, which will slowly begin to react with the elements and will oxidize their surface.
Magnesium and beryllium are the exceptions, simply flushing the storage bottle with argon each time after opening will cause the oxidation rate to be
negligible, thus they do not require ampouling for general reagent purposes. If you want a nice sample for a element collection though, they will
need to be ampouled.
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byko3y
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I'm pretty sure that you actually can store sodium in a container that is relatively easy to open. One common problem with regular plastic caps is
that they are permeable for CO2 and O2 (PET, PP, PE, PTFE, and so on).
I would be glad to know what material can be used to seal the bottle completely gas-tight, while keeping it openable.
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gdflp
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You can, it will just start to oxidize slowly due to diffusion of air. You might be able to store sodium chunks under oil without significant
oxidation in a bottle such as this as long as you grease the stopcock.
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byko3y
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I'm not sure about what kind of grease can be completely non-permeable even under 0.5 atm of pressure (sodium absorbs gases).
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DalisAndy
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Would Lithium be an exception? Also wouldn't it be easier to fill the jar/vail completely up and then use a rubber ring with lid
Elements Collected: 19/81 (Excluding all radioactive, using placecard for those)
Any tips or good sources are welcome.
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Camroc37
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Quote: Originally posted by DalisAndy  | I know they need to be stored under mineral oil in glass containers. Will any mineral oil work? And how would I dry it?
[Edited on 25-8-2015 by DalisAndy] |
Any USP mineral oil works, just be sure there are no additives like perfume.
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diddi
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bunnings sells paraffin oil which works fairly well. I have all the Gr1 and Gr2 metals that are available and they are still fairly clean. Cs and Rb
are Argon only storage. argon is your only choice for pristine storage of the rest.
Paraffin can be heated to drive off water, btw
[Edited on 26-8-2015 by diddi]
Beginning construction of periodic table display
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ave369
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In my country, kerosene is usually used. Preferably lamp grade, not aviation grade. The bottle with kerosene and the metal is then stoppered as good
as possible.
Smells like ammonia....
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