Sciencemadness Discussion Board

Potassium, ammonium or sodium dichromate - HDPE containers advisable?

dangerous amateur - 28-10-2020 at 11:14

I got a sample of each from a friend and (temporarily?) store it in HDPE.

I know that at least the ammonium salt is kind of aggressive...

Storing this maybe a long time, what kind of vessel would you use for this?
Is glass necessary?

I'm thinking of permeation through the HDPE, contamination of the dichromate from attacked plastic ect.

valeg96 - 28-10-2020 at 14:17

They are fine, most are stored in PE containers.

Herr Haber - 28-10-2020 at 20:58

I do store them in HDPE but it's true that I've received Potassium Dichromate in an amber glass vials from sellers that otherwise would not hesitate to use ziploc bags for other chemicals.
After 3+ years the HDPE shows no degradation or color whatsoever but it's true I always go for the best quality for all my containers.

Something I learned with computers. Pay more now, worry less longer.

I wouldnt worry..

woelen - 28-10-2020 at 23:31

The potassium and ammonium salt can be stored in nearly any container, even in plastic bags. They are perfectlty dry compounds, not hygroscopic. Just assure that no dust can reach the chemicals.

The sodium salt is very hygroscopic and if not stored in a perfectly sealed container it will quickly become really wet. That is when it becomes corrosive. The wet mud contains dissolved dichromate, which will slowly attack many plastics (dissolved dichromate is somewhat acidic and strongly oxidizing). I store my sodium dichromate in a glass jar with a very tight seal.