Hello!
I have a problem with Na2S·9H2O. A half of year ago it was a white wet powder (like a melted sugar) and now, when I have opened the jar I have found there a black liquid with a gray precipitate. What is happen with it and is it possible to repare it?
Thanks.
It may sound weird but my samples with sulfur get molded and have a green precipitants in them.
Molded? Seriously? But probably in Brazil it is common situation: molded samples, samples eaten by ants..:) Anyway, for me I think it will be easier to buy a new compound.
Thanks.
Sodium sulfide is expected to undergo hydrolysis due to moisture uptake from humid air: (i) Na2S + H2O ⇌ NaOH + NaHS; (ii) NaHS + H2O ⇌ NaOH + H2S; (i + ii) Na2S + 2H2O ⇌ 2NaOH + H2S. Also carbonation of Na2S can occur owing to air exposure: (iii) Na2S + H2O + CO2 ⇌ Na2CO3 + H2S; (iv) Na2S + 2NaOH + 2CO2 ⇌ 2Na2CO3 + H2S; besides that of NaOH. Corrosion of the container may perhaps result, possibly leaching out metallic cations, what may originate sulfide precipitate(s). If the container is of amber glass, ferrous iron could conceivably be leached out. Ferrous sulfide precipitate may appear black or dark grey. Further air exposure can lead to sulfide oxidation, what may result in a variety of species, such as Na2S2, Na2S2O3, Na2SO3, and Na2SO4.
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