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Chemistry Forums for Students => Inorganic Chemistry Forum => Topic started by: awais on July 13, 2006, 04:43:40 AM

Title: How to prepare Na2S4
Post by: awais on July 13, 2006, 04:43:40 AM

Hi Guys

Does anybody know about the preparation of sodium tetrasulfide (Na2S4) ??

Title: Re: How to prepare Na2S4
Post by: woelen on July 13, 2006, 05:25:35 AM

Na2S4 as a pure chemical is very hard to prepare. I even doubt whether this is available even at commercial supply houses.

What is available is something with empirical formula Na2Sx, with x around 3. This material, however, is a mix of polysulfides Na2S2, Na2S3, Na2S4, Na2S5 (and maybe higher???). Such a mix can be made fairly easily by yourself.

Dissolve as much of Na2S in water. Add solid finely powdered sulphur to this and heat until no more sulphur can be dissolved. The liquid by then will be intensely colored brown. Careful evaporation will give you the dry polysulfide mix. Commercially, the potassium compound is sold as Liver of sulphur, and that mix has average formula K2S3.

Why do you need specifically Na2S4? Isn't a mix of polysulpides suitable for your purpose?