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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Physical & Chemical properties

Appearance / physical state / colour

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Administrative data

Link to relevant study record(s)

Description of key information

Key study for Na2S (commercial form; type ca. 60 %):
• Smeykal, 2010: Solid, flakes, yellow
In a weight of evidence approach the appearance of the anhydrous compound is described in handbooks and secondary sources as follows:
• CRC, 2008: white cubic crystals
• Merck, 2006: cubic crystals or granules which discolour upon exposure to air
• HSDB, 2009:
-cubic crystals or granules
-clear crystals; yellow or brick-red lumps and flakes
-amorphous, yellow-pink or white crystal
-yellow or brick-red lumps or flakes or deliquescent crystals
-white to pink, crystalline solid
-odour of rotten eggs

Key value for chemical safety assessment

Physical state at 20°C and 1013 hPa:

Additional information

The expert judgment from Smeykal (2010) is considered reliable without restrictions.

Handbook data considered to be from a trusted source acc. to "ECHA, Guidance on information requirements and chemical safety assessment – Chapter R.7a: Endpoint specific guidance" and therefore, the description of sodium sulfide could be regarded as valid.

The hydrated, commercial form (ca. 60 % Na2S) is described as a solid, however forming yellow flakes.

In seven references the appearance of the anhydrous form of sodium sulfide is described as solid crystals, granules, lumps or flakes. Further the descriptions of the colour of the anhydrous form varies in the different references between clear, white, yellow, pink and red. The reason for the different shapes and colours observed may be the fact that the anhydrous form of the substance is very hygroscopic and not stable and therefore the crystal water content may vary between the described substances.