Registration Dossier
Registration Dossier
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EC number: 240-778-0 | CAS number: 16721-80-5
Appearance / physical state / colour
Administrative data
Link to relevant study record(s)
Description of key information
Key study for NaHS (commercial form; type ca. 72 %):
• 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: colourless rhombohedral crystals
• Merck, 1996/2006: rhombohedric-cubic crystals; white to colourless with an odour like hydrogen sulfide
Key value for chemical safety assessment
- Physical state at 20°C and 1013 hPa:
- solid
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 hydrogensulfide could be regarded as valid.
The hydrated, commercial form (type ca. 72 % NaHS) is described as a solid, forming yellow flakes.
The appearance of the anhydrous form of sodium hydrogensulfide is described as solid crystals. Further the descriptions of the colours of the anhydrous form vary in the different references between colourless and white. The reason for the different colours observed may be the fact that the anhydrous compound is very hygroscopic and not stable and therefore the crystal water content may vary between the described substances.
Information on Registered Substances comes from registration dossiers which have been assigned a registration number. The assignment of a registration number does however not guarantee that the information in the dossier is correct or that the dossier is compliant with Regulation (EC) No 1907/2006 (the REACH Regulation). This information has not been reviewed or verified by the Agency or any other authority. The content is subject to change without prior notice.
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