Sodium sesquicarbonate

This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. Find sources: "Sodium sesquicarbonate" – news · newspapers · books · scholar · JSTOR (May 2017) (Learn how and when to remove this message)

Sodium sesquicarbonate

Identifiers
CAS Number	533-96-0 Y
3D model (JSmol)	Interactive image
ECHA InfoCard	100.007.802
EC Number	208-580-9
PubChem CID	10791
UNII	Y1X815621J Y
CompTox Dashboard (EPA)	DTXSID6049646
InChI InChI=1S/2CH2O3.3Na/c2*2-1(3)4;;;/h2*(H2,2,3,4);;;/q;;3*+1/p-3 Key: WCTAGTRAWPDFQO-UHFFFAOYSA-K
SMILES C(=O)(O)[O-].C(=O)([O-])[O-].[Na+].[Na+].[Na+]
Properties
Chemical formula	Na3H(CO3)2·2H2O
Appearance	white, needle-like
Density	2.112 g/cm3 (dihydrate)
Solubility in water	dihydrate 13 g/100 mL (0 °C) 42 g/100 mL (100 °C)
Refractive index (nD)	1.5073 (dihydrate)
Structure
Crystal structure	monoclinic (dihydrate)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Sodium sesquicarbonate (systematic name: trisodium hydrogendicarbonate) Na₃H(CO₃)₂ is a double salt of sodium bicarbonate and sodium carbonate (NaHCO₃ · Na₂CO₃), and has a needle-like crystal structure. However, the term is also applied to an equimolar mixture of those two salts, with whatever water of hydration the sodium carbonate includes, supplied as a powder.

The dihydrate, Na₃H(CO₃)₂ · 2H₂O, occurs in nature as the evaporite mineral trona.^[1]

Due to concerns about the toxicity of borax which was withdrawn as a cleaning and laundry product, sodium sesquicarbonate is sold in the European Union (EU) as "Borax substitute".^[2] It is also known as one of the E number food additives E500(iii).