Sodium sesquicarbonate
| Identifiers | |
|---|---|
| 3D model (JSmol) | |
| ECHA InfoCard | 100.007.802 | 
| EC Number | 
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| PubChem CID | |
| UNII | |
| CompTox Dashboard (EPA) | |
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| Properties | |
| Na3H(CO3)2·2H2O | |
| Appearance | white, needle-like | 
| Density | 2.112 g/cm3 (dihydrate) | 
| dihydrate 13 g/100 mL (0 °C) 42 g/100 mL (100 °C) | |
| Refractive index (nD) | 1.5073 (dihydrate) | 
| 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.
Due to concerns about the toxicity of borax which was withdrawn as a cleaning and laundry product, sodium sesquicarbonate is sold in the European Union (EU) as "Borax substitute". It is also known as one of the E number food additives E500(iii).