Sodium tartrate (Na₂C₄H₄O₆) is a salt used as an emulsifier and a binding agent in food products such as jellies, margarine, and sausage casings. As a food additive, it is known by the E number E335.

Sodium l-tartrate^[1]

Names
IUPAC name disodium (2R,3R)-2,3-dihydroxybutanedioate
Other names Sal tartar; Disodium tartrate; Bisodium tartrate; Sodium l-(+)-tartrate; E335
Identifiers
CAS Number	868-18-8 (anhydrous) Y 6106-24-7 (dihydrate) Y
3D model (JSmol)	Interactive image
ChemSpider	12786 Y
PubChem CID	13355
UNII	QTO9JB4MDD Y DIA7C37AOW (dihydrate) Y
CompTox Dashboard (EPA)	DTXSID1028021
InChI InChI=1S/C4H6O6.2Na/c5-1(3(7)8)2(6)4(9)10;;/h1-2,5-6H,(H,7,8)(H,9,10);;/q;2*+1/p-2 Y Key: HELHAJAZNSDZJO-UHFFFAOYSA-L Y InChI=1S/C4H6O6.2Na/c5-1(3(7)8)2(6)4(9)10;;/h1-2,5-6H,(H,7,8)(H,9,10);;/q;2*+1/p-2 Key: HELHAJAZNSDZJO-NUQVWONBAO Key: HELHAJAZNSDZJO-UHFFFAOYSA-L
SMILES [Na+].[Na+].O=C([O-])C(O)C(O)C([O-])=O
Properties
Chemical formula	C4H4Na2O6 (anhydrous) C4H8Na2O8 (dihydrate)
Molar mass	194.051 g/mol (anhydrous) 230.082 g/mol (dihydrate)
Appearance	white crystals
Density	1.545 g/cm3 (dihydrate)
Solubility in water	soluble
Solubility	insoluble in ethanol
Pharmacology
ATC code	A06AD21 (WHO)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N verify (what is YN ?) Infobox references

Because its crystal structure captures a very precise amount of water, it is also a common primary standard for Karl Fischer titration, a common technique to assay water content.