Sodium pyrophosphate

Tetrasodium pyrophosphate
Names

IUPAC name Tetrasodium diphosphate
Other names Pyrophosphate, Sodium pyrophosphate, Tetrasodium pyrophosphate (anhydrous), TSPP
Identifiers
CAS Number	7722-88-5^Y 13472-36-1 (decahydrate)^Y
3D model (Jmol)	Interactive image
ECHA InfoCard	100.028.880
EC Number	231-767-1
PubChem	24403
RTECS number	UX7350000
InChI InChI=1S/4Na.H4O7P2/c;;;;1-8(2,3)7-9(4,5)6/h;;;;(H2,1,2,3)(H2,4,5, 6)/q4*+1;/p-4
SMILES [O-]P(=O)([O-])OP(=O)([O-])[O-].[Na+].[Na+].[Na+].[Na+]
Properties
Chemical formula	Na₄O₇P₂
Molar mass	265.90 g·mol⁻¹
Appearance	Colorless or white crystals
Odor	odorless
Density	2.534 g/cm³
Melting point	988 °C (1,810 °F; 1,261 K) (anhydrous) 79.5 °C (decahydrate)
Boiling point	decomposes
Solubility in water	2.61 g/100 mL (0 °C) 6.7 g/100 mL (25 °C) 42.2 g/100 mL (100 °C)
Solubility	insoluble in ammonia, alcohol
Refractive index (n_D)	1.425
Structure
Crystal structure	monoclinic (decahydrate)
Thermochemistry
Specific heat capacity (C)	241 J/mol K
Std molar entropy (S^o₂₉₈)	270 J/mol K
Std enthalpy of formation (Δ_fH^o₂₉₈)	-3166 kJ/mol
Gibbs free energy (Δ_fG˚)	-3001 kJ/mol
Hazards
Flash point	Non-flammable
US health exposure limits (NIOSH):
PEL (Permissible)	none
REL (Recommended)	TWA 5 mg/m³
IDLH (Immediate danger)	N.D.
Related compounds
Other anions	Trisodium phosphate Pentasodium triphosphate Sodium hexametaphosphate
Other cations	Tetrapotassium pyrophosphate
Related compounds	Disodium pyrophosphate
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N (what is ^YN ?)
Infobox references

Tetrasodium pyrophosphate, also called sodium pyrophosphate, tetrasodium phosphate or TSPP, is a colorless transparent crystalline chemical compound with the formula Na₄P₂O₇. It is a salt composed of pyrophosphate and sodium ions. Toxicity is approximately twice that of table salt when ingested orally. There is also a hydrated form, Na₄P₂O₇ · 10(H₂O).

Tetrasodium pyrophosphate is used as a buffering agent, an emulsifier, a dispersing agent, and a thickening agent, and is often used as a food additive. Common foods containing tetrasodium pyrophosphate include chicken nuggets, marshmallows, pudding, crab meat, imitation crab, canned tuna, and soy-based meat alternatives and cat foods and cat treats where it is used as a palatability enhancer.

In toothpaste and dental floss, tetrasodium pyrophosphate acts as a tartar control agent, serving to remove calcium and magnesium from saliva and thus preventing them from being deposited on teeth. Tetrasodium pyrophosphate is used in commercial dental rinses before brushing to aid in plaque reduction.

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Wikipedia