Trisodium phosphate

Trisodium phosphate

Names
IUPAC name Trisodium phosphate
Other names Sodium phosphate tribasic
Identifiers
CAS Number	7601-54-9 Y 10101-89-0 (dodecahydrate) N
3D model (Jmol)	Interactive image
ChEBI	CHEBI:37583 Y
ChEMBL	ChEMBL363100 Y
ChemSpider	22665 Y
ECHA InfoCard	100.122.790
EC Number	231-509-8
KEGG	D09000 Y
PubChem	24243
RTECS number	TC9575000 V10XX01 (WHO) (32P)
UNII	SX01TZO3QZ N
InChI InChI=1S/3Na.H3O4P/c;;;1-5(2,3)4/h;;;(H3,1,2,3,4)/q3*+1;/p-3 Y Key: RYFMWSXOAZQYPI-UHFFFAOYSA-K Y InChI=1/3Na.H3O4P/c;;;1-5(2,3)4/h;;;(H3,1,2,3,4)/q3*+1;/p-3 Key: RYFMWSXOAZQYPI-DFZHHIFOAM
SMILES [O-]P(=O)([O-])[O-].[Na+].[Na+].[Na+]
Properties
Chemical formula	Na3PO4
Density	2.536 g/cm3 (17.5 °C, anhydrous) 1.62 g/cm3 (20 °C, dodecahydrate)
Melting point	1,583 °C (2,881 °F; 1,856 K) (anhydrous) 73.4 °C (164.1 °F; 346.5 K) (dodecahydrate)
Boiling point	100 °C (212 °F; 373 K) (dodecahydrate) decomposes
Solubility in water	anhydrous: 5.4 g/100 mL (0 °C) 12 g/100 mL (20 °C) 14.5 g/100 mL (25 °C) 23.3 g/100 mL (40 °C) 94.6 g/100 mL (100 °C) dodecahydrate: 28.3 g/100 mL (20 °C)
Solubility	insoluble in ethanol, CS2
Basicity (pKb)	2.23
Structure
Crystal structure	Trigonal
Thermochemistry
Specific heat capacity (C)	665 J/mol·K (dodecahydrate)
Std molar entropy (So298)	224.7 J/mol·K (anhydrous) 660 J/mol·K (dodecahydrate)
Std enthalpy of formation (ΔfHo298)	-1935.5 kJ/mol (anhydrous) -5480 kJ/mol (dodecahydrate)
Gibbs free energy (ΔfG˚)	-1819 kJ/mol (anhydrous)
Pharmacology
ATC code	A06AD17 (WHO) A06AG01 (WHO) B05XA09 (WHO)
Hazards
Safety data sheet	ICSC 1178
GHS pictograms
GHS signal word	Danger
GHS hazard statements	H315, H318, H335
GHS precautionary statements	P261, P280, P305+351+338
EU classification (DSD)	Xi
R-phrases	R36/37/38
S-phrases	S26
NFPA 704	0 2 1
Flash point	Non-flammable
Related compounds
Other cations	Tripotassium phosphate Triammonium phosphate Trimagnesium phosphate
Related compounds	Monosodium phosphate Disodium phosphate
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

Trisodium phosphate (TSP) is the inorganic compound with the chemical formula Na₃PO₄. It is a white, granular or crystalline solid, highly soluble in water producing an alkaline solution. TSPs are used as cleaning agent, lubricant, food additive, stain remover and degreaser.

The item of commerce is often partially hydrated and may range from anhydrous Na₃PO₄, to the dodecahydrate, Na₃PO₄·12 H₂O. Most often found in white powder form, it can also be called trisodium orthophosphate or simply sodium phosphate.

Trisodium phosphate is produced by neutralization of phosphoric acid using sodium hydroxides, often with sodium carbonate. Carbonate can only produce disodium phosphate:

Trisodium phosphate was at one time extensively used in formulations for a variety of consumer grade soaps and detergents, and the most common use for trisodium phosphate has been in cleaning agents. The pH of a 1% solution is 12 (i.e., very basic), and the solution is sufficiently alkaline to saponify grease and oils. In combination with surfactants, TSP is an excellent agent for cleaning everything from laundry to concrete driveways. This versatility and low manufacturing price made TSP the basis for a plethora of cleaning products sold in the mid-20th century. TSP is still sold and used as a cleaning agent but since the late 1960s its use has diminished in the United States and many other parts of the world because, like many phosphate-based cleaners, it is known to cause extensive eutrophication of lakes and rivers once it enters a water system. Substitutes are generally not as effective.

TSP is commonly used after cleaning a surface with mineral spirits in order to remove hydrocarbon residues and may be used with household chlorine bleach in the same solution without hazardous reactions. This mixture is particularly effective for removing mildew, but is less effective at removing mold.