Borax

Borax
Names
	IUPAC name disodium;3,7-dioxido-2,4,6,8,9-pentaoxa-1,3,5,7-tetraborabicyclo[3.3.1]nonane;decahydrate
	Other names Borax decahydrate; Sodium borate decahydrate; Sodium tetraborate decahydrate; Sodium tetrahydroxy tetraborate hexahydrate;
Identifiers
CAS Number	1303-96-4 ;
3D model (JSmol)	Interactive image;
ChEBI	CHEBI:86222;
ChEMBL	ChEMBL3833375;
ChemSpider	17339255;
EC Number	603-411-9;
E number	E285 (preservatives)
KEGG	D03243;
PubChem CID	16211214;
RTECS number	VZ2275000;
UNII	91MBZ8H3QO;
CompTox Dashboard (EPA)	DTXSID101014358 ;
	InChI InChI=1S/B4O7.2Na.10H2O/c5-1-7-3-9-2(6)10-4(8-1)11-3;;;;;;;;;;;;/h;;;101H2/q-2;2+1;;;;;;;;;; Key: CDMADVZSLOHIFP-UHFFFAOYSA-N; InChI=1/B4O7.2Na.10H2O/c5-1-7-3-9-2(6)10-4(8-1)11-3;;;;;;;;;;;;/h;;;101H2/q-2;2+1;;;;;;;;;; Key: CDMADVZSLOHIFP-UHFFFAOYAP;
	SMILES [Na+].[Na+].O0B(O)O[B-]1(O)OB(O)O[B-]0(O)O1.O.O.O.O.O.O.O.O;
Properties
Chemical formula	Na2B4O5(OH)4·8H2O
Molar mass	381.36 g·mol−1
Appearance	White or colorless crystalline solid
Density	1.73 g/cm3 (decahydrate, solid)
Melting point	743 °C (1,369 °F; 1,016 K) (anhydrous); 75 °C (decahydrate, decomposes)
Boiling point	1,575 °C (2,867 °F; 1,848 K) (anhydrous)
Solubility in water	31.7 g/L
Magnetic susceptibility (χ)	−85.0·10−6 cm3/mol (anhydrous)
Refractive index (nD)	n1=1.447, n2=1.469, n3=1.472 (decahydrate)
Structure
Crystal structure	Monoclinic, mS92, No. 15
Space group	C2/c
Point group	2/m
Lattice constant	a = 1.1885 nm, b = 1.0654 nm, c = 1.2206 nm α = 90°, β = 106.623°°, γ = 90°
Lattice volume (V)	1.4810 nm3
Formula units (Z)	4
Pharmacology
ATC code	S01AX07 (WHO)
Hazards
	GHS labelling:
Pictograms
Hazard statements	H360
Precautionary statements	P201, P308+P313
NFPA 704 (fire diamond)	1 0 0
	NIOSH (US health exposure limits):
PEL (Permissible)	none
REL (Recommended)	TWA 1 mg/m3 (anhydrous and pentahydrate); TWA 5 mg/m3 (decahydrate)
IDLH (Immediate danger)	N.D.
Related compounds
Other anions	Sodium aluminate
Other cations	Lithium tetraborate
Related compounds	Boric acid, sodium perborate
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Borax (also referred to as sodium borate, tincal (/ˈtɪŋkəl/) and tincar (/ˈtɪŋkər/)) is a salt (ionic compound) normally encountered as a hydrated borate of sodium, with the chemical formula Na₂H₂₀B₄O₁₇.^[1]^[a] Borax mineral is a crystalline borate mineral that occurs in only a few places worldwide in quantities that enable it to be mined economically.

Borax can be dehydrated by heating into other forms with less water of hydration. The anhydrous form of borax can also be obtained from the decahydrate or other hydrates by heating and then grinding the resulting glasslike solid into a powder. It is a white crystalline solid that dissolves in water to make a basic solution due to the tetraborate anion.

Borax is commonly available in powder or granular form and has many industrial and household uses, including as a pesticide, as a metal soldering flux, as a component of glass, enamel, and pottery glazes, for tanning of skins and hides, for artificial aging of wood, as a preservative against wood fungus, as a food additive, and as a pharmaceutic alkalizer. In chemical laboratories it is used as a buffering agent.^[1]^[8]

The terms tincal and tincar refer to the naturally occurring borax historically mined from dry lake beds in various parts of Asia.^[9]

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