Borax

Borax (also referred to as sodium borate, tincal (/ˈtɪŋkəl/) and tincar (/ˈtɪŋkər/)) is a salt (ionic compound), a hydrated or anhydrous borate of sodium, with the chemical formula Na₂H₂₀B₄O₁₇.

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 Y
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;;;10*1H2/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;;;10*1H2/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

It is a colorless crystalline solid that dissolves in water to make a basic solution.

It 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, and as a pharmaceutic alkalizer. In chemical laboratories, it is used as a buffering agent.

The terms tincal and tincar refer to native borax, historically mined from dry lake beds in various parts of Asia.