Boric acid

Boric acid

Names
IUPAC names Boric acid Trihydrooxidoboron
Other names Orthoboric acid, Boracic acid, Sassolite, Optibor, Borofax, Trihydroxyborane, Boron(III) hydroxide
Identifiers
CAS Number	10043-35-3 Y
3D model (Jmol)	Interactive image Interactive image
ChEBI	CHEBI:33118 Y
ChEMBL	ChEMBL42403 Y
ChemSpider	7346 Y
ECHA InfoCard	100.030.114
EC Number	233-139-2
E number	E284 (preservatives)
KEGG	D01089 Y
PubChem	7628
UNII	R57ZHV85D4 Y
InChI InChI=1S/BH3O3/c2-1(3)4/h2-4H Y Key: KGBXLFKZBHKPEV-UHFFFAOYSA-N Y InChI=1/BH3O3/c2-1(3)4/h2-4H Key: KGBXLFKZBHKPEV-UHFFFAOYAI
SMILES OB(O)O B(O)(O)O
Properties
Chemical formula	BH3O3
Molar mass	61.83 g·mol−1
Appearance	White crystalline solid
Density	1.435 g/cm3
Melting point	170.9 °C (339.6 °F; 444.0 K)
Boiling point	300 °C (572 °F; 573 K)
Solubility in water	2.52 g/100 mL (0 °C) 4.72 g/100 mL (20 °C) 5.7 g/100 mL (25 °C) 19.10 g/100 mL (80 °C) 27.53 g/100 mL (100 °C)
Solubility in other solvents	Soluble in lower alcohols moderately soluble in pyridine very slightly soluble in acetone
Acidity (pKa)	9.24, 12.4, 13.3
Magnetic susceptibility (χ)	-34.1·10−6 cm3/mol
Structure
Molecular shape	Trigonal planar
Dipole moment	Zero
Pharmacology
ATC code	S02AA03 (WHO) D08AD (WHO)
Hazards
Safety data sheet	See: data page
EU classification (DSD)	Xn
R-phrases	R60 R61
S-phrases	S53 S45
NFPA 704	0 2 0
Flash point	Non-flammable
Lethal dose or concentration (LD, LC):
LD50 (median dose)	2660 mg/kg, oral (rat)
Related compounds
Related compounds	Boron trioxide Borax
Supplementary data page
Structure and properties	Refractive index (n), Dielectric constant (εr), etc.
Thermodynamic data	Phase behaviour solid–liquid–gas
Spectral data	UV, IR, NMR, MS
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Y  (what is YN ?)
Infobox references

Boric acid, also called hydrogen borate, boracic acid, orthoboric acid and acidum boricum, is a weak, monobasic Lewis acid of boron often used as an antiseptic, insecticide, flame retardant, neutron absorber, or precursor to other chemical compounds. It has the chemical formula H₃BO₃ (sometimes written B(OH)₃), and exists in the form of colorless crystals or a white powder that dissolves in water. When occurring as a mineral, it is called sassolite.

Boric acid, or sassolite, is found natively in its free state in some volcanic districts, for example, in the Italian region of Tuscany, the Lipari Islands and the US state of Nevada. In these volcanic settings it issues, mixed with steam, from fissures in the ground. It is also found as a constituent of many naturally occurring minerals – borax, boracite, ulexite (boronatrocalcite) and colemanite. Boric acid and its salts are found in seawater. It is also found in plants, including almost all fruits.

Boric acid was first prepared by Wilhelm Homberg (1652–1715) from borax, by the action of mineral acids, and was given the name sal sedativum Hombergi ("sedative salt of Homberg"). However borates, including boric acid, have been used since the time of the Greeks for cleaning, preserving food, and other activities.