Tetraboric acid

Tetraboric acid
Names
	IUPAC name 3,7-Dihydroxy-2,4,6,8,9-pentaoxa-1,3,5,7-tetraborabicyclo[3.3.1]nonane; Pyroboric acid;
Identifiers
CAS Number	12447-38-0;
3D model (JSmol)	Interactive image;
ChemSpider	450911 ;
PubChem CID	516845;
CompTox Dashboard (EPA)	DTXSID801014359 ;
	InChI InChI=1S/B4H2O7/c5-1-9-3(7)11-4(8)10-2-6/h7-8H Key: RTANKYMJXZNJGQ-UHFFFAOYSA-N ;
	SMILES OB(OB=O)OB(O)OB=O;
Properties
Chemical formula	B4H2O7
Molar mass	157.25 g·mol−1
Appearance	white solid
Melting point	236 °C (457 °F; 509 K)
Conjugate base	Tetraborate
Hazards
	GHS labelling:
Signal word	Warning
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Tetraboric acid or pyroboric acid is a chemical compound with empirical formula H₂B₄O₇. It is a colourless water-soluble solid formed by the dehydration or polymerization boric acid.

Tetraboric acid is formally the parent acid of the tetraborate anion [B₄O₇]²⁻.