Trisodium orthoborate

Trisodium orthoborate
Names
	IUPAC name Trisodium orthoborate
	Other names Sodium, boric acid salt; Sodium orthoborate; Sodium borate;
Identifiers
CAS Number	14312-40-4 ;
3D model (JSmol)	Interactive image;
ChEMBL	ChEMBL38909 ;
ChemSpider	140167 ;
Gmelin Reference	117865
PubChem CID	159383;
CompTox Dashboard (EPA)	DTXSID1049776 ;
	InChI InChI=1S/BO3.3Na/c2-1(3)4;;;/q-3;3*+1 Key: BSVBQGMMJUBVOD-UHFFFAOYSA-N ;
	SMILES B([O-])([O-])[O-].[Na+].[Na+].[Na+];
Properties
Chemical formula	Na3BO3
Molar mass	127.78 g·mol−1
Density	1.73 g/cm3
Melting point	75 °C (167 °F; 348 K)
Boiling point	320 °C (608 °F; 593 K)
Hazards
	GHS labelling:
Pictograms
Signal word	Warning
Hazard statements	H319, H360, H361d, H412
Precautionary statements	P203, P264+P265, P273, P280, P305+P351+P338, P318, P337+P317, P405, P501
Related compounds
Related compounds	Borax; Sodium pentaborate; Disodium octaborate; Disodium enneaborate; Sodium metaborate;
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Trisodium borate is a chemical compound of sodium, boron, and oxygen, with formula Na₃BO₃, or (Na⁺)₃[BO₃]³⁻.^[3] It is a sodium salt of the orthoboric acid B(OH)₃.

The compound is also called trisodium orthoborate, sodium orthoborate, or just sodium borate. However, "sodium orthoborate" has been used also for a compound with formula Na₄B₂O₅, which would correspond to an equimolar mixture of sodium metaborate NaBO₂ and trisodium borate proper.^[4] and "sodium borate" is sometimes used in the generic sense, for a sodium salt with any of several other borate anions.

Preparation

Sodium carbonate Na₂CO₃ will react with sodium metaborate NaBO₂ or boric oxide B₂O₃ to form the orthoborate and carbon dioxide when heated between 600 and 850 °C:^[3]

NaBO₂ + Na₂CO₃ → Na₃BO₃ + CO₂

Difficult to obtain in pure form from melts.^[5]

Properties

Reactions

When dissolved in water, the orthoborate anion partially hydrolyzes into metaborate [BO₂]⁻ and hydroxide OH⁻:^[3]

[BO₃]³⁻ + H₂O ⇌ [BO₂]⁻ + 3 OH⁻

Electrolysis of a solution of sodium orthoborate generates sodium perborate at the anode.^[6] ^[7]

References

^ ^a ^b ^c "Trisodium borate" Product page in the World Of Chemicals website. Accessed on 2022-06-27.
^ "Boric acid, sodium salt". pubchem.ncbi.nlm.nih.gov.
^ ^a ^b ^c Pasupathy Rajan Subbaiyan (2003): "Study of Trisodium Borate Formation and Its Reaction with Green Liquor in Partial Autocausticizing". Masters Thesis, Western Michigan University.
^ Daniel L. Calabretta and Boyd R. Davis (2007) "Investigation of the anhydrous molten Na–B–O–H system and the concept: Electrolytic hydriding of sodium boron oxide species". Journal of Power Sources, volume 164, issue 2, pages 782-791. doi:10.1016/j.jpowsour.2006.11.023
^ G. W. Morey and H. E. Merwin (1936): "Phase Equilibrium Relationships in the Binary System, Sodium Oxide-Boric Oxide, with Some Measurements of the Optical Properties of the Glasses". Journal of the American Chemical Society, volume 58, issue 11, pages 2248–2254. doi:10.1021/ja01302a04
^ Wilfrid Gustav Polack (1915): "The anodic behaviour of alkaline borate and perborate solutions". Transactions of the Faraday Society, volume 10, pages 177-196. doi:10.1039/TF9151000177
^ Tanatar (1898): Zh. Pys. Chem., volume 26, page 132.