Sodium perborate

Sodium perborate
Sodium perborate
Identifiers
CAS number 7632-04-4 YesY, 10332-33-9 (monohydrate) YesY, 10486-00-7 (tetrahydrate) YesY
PubChem 5460514
ChemSpider 4574023 YesY
UNII Y52BK1W96C YesY
EC number 231-556-4
UN number 1479
ChEBI CHEBI:30178 YesY
RTECS number SC7350000
Jmol-3D images Image 1
Properties
Molecular formula NaBO3·nH2O
Molar mass 99.815 g/mol (monohydrate);
153.86 g/mol (tetrahydrate)
Appearance white powders
Hazards
MSDS ICSC 1046
NFPA 704
NFPA 704.svg
1
1
0
Flash point non-flammable
 YesY perborate (verify) (what is: YesY/N?)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Sodium perborate (PBS) is a white, odorless, water-soluble chemical compound with the chemical composition NaBO3. It crystallizes as the monohydrate, NaBO3·H2O, trihydrate, NaBO3·3H2O and tetrahydrate, NaBO3·4H2O.[1] The monohydrate and tetrahydrate are the commercially important forms.[1] The elementary structural unit of sodium perborates is a dimer anion B2O4(OH)42–, in which two boron atoms are joined by two peroxo bridges in a chair-shaped 6-membered ring, and the simplistic NaBO3·nH2O-type formulas are just a convenient way to express the average chemical composition.

Contents

Preparation and chemistry

Sodium perborate is manufactured by reaction of disodium tetraborate pentahydrate, hydrogen peroxide, and sodium hydroxide.[1] The monohydrate form dissolves better than the tetrahydrate and has higher heat stability; it is prepared by heating the tetrahydrate. Sodium perborate undergoes hydrolysis in contact with water, producing hydrogen peroxide and borate.[1]

Structure

Unlike sodium percarbonate and perphosphate, the sodium perborate is not simply an adduct with hydrogen peroxide, and it does not contain individual and does not contain a BO3 ions.[2] Rather, there is a cyclic dimer anion B2O4(OH)42–, in which two boron atoms are joined by two peroxo bridges in a chair-shaped 6-membered ring.[3] This makes the substance more stable, and safer for handling and storage. The formula of the sodium salt is thus Na2H4B2O8.[1]

Uses

It serves as a source of active oxygen in many detergents, laundry detergents, cleaning products, and laundry bleaches.[1] It is also present in some tooth bleaching formulas. It is used as a bleaching agent for internal bleaching of a non vital root treated tooth. The sodium perborate is placed inside the tooth and left in place for an extended period of time to allow it to diffuse into the tooth and bleach stains from the inside out. It has antiseptic properties and can act as a disinfectant. It is also used as a "disappearing" preservative in some brands of eye drops.

Sodium perborate is a less aggressive bleach than sodium hypochlorite, causing less degradation to dyes and textiles. Borates also have some non-oxidative bleaching properties.

Sodium perborate releases oxygen rapidly at temperatures over 60°C. To make it active at lower temperatures (40–60 °C), it has to be mixed with a suitable activator, typically tetraacetylethylenediamine (TAED).

See also

References

  1. ^ a b c d e f B.J Brotherton Boron: Inorganic Chemistry Encyclopedia of Inorganic Chemistry (1994) Ed. R. Bruce King, John Wiley & Sons ISBN 0-471-93620-0
  2. ^ Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Oxford: Butterworth-Heinemann. ISBN 0080379419. 
  3. ^ Carrondo, M. A. A. F. de C. T.; Skapski, A. C. (1978). "Refinement of the X-ray crystal structure of the industrial bleaching agent disodium tetrahydroxo-di-μ-peroxo-diborate hexahydrate, Na2[B2(O2)2(OH)4]·6H2O". Acta Crystallogr B34: 3551. doi:10.1107/S0567740878011565. 

External links


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Look at other dictionaries:

  • sodium perborate — n a white crystalline hydrated powder NaBO3·4H2O used as an oral antiseptic * * * a compound, NaBO3·4H2O, prepared by interaction of boric acid or sodium borate with sodium or hydrogen peroxide. It is an antiseptic, used in 2 per cent solution as …   Medical dictionary

  • sodium perborate — n. a white, odorless, crystalline compound, NaBO3·4H2O, used chiefly as a bleaching and oxidizing agent and in germicides, deodorants, etc …   English World dictionary

  • sodium perborate — noun : either of two crystalline or powdery substances that are compounds of sodium metaborate with hydrogen peroxide and are used chiefly as bleaching agents and oxidizing agents and in mouthwashes and dentifrices: a. or sodium perborate… …   Useful english dictionary

  • sodium perborate — natrio perboratas statusas T sritis chemija formulė NaBO₃ atitikmenys: angl. sodium perborate rus. натрий надборнокислый; натрия перборат ryšiai: sinonimas – natrio trioksoboratas …   Chemijos terminų aiškinamasis žodynas

  • sodium perborate monohydrate — noun see sodium perborate …   Useful english dictionary

  • sodium perborate tetrahydrate — noun see sodium perborate …   Useful english dictionary

  • sodium perborate — Chem. a white, crystalline, water soluble solid, NaBO2·3H2O or NaBO3·4H2O, used chiefly as a bleaching agent and antiseptic. Also called perborax. * * * …   Universalium

  • Perborate de sodium — Dimère de pe …   Wikipédia en Français

  • Sodium percarbonate — Sodium percarbonate …   Wikipedia

  • Sodium fluoride — IUPAC name Sodium fluoride …   Wikipedia

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