Antimony pentoxide

Antimony pentoxide

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Names
IUPAC name (dioxo-λ5-stibanyl)oxy-dioxo-λ5-stibane
Other names antimony(V) oxide
Identifiers
CAS Number	1314-60-9 Y
ChemSpider	14129 Y
Jmol 3D model	Interactive image
PubChem	14813
InChI InChI=1S/5O.2Sb Y Key: LJCFOYOSGPHIOO-UHFFFAOYSA-N Y InChI=1/5O.2Sb/rO5Sb2/c1-6(2)5-7(3)4 Key: LJCFOYOSGPHIOO-YOUOZQPQAC
SMILES O=[Sb](=O)O[Sb](=O)=O
Properties
Chemical formula	Sb2O5
Molar mass	323.517 g/mol
Appearance	yellow powdery solid
Density	3.78 g/cm3, solid
Melting point	380 °C (716 °F; 653 K) (decomposes)
Solubility in water	0.3 g/100 mL
Solubility	insoluble in nitric acid
Structure
Crystal structure	cubic
Thermochemistry
Specific heat capacity (C)	117.69 J/mol K
Std enthalpy of formation (ΔfHo298)	-1008.18 kJ/mol
Vapor pressure	{{{value}}}
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N verify (what is YN ?)
Infobox references

Antimony pentoxide (Sb₂O₅) is a chemical compound of antimony and oxygen. It always occurs in hydrated form, Sb₂O₅·nH₂O. It contains antimony in the +5 oxidation state.

Structure

Antimony pentoxide has the same structure as the B form of niobium pentoxide and can be derived from the rutile structure, with antimony coordinated by six oxygens in a distorted octahedral arrangement. The SbO₆ octahedra are corner- and edge-sharing.

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Sb coordination	edge sharing	corner sharing

Preparation

The hydrated oxide is prepared by hydrolysis of antimony pentachloride; or by acidification of potassium hexahydroxoantimonate(V). It may also be prepared by oxidation of antimony trioxide with nitric acid.

Uses

It finds use as a flame retardant in ABS and other plastics, a flocculant in the production of titanium dioxide and is sometimes used in the production of glass, paint and adhesives.

It is also used as an ion-exchange resin for a number if cations in acidic solution including Na⁺ (especially for their selective retentions); and as a polymerization and oxidation catalyst.

Properties and reactions

The hydrated oxide is insoluble in nitric acid, but dissolves in concentrated potassium hydroxide solution to give potassium hexahydroxoantimonate(V), KSb(OH)₆.

When heated at 700 °C the yellow hydrated pentoxide converts to an anhydrous white solid with a formula Sb₆O₁₃ containing both Sb(III) and Sb(V). Heating at 900 °C produces a white insoluble powder of Sb₂O₄ of both α and β forms. The β form consists of Sb(V) in octahedral interstices and pyramidal Sb(III) O₄ units. In these compounds, Sb(V) atom is octahedrally coordinated to six –OH groups.

The pentoxide can be reduced to antimony metal by heating with hydrogen or potassium cyanide.