ANTIMONY TRIOXIDE

Antimony(III) oxide is the inorganic compound with the formula Sb2O3. It is the most important commercial compound of antimony. It is found in nature as the minerals valentinite and senarmontite.[3] Like most polymeric oxides, Sb2O3 dissolves in aqueous solutions with hydrolysis.
Production and properties
Global production of antimony(III) oxide in 2012 was 130,000 tonnes, an increase from 112,600 tonnes in 2002. China produces the largest share followed by US/Mexico, Europe, Japan and 
South Africa and other countries (2%).

As of 2010, antimony(III) oxide was produced at four sites in EU27. It is produced via two routes, re-volatilizing of crude antimony(III) oxide and by oxidation of antimony metal. 
Oxidation of antimony metal dominates in Europe. Several processes for the production of crude antimony(III) oxide or metallic antimony from virgin material. The choice of process
 depends on the composition of the ore and other factors. Typical steps include mining, crushing and grinding of ore, sometimes followed by froth flotation and separation of the metal 
using pyrometallurgical processes (smelting or roasting) or in a few cases (e.g. when the ore is rich in precious metals) by hydrometallurgical processes. These steps do not take place 
in the EU but closer to the mining location.

Re-volatilizing of crude antimony(III) oxide
Step 1) Crude stibnite is oxidized to crude antimony(III) oxide using furnaces operating at approximately 500 to 1,000 °C. The reaction is the following:

2 Sb2S3 + 9 O2 → 2 Sb2O3 + 6 SO2
Step 2) The crude antimony(III) oxide is purified by sublimation.

Oxidation of antimony metal
Antimony metal is oxidized to antimony(III) oxide in furnaces. The reaction is exothermic. Antimony(III) oxide is formed through sublimation and recovered in bag filters. The size of
 the formed particles is controlled by process conditions in furnace and gas flow. The reaction can be schematically described by:
4 Sb + 3 O2 → 2 Sb2O3
Properties
Antimony(III) oxide is an amphoteric oxide, it dissolves in aqueous sodium hydroxide solution to give the meta-antimonite NaSbO2, which can be isolated as the trihydrate. Antimony(III)
 oxide also dissolves in concentrated mineral acids to give the corresponding salts, which hydrolyzes upon dilution with water.[5] With nitric acid, the trioxide is oxidized to 
antimony(V) oxide.

When heated with carbon, the oxide is reduced to antimony metal. With other reducing agents such as sodium borohydride or lithium aluminium hydride, the unstable and very toxic gas 
stibine is produced. When heated with potassium bitartrate, a complex salt potassium antimony tartrate, KSb(OH)2•C4H2O6 is formed.

Structure
The structure of Sb2O3 depends on the temperature of the sample. Dimeric Sb4O6 is the high temperature (1560 °C) gas. Sb4O6 molecules are bicyclic cages, similar to the related oxide
 of phosphorus(III), phosphorus trioxide. The cage structure is retained in a solid that crystallizes in a cubic habit. The Sb-O distance is 197.7 pm and the O-Sb-O angle of 95.6°.
 This form exists in nature as the mineral senarmontite.[9] Above 606 °C, the more stable form is orthorhombic, consisting of pairs of -Sb-O-Sb-O- chains that are linked by oxide bridges
 between the Sb centers. This form exists in nature as the mineral valentinite.

IUPAC name: Antimony(III) oxide
Other names: Antimony sesquioxide
Antimonous oxide
Flowers of Antimony
Identifiers
CAS Number: 1309-64-4

antimony trioxide
appropriate for use as a flame retardant synergist used in combination with a halogen compound. Many materials utilize its flame retardant properties including plastics, rubber,
paints, paper, textiles and electronics. Antimony trioxide is appropriate for use in polypropylene (PP), polyethylene (PE), ethylene propylene diene M-class rubber (EPDM), polyvinyl
chloride (PVC), high impact polystyrene (HIPS), acrylonitrile butadiene styrene (ABS), polyurethanes, phenolics, epoxies, and many others. Other applications of antimony trioxide include
a clarifying agent for glass, an opacifier for porcelain and enamel, and a white pigment

Antimony trioxide is formed by reacting antimony trichloride (SbCl3) with water. It is used in combination with some brominated flame retardants, and might also be used in conjunction 
with zinc borate, both within and outside the United States on commercial furniture, draperies, wall coverings, and carpets (R.C.Kidder, Flame Retardant Chemical Association, unpublished
 material, April 21, 1998). It is also used in enamels, glasses, rubber, plastics, adhesives, textiles, paper, and as a paint pigment (Budavari et al. 1989).

Antimony Trioxide
Antimony trioxide, also known as antimony oxide or Sb2O3, is the most widely produced compound of elemental antimony. The nations that produce the most antimony trioxide are China,
South Africa, Bolivia, Russia, Tajikistan, and Kyrgyzstan. Typical applications for antimony trioxide include flame retardant synergist for use in plastics, rubber, paints, paper, 
textiles, and electronics; polyethylene terephthalate polymerization catalyst; a clarifying agent for glass; an opacifier for porcelain and enamel; and a white pigment for paint. 
When used as a flame retardant, antimony trioxide is often used in combination with halogenated compounds. Antimony trioxide is used as a synergist to enhance the activity of the 
halogenated flame retardant. In the absence of antimony trioxide about twice as much halogenated compound would be needed to reach the same level of flame retardancy.

Antimony trioxide (Antimony oxide)
CAS Registry Number 1309-64-4

What is it?
Antimony trioxide is an industrial chemical and also occurs naturally in the environment.
How is it used?
In Canada, antimony trioxide is primarily used in combination with other compounds to provide flame retardant properties. Flame retardants used in household items such as mattress covers, furniture and carpets may contain antimony trioxide.
Antimony trioxide is also used in the manufacturing of a plastic material known as polyethylene terephthalate (PET).

Antimony trioxide (Antimony oxide)
CAS Registry Number 1309-64-4

What is it?
Antimony trioxide is an industrial chemical and also occurs naturally in the environment.
How is it used?
In Canada, antimony trioxide is primarily used in combination with other compounds to provide flame retardant properties. Flame retardants used in household items such as mattress covers, furniture and carpets may contain antimony trioxide.
Antimony trioxide is also used in the manufacturing of a plastic material known as polyethylene terephthalate (PET).

Sodium Antimonate
Sodium antimonate [15593-75-6], Na3SbO4, another antimony synergist of commercial importance, has an antimony content of 61–63 wt % and a bulk density of 39.4–46.4 kg/m3. Properties are given in Table 2. It is made by oxidizing antimony trioxide using sodium nitrate and caustic. It is a white powder and has a pH of around 9–11 when dissolved in water.

Sodium antimonate contains less antimony than either antimony trioxide or pentoxide and is thus less effective. However, its unique pH and low refractive index makes the antimonate
 the most desirable synergist for polymers that hydrolyze when processed with acidic additives or in polymers for which deep color tones are specified.

Antimony Oxide as a Primary Flame Retardant
Antimony oxide behaves as a condensed-phase flame retardant in cellulosic materials. It can be applied by impregnating a fabric with a soluble antimony salt followed by a second treatment that precipitates antimony oxide in the fibers. When the treated fabric is exposed to a flame, the oxide reacts with the hydroxyl groups of the cellulose (qv) causing them to decompose endothermically. The decomposition products, water and char, cool the flame reactions while slowing the production and volatilization of flammable decomposition products.

 Antimony Pentoxide

The second most widely used antimony synergist is antimony pentoxide [1313-60-9], Sb2O5, produced by the oxidation of the trioxide using either a peroxide or nitric acid. Antimony pentoxide is available as a nonpigmenting colloidal suspension in either water or organic media or as an agglomerated powder. It is insoluble in water, but soluble in hot concentrated acids. Properties of this unique flame retardant synergist are listed in Table.

Properties of Antimony Pentoxide and Sodium Antimonate
Property        Sb2O5        Na3SbO4
particle size, µm        0.03        1–2
surface area, m2/gm        50        
specific gravity        4.0        4.8
surface activity        weakly acidic        basic
refractive index, n20D        1.7        1.75
Submicrometer antimony pentoxide is primarily used to impart flame retardancy to fibers and fabrics. It can be added to the molten or dissolved polymer prior to forming the fiber. The antimony in this form can easily pass through the spinnerets without clogging the openings, whereas standard grades of antimony trioxide would rapidly clog the openings and necessitate frequent shutdowns for cleaning. The submicrometer antimony pentoxide is also more evenly dispersed in the fiber, resulting in better physical properties.

Powdered antimony pentoxide is used primarily in plastics. Stabilizers used to prevent the particles from growing are caustic, and can react with the halogen in the formulation. This can result in color formation and a lower flame-retarding efficiency of the system.

Antimony pentoxide is priced about two to three times higher than the trioxide. However, because it is more efficient than the trioxide, the pentoxide is at least cost-equivalent

Antimony trioxide
Diantimony trioxide

Translated names
antimon-trioxid (hu)
antimona trioksīds (lv)
Antimonitrioksidi (fi)
antimonov trioksid (hr)
antimontrioksid (no)
Antimontrioksiid (et)
antimontrioxid (da)
diantimonov trioksid (sl)
diantimontrioksid (no)
diantimontrioxid (da)
diantimoontrioxide (nl)
oxid antimonitý (cs)
stibio trioksidas (lt)
tlenek antymonawy (pl)
tlenek antymonu(III) (pl)
triossido di diantimonio (it)
trioxide de antimoniu (ro)
trioxyde d'antimoine (fr)
tritlenek antymonu (pl)
trióxido de diantimonio (es)
trióxido de diantimónio (pt)
τριοξείδιο του διαντιμόνιου τριοξείδιο του aντιμονίου (el)
антимонов триоксид (bg)
CAS names
Antimony oxide (Sb2O3)
IUPAC names
(stibanyloxy)stibanediol
anitimony troxide
antimoniy trioxide
Registration dossier
Antimony
Registration dossier
Antimony (III) oxide
Antimony oxide
Antimony Trioxite
antimony trisuphide
C&L Inventory
antimony(3+) oxide
Antimony(III) oxide
diamtimony trioxide
diantimony trioxid
Diantimony trioxide_049
Diantimony trioxide_068
diantimony-trioxide-
Dioxodistiboxane
oxo(oxostibanyloxy)stibane
Oxo(oxostibanyloxy)stibane / antimony(3+); oxygen(2-)
oxostibanyl stibinate
Sb2O3
Trade names
Antimonio triossido
Antimony Trioxide TMS®-HP
ATO
Dust-free antimony trioxide
flame retardant masterbatch
Timonox® Blue Star