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EC / List no.: 215-160-9
CAS no.: 1308-38-9
Chromium oxide green is among the ten most abundant compounds in the Earth's crust. Chromium oxide green is one of four oxides of chromium, chemical formula Cr2O3.
Chromium oxide green is commonly called "chrome green" when used as a pigment; however it was referred to as “viridian” when it was first discovered.
Chromium oxide green is a very refractory ceramic colorant (even a 50% mix with a high borax frit will not even begin to melt it in a crucible).
Chrome oxide is the only stable oxide of the metal chromium.
Chromium oxide green is a bright to dark green crystalline powder insoluble in alkalis and acids.
Chromium oxide green is manufactured from the mineral Chromite mined in southern Africa, Asia, Turkey and Cuba.
As with other powerful coloring agents, chrome must be milled fine enough to eliminate specking in glass or glaze.
Chromium is a "fast" colorant, meaning can produce strong green colors under all furnace conditions, slow or fast, reducing or oxidizing.
Chromium oxide green is also a flat colorant (due to its refractory nature), it usually produces an army helmet opaque green.
Chromium oxide green is powerful, typically only 2% will produce a dark color.
Chromium oxide green cannot be used to make a metallic glaze.
Chrome oxide is usually employed in raw glazes whereas potassium dichromate is used in fritted glazes.
Chemical Properties
Chromium oxide is a bright green, odorless powder.
Chromium oxide green pigments are thermally stable and insoluble in water.
Chromium oxide pigments, also called chromium oxide green pigments, consist of chromium(III) oxide [1308-38-9], Cr2O3,Mr 151.99. Chromium oxide green is one of the few single-component pigments with green coloration.
Chrome green is a blend of chrome yellow and iron blue pigments; phthalochrome green is a blend of chrome yellow and blue phthalocyanine pigments.
Alkali dichromates are used as starting materials for the production of chromium(III) oxide pigments.
They are not classified as hazardous materials and are not subject to international transport regulations.
As long as they are kept dry their utility as a pigment is practically unlimited.
Physical properties
Green hexagonal crystal system
orundum type structure
density 5.22 g/cm3
melts at 2,330°C
vaporizes above 3,000°C
insoluble in water and alcohol.
Uses:
Chromium oxide (Cr2O3) is a dull green synthetic inorganic pigment, which can be used in all types of paint systems where high chemical resistance and outstanding light-fastness are required.
In abrasives, refractory materials, electric semiconductors; as pigment, particularly in coloring glass; in alloys; printing fabrics and banknotes; as catalyst for organic and inorganic reactions.
Chromium oxide green is used as pigment for coloring green on glass and fabrics.
Other important applications are in metallurgy; as a component of refractory bricks, abrasives and ceramics; and as a catalyst in hydrogenation, hydrogenolysis and many other organic conversion reactions.
Chromium oxide green also is used to prepare other chromium salts.
Mainly used in special steel smelting tapping mouth, slide mouth and large incinerator
can be used for ceramic and enamel coloring, rubber coloring, preparation of high temperature resistant coatings, art pigments, ink for the preparation of printed notes and securities.
The color of chromium oxide green is similar to that of plant chlorophyll, which can be used in camouflage paint and can be difficult to distinguish in infrared photography.
Also a large number of used in metallurgy, production of refractory materials, grinding powder.
Chromium oxide green can also be used as a catalyst for organic synthesis and is a high-grade green pigment.
Chromium oxide green is used as a spectral analysis reagent, organic synthesis catalyst, ceramic glaze color raw material, and the manufacture of chromium alloy and chromium salt.
Preparation
Chromium oxide green can be obtained by thermal decomposition of ammonium dichromate.
Above ca. 200 °C, a highly voluminous product is formed with elimination of nitrogen.
The pigment is obtained after addition of alkali salts (e.g., sodium sulfate) and subsequent calcination.
In the industrial process, a mixture of ammonium sulfate or chloride and sodium dichromate is calcined:
Na2Cr2O7.2 H2O + (NH4)2SO4 →Cr2O3 + Na2SO4 + 6 H2O + N2
Definition
Chromium oxide (Cr2O3) is a dull yellowish-green pigment that may be prepared by blending an alkali dichromate with sulfur or with a carbonaceous material. Reduction to chrome (III) oxide is achieved in a kiln at 1000°C.
A green crystallinewater-insoluble salt, Cr2O3; r.d. 5.21;m.p. 2435°C; b.p. 4000°C.
Chromium oxide green is obtainedby heating chromium in astream of oxygen or by heating ammoniumdichromate.
The industrialpreparation is by reduction ofsodium dichromate with carbon.
Chromium oxide green is amphoteric,dissolving in acids to give chromium(III) ions and in concentratedsolutions of alkalis to give chromites.
Chromium oxide green is used as a green pigment in glass,porcelain, and oil paint.
Reactions
Chromium oxide green is amphoteric.
Although insoluble in water, it dissolves in acid to produce hydrated chromium ion, [Cr(H2O)6]3+.
Chromium oxide green dissolves in concentrated alkali to yield chromite ion.
When heated with finely divided aluminum or carbon it is reduced to chromium metal:
Cr2O3 + 3Al2Cr + Al2O3
Heating with chlorine and carbon yields chromium(III) chloride:
Cr2O3 + 3Cl2 + 3C2CrCl3 + 3CO
If chromium(III) oxide (also known as chrome green) is heated with potassium carbonate and potassium nitrate, the mixture slowly turns yellow.
This colour change stems from the formation of potassium chromate, K2CrO4, in which chromium is found in oxidation state vi.
General Description
Chromium (III) oxide is a chromium complex in which the chromium ion is in +3 oxidation state.
Structure and properties
Cr2O3 has the corundum structure, consisting of a hexagonal close packed array of oxide anions with 2⁄3 of the octahedral holes occupied by chromium.
Similar to corundum, Cr2O3 is a hard, brittle material (Mohs hardness 8 to 8.5).
Chromium oxide green is antiferromagnetic up to 307 K, the Néel temperature.
Chromium oxide green is not readily attacked by acids.
Occurrence
Cr2O3 occurs naturally as the mineral eskolaite, which is found in chromium-rich tremolite skarns, metaquartzites, and chlorite veins. Eskolaite is also a rare component of chondrite meteorites.
The mineral is named after Finnish geologist Pentti Eskola.
Production
The Parisians Pannetier and Binet first prepared the transparent hydrated form of Cr2O3 in 1838 via a secret process, sold as a pigment.
Chromium oxide green is derived from the mineral chromite, (Fe,Mg)Cr2O4.
The conversion of chromite to chromia proceeds via Na2Cr2O7, which is reduced with sulfur at high temperatures:
Na2Cr2O7 + S → Na2SO4 + Cr2O3
The oxide is also formed by the decomposition of chromium salts such as chromium nitrate, or by the exothermic decomposition of ammonium dichromate.
(NH4)2Cr2O7 → Cr2O3 + N2 + 4 H2O
The reaction has a low ignition temperature of less than 200 °C and is frequently used in “volcano” demonstrations.
Uses
Because of its considerable stability, chromia is a commonly used pigment.
Chromium oxide green was originally called viridian.
Chromium oxide green is used in paints, inks, and glasses.
Chromium oxide green is the colorant in "chrome green" and "institutional green."
Chromium oxide green is a precursor to the magnetic pigment chromium dioxide, by the following reaction:
Cr2O3 + 3 CrO3 → 5 CrO2 + O2
Along with many other oxides, it is used as a compound when polishing (also called stropping) the edges of knives, razors, surfaces of optical devices etc. on a piece of leather, balsa, cloth or other material.
Chromium oxide green is available in powder or wax form, and in this context it is known as "green compound".
Chromium oxide green is used as a component of refractories due to its high melting point.
Reactions
Chromium oxide green is amphoteric. Although insoluble in water, it reacts with acid to produce salts of hydrated chromium ions such as [Cr(H2O)6]3+.
Chromium oxide green is also attacked by concentrated alkali to yield salts of [Cr(OH)6]3−.
When heated with finely divided carbon or aluminium, it is reduced to chromium metal:
Cr2O3 + 2 Al → 2 Cr + Al2O3
Unlike the classic thermite reaction involving iron oxides, the chromium oxide thermite creates few or no sparks, smoke or sound, but glows brightly.
Because of the very high melting point of chromium, chromium thermite casting is impractical.
Heating with chlorine and carbon yields chromium(III) chloride and carbon monoxide:
Cr2O3 + 3 Cl2 + 3 C → 2 CrCl3 + 3 CO
Chromates can be formed by the oxidation of chromium(III) oxide and another oxide in a basic environment:
2 Cr2O3 + 4 MO + 3 O2 → 4 MCrO4
Industry Uses
• Catalyst
• Imported material formed into refractory
• Intermediates
• Lubricants and lubricant additives
• Oxidizing/reducing agents
• PAINT
• Pigments
• Plating agents and surface treating agents
• Process regulators
• Processing aids, not otherwise listed
• Refractories
• Smelter feedstock production
• other industrial function
Consumer Uses
• Adhesives and sealants
• Building/construction materials not covered elsewhere
• Catalyst
• Food packaging
• Fuels and related products
• High temperature refractories for furnace linings.
• Ink, toner, and colorant products
• Metal Reclamation
• Metal products not covered elsewhere
• Misc. glass products
• Paints and coatings
• Paper products
• Plastic and rubber products not covered elsewhere
• Toys, playground, and sporting equipment
General Manufacturing Information
Industry Processing Sectors
• All other basic inorganic chemical manufacturing
• All other basic organic chemical manufacturing
• All other chemical product and preparation manufacturing
• Asphalt paving, roofing, and coating materials manufacturing
• Construction
• Custom compounding of purchased resin
• Fabricated metal product manufacturing
• Industrial gas manufacturing
• Miscellaneous manufacturing
• Nonmetallic mineral product manufacturing (includes clay, glass, cement, concrete, lime, gypsum, and other nonmetallic mineral product manufacturing.
• Paint and coating manufacturing
• Paper manufacturing
• Petrochemical manufacturing
• Petroleum refineries
• Pharmaceutical and medicine manufacturing
• Plastic material and resin manufacturing
• Plastics product manufacturing
• Printing ink manufacturing
• Rubber product manufacturing
• Services
• Soap, cleaning compound, and toilet preparation manufacturing
• Synthetic dye and pigment manufacturing
• Transportation equipment manufacturing
• Wholesale and retail trade
Physical and Chemical Properties
Hexagonal or amorphous dark green powder.
Metallic luster.
cubic or amorphous green powder.
There are usually two shades: light olive green and dark olive green.
Metal color.
The relative density was 5.21.
Melting point 2266 °c.
Boiling point 4000 °c.
Chromium oxide green has excellent heat resistance, can resist temperature of 1000 ° C.
Without discoloration, and is also excellent in acid resistance and alkali resistance.
Insoluble in water, insoluble in acid, soluble in hot alkali metal bromate solution.
Chromium oxide green is extremely stable to light, atmosphere, sulfur dioxide, hydrogen sulfide and other corrosive gases.
Chromium oxide green has a high hiding power, but the tinting power is not better than that of Phthalocyanine Green, the color tone is not bright enough, the particle size is hard, and the paint gloss is slightly poor.
light to dark green fine six-square crystal or powder.
Insoluble in water, ethanol, acetone, slightly soluble in acid, alkali and hot potassium bromate solution.
Preparation Method
Chromium oxide green is prepared by mixing potassium dichromate with sulfur or ammonium chloride and reducing roasting.
Chromium oxide green can also be prepared by heating and decomposing chromic anhydride or ammonium dichromate or chromium hydroxide.
Chromium oxide green is a heat stable chrome oxide green pigment.
The product is used extensively in the coloration of construction materials. In addition, the pigment can also be used for the coloration of glazes, enamels or engobes in the ceramic industry.
The product exhibits good dispersibility, even in processes which have short dwell times and relatively low shear forces.
Chromium oxide green is easy to break down and distribute to reach its final tinting strength quickly.
Chromium oxide green is very lightfast and weather stable.
Product Applications
• Asphalt
• Concrete Masonry Blocks
• Concrete Roofing Tiles
• Construction material
• Enamel
• Engobes
• Fibre Cement
• Glazes
• Mortar
• Plaster
• Roofing Felts
• Sand-lime Bricks
• Screed
About Chromium oxide green
Helpful information
Chromium oxide green is registered under the REACH Regulation and is manufactured in and / or imported to the European Economic Area, at ≥ 10 000 tonnes per annum.
Chromium oxide green is used by consumers, in articles, by professional workers (widespread uses), in formulation or re-packing, at industrial sites and in manufacturing.
Consumer Uses
Chromium oxide green is used in the following products: coating products, fillers, putties, plasters, modelling clay, cosmetics and personal care products, finger paints and adhesives and sealants.
Other release to the environment of Chromium oxide green is likely to occur from: outdoor use, indoor use (e.g. machine wash liquids/detergents, automotive care products, paints and coating or adhesives, fragrances and air fresheners), indoor use in close systems with minimal release (e.g. cooling liquids in refrigerators, oil-based electric heaters) and outdoor use in close systems with minimal release (e.g. hydraulic liquids in automotive suspension, lubricants in motor oil and break fluids).
Article service life
Release to the environment of Chromium oxide green can occur from industrial use: industrial abrasion processing with low release rate (e.g. cutting of textile, cutting, machining or grinding of metal).
Other release to the environment of Chromium oxide green is likely to occur from: indoor use in long-life materials with low release rate (e.g. flooring, furniture, toys, construction materials, curtains, foot-wear, leather products, paper and cardboard products, electronic equipment), outdoor use in long-life materials with low release rate (e.g. metal, wooden and plastic construction and building materials) and outdoor use in long-life materials with high release rate (e.g. tyres, treated wooden products, treated textile and fabric, brake pads in trucks or cars, sanding of buildings (bridges, facades) or vehicles (ships)).
Chromium oxide green can be found in complex articles, with no release intended: vehicles, machinery, mechanical appliances and electrical/electronic products (e.g. computers, cameras, lamps, refrigerators, washing machines) and electrical batteries and accumulators.
Chromium oxide green can be found in products with material based on: stone, plaster, cement, glass or ceramic (e.g. dishes, pots/pans, food storage containers, construction and isolation material), plastic (e.g. food packaging and storage, toys, mobile phones) and metal (e.g. cutlery, pots, toys, jewellery).
Widespread uses by professional workers
Chromium oxide green is used in the following products: coating products, cosmetics and personal care products, fillers, putties, plasters, modelling clay, finger paints, laboratory chemicals and pH regulators and water treatment products.
Chromium oxide green is used in the following areas: building & construction work and formulation of mixtures and/or re-packaging.
Chromium oxide green is used for the manufacture of: mineral products (e.g. plasters, cement), plastic products and chemicals.
Other release to the environment of Chromium oxide green is likely to occur from: indoor use (e.g. machine wash liquids/detergents, automotive care products, paints and coating or adhesives, fragrances and air fresheners), outdoor use, indoor use in close systems with minimal release (e.g. cooling liquids in refrigerators, oil-based electric heaters) and outdoor use in close systems with minimal release (e.g. hydraulic liquids in automotive suspension, lubricants in motor oil and break fluids).
Formulation or re-packing
Chromium oxide green is used in the following products: coating products, fillers, putties, plasters, modelling clay, cosmetics and personal care products, finger paints, pH regulators and water treatment products, inks and toners, non-metal-surface treatment products, metals and metal surface treatment products.
Release to the environment of Chromium oxide green can occur from industrial use: formulation of mixtures and formulation in materials.
Uses at industrial sites
Chromium oxide green is used in the following products: coating products, cosmetics and personal care products, fillers, putties, plasters, modelling clay, metals, pH regulators and water treatment products, finger paints, non-metal-surface treatment products and metal surface treatment products.
Chromium oxide green is used in the following areas: formulation of mixtures and/or re-packaging.
Chromium oxide green is used for the manufacture of: chemicals, plastic products, mineral products (e.g. plasters, cement), metals, fabricated metal products and machinery and vehicles.
Release to the environment of Chromium oxide green can occur from industrial use: in the production of articles, of substances in closed systems with minimal release, as an intermediate step in further manufacturing of another substance (use of intermediates), as processing aid and in processing aids at industrial sites.
Manufacture
Release to the environment of Chromium oxide green can occur from industrial use: manufacturing of the substance.
IUPAC NAMES:
C.I. Pigment Green 17
Chrom(III)-oxid
Chrome sesquioxide
Chromic oxide
chromic oxide
Chromic oxide
CHROMIUM (III) OXIDE
Chromium (III) Oxide
Chromium (III) oxide
chromium (III) oxide
chromium (iii) oxide
Chromium (III) Oxide
Chromium (III) oxide
chromium (III) oxide
chromium (III) oxide dihydrate
Chromium (III) oxide dihydrate
chromium (III) oxide; chromic oxide
Chromium (lll) oxide
Chromium III Oxide
CHROMIUM OXIDE
Chromium Oxide
Chromium oxide
chromium oxide
Chromium oxide
CHROMIUM OXIDE (CR2O3)
Chromium oxide (Cr2O3)
CHROMIUM OXIDE GREENS
Chromium oxide green
chromium(III) oxide
Chromium oxide green
Chromium(III) sesquioxide
Chromium(III)Oxide
Chromium(III)oxide
chromium(III)oxide
Chromium(III)oxide
Cr2O3
Dichrome trioxide
dichromium trioxid
Dichromium trioxide
dichromium trioxide
dichromium trioxide
dichromium(3+) trioxidandiide
Hydrated Chromium Oxide
mium (III) oxide
oxo(oxochromiooxy)chromium
oxo-(oxochromiooxy)chromium
oxo[(oxochromio)oxy]chromium
Tlenek chromu III
trioxochromium
SYNONYMS:
Chromium(III) oxide
1308-38-9
Dichromium trioxide
Chromia
Chromium sesquioxide
CHROMIC OXIDE
Chrome oxide
Chrome Green
Chromium Oxide Pigment
oxo(oxochromiooxy)chromium
Chromium oxide (Cr2O3)
Green chromium oxide
Chromic oxide pigment
Chromium(3+) oxide
Green oxide of chromium
Chromium(III) sesquioxide
MFCD00010949
196696-68-1
Green cinnabar
Chrome ochre
Green rouge
Anadonis Green
Casalis Green
Leaf green
Chrome Ocher
Levanox green ga
Oxide of chromium
Green chrome oxide
Chromic Acid Green
Green chromic oxide
C-Grun [German]
Chrome Green F 3
Kromex U 1
Chromium Oxide Green
Chromium oxide greens
OKhP1
OIL GREEN
Chrome Oxide Green BX
Chrome Oxide Green GP
Amperit 704.0
Chromium(3+) trioxide
CI Pigment Green 17
Amdry 6410
Chromium Oxide X1134
Chrome Oxide Green GN-M
11661 Green
C.I. Pigment Green 17
Dichromium trioxide [BAN]
Chromium oxide (Cr8O12)
C-Grun
Chrom(III)-oxid
Pigment green 17
Pure chromium oxide green 59
CCRIS 3182
Chromium(III) oxide (2:3)
Green oxide of chromium oc-31
HSDB 1619
Cosmetic hydrophobic Green 9409
Chrome oxide (Cr2O3)
EINECS 215-160-9
PK 5304
Cosmetic micro blend chrome oxide 9229
CI 77288
P 106F10
C.I. 77288
Chromic Sesquioxide
chromium;trioxochromium
DSSTox_CID_326
CHROMIUM(III)OXIDE
EC 215-160-9
Chromic oxide [Chromium and chromium compounds]
DSSTox_RID_75514
DSSTox_GSID_20326
Chromium(III) oxide, ultra dry
DTXSID4043721
CHEBI:48242
Chromium Oxide Powder, 99% Nano
Chromium(III) oxide, Puratronic?
Tox21_200784
AKOS015904053
Chromium(III) oxide, puriss., 98%
Chromium(III) oxide, powder, >=98%
NCGC00248833-01
NCGC00258338-01
FT-0694904
Chromium(III) oxide, SAJ first grade, >=99.0%
Q407905
Chromium(III) oxide, fused, pieces, 3-6 mm, >=99%
Chromium(III) oxide, powder, 99.9% trace metals basis
Chromium(III) oxide sputtering target, 50.8mm (2.0in) dia x 3.18mm (0.125in) thick
Chromium(III) oxide sputtering target, 76.2mm (3.0in) dia x 3.18mm (0.125in) thick
Chromium(III) oxide sputtering target, 76.2mm (3.0in) dia x 6.35mm (0.250in) thick
Chromium(III) oxide, nanopowder, <100 nm particle size (TEM), 98% trace metals basis
