7758-97-6 Usage
Description
Lead chromate, also known as chrome yellow, is a chemical compound with the formula PbCrO4. It is a yellow monoclinic crystal with a refractive index of 2.31, a density of 6.12 g/cm3, and melts at 844°C. It is insoluble in water, ammonia, and acetic acid but soluble in acids and alkalies. Lead chromate is found in nature as yellow crystals in the mineral crocoite and can be produced by reacting lead chloride and sodium dichromate.
Uses
1. Chemical Analysis Industry:
Lead chromate is used as a reagent in the chemical analysis of organic substances.
2. Paint and Ink Industry:
Lead chromate is used as a pigment in the production of commercial lead chromate pigments, such as Primrose Chrome Yellow, Light Chrome Yellow, and Medium Chrome Yellow, which contain 65-89% lead chromate.
3. Oil and Water Colors Industry:
Lead chromate is used as a pigment in oil paints and water colors due to its bright yellow color and insolubility in water.
4. Textile Industry:
Lead chromate is used for printing textiles, providing a vibrant and long-lasting color.
5. Porcelain and Ceramic Industry:
Lead chromate is used for decorating china and porcelain, adding a rich yellow hue to the final product.
6. Green Pigment Industry:
Lead chromate (VI) is used in the preparation of green pigments such as chrome green or green cinnabar, in which it is mixed with Prussian blue.
7. Traffic Paint Industry:
Lead chromate is used in traffic paints for its bright color and durability.
History
Lead chromate(VI), PbCrO4, also known as plumbous chromate, was first synthesised around 1800, with its potential use as a pigment first reported by Berthollet and Vauquelin in 1804. According to Vauquelin (1809), it was prepared by adding lead acetate or lead nitrate to potassium chromate, and the shade of the precipitate could be varied (from yellow to orange or red) by adjusting the acidity/alkalinity of the products. Lead chromate( VI), which occurs naturally as the rare mineral crocoite (Rutley, 1988), is known as the pigment chrome yellow (qq.v.). It is listed by the Colour Index (1971) as CI Pigment Yellow 34 (CI 77600). The commercial manufacture of the pigment was largely influenced by the availability of suitable raw materials (usually in the form of the abundant mineral chromite, FeCr2O4). The earliest record of the use of chrome yellow is in a painting by Sir Thomas Lawrence dated prior to 1810 (Kühn, 1969). Sources of the pigment are reported by Harley (1982, citing Field, 1809) to be available by 1814-15, with Bollman (1769-1821) cited as the first commercial manufacturer in England, with production beginning around 1814-16.
Production
Lead chromate is found naturally in minerals crocoite and phoenicochroite. It also is readily prepared by adding a soluble chromate such as sodium or potassium chromate to a solution of lead nitrate, lead acetate or other soluble lead(II) salt in neutral or slightly acidic solution:
Pb2+ + CrO42ˉ → PbCrO4
The yellow precipitate is filtered, washed and dried.
Toxicity
Moderately toxic by intraperitoneal route. The effects, however, are mild from oral intake. Occupational exposure may cause cancer. There is sufficient evidence of carcinogenicity in animals and humans.
Health Hazard
Lead chromate is a suspected
human lung carcinogen and can cause chronic
lead poisoning.
Check Digit Verification of cas no
The CAS Registry Mumber 7758-97-6 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 7,7,5 and 8 respectively; the second part has 2 digits, 9 and 7 respectively.
Calculate Digit Verification of CAS Registry Number 7758-97:
(6*7)+(5*7)+(4*5)+(3*8)+(2*9)+(1*7)=146
146 % 10 = 6
So 7758-97-6 is a valid CAS Registry Number.
InChI:InChI=1/Cr.4O.Pb.4H/q;;;2*-1;+2;;;;/rCrO4.H4Pb/c2-1(3,4)5;/h;1H4/q-2;+2
