Chemical Properties
Bright yellow monoclinic crystalline system. Density 6.12g/cm3, melting point 844℃. Insoluble in water, oil and acetic acid, soluble in strong alkali and inorganic strong acid. It turns black when it meets hydrogen sulfide and orange-red when it meets alkali. Strong coloring power and covering power. Cannot be shared with Lidl and Ultramarine. Toxic. The color varies with the ratio of raw materials and preparation conditions, and there are five kinds of orange chrome yellow, deep chrome yellow, medium chrome yellow, light chrome yellow and lemon yellow. Lemon Chrome Yellow [3PbCrO4-2PbSO4+Al(OH)3+AlPO4]. The content of lead chromate is not less than 50%, the color is bright, with green phase, the gloss of the paint is good, and the blue pigment can be matched into bright emerald green, the color is equivalent to 10G. the light resistance reaches 4~5 grade. Heat resistance is 140℃. Water permeability and oil permeability are grade 1. Acid resistance and alkali resistance are grade 3. Light chrome yellow (5PbCrO4-2PSO4+Al(OH)3+AlPO4]. The content of lead chromate is not less than 60%, with bright color, strong coloring power, good gloss of paint, and can be matched with blue pigment to form light green. The content of lead chromate is higher than lemon chrome yellow. The color is equivalent to 4G, and the light resistance is up to grade 5. Heat resistance is 140℃. Water permeability and oil permeability are grade 1. Acid resistance and alkali resistance are grade 3. Medium chrome yellow (PbCrO4+PbSO4). Pure color, good gloss of paint, can be matched with blue pigment to form medium green. The content of lead chromate is the highest, above 90%. The color is equivalent to G. The light resistance is 4~5 grade. Heat resistance is 140℃. Water permeability and oil permeability are grade 1. Acid resistance, alkali resistance is grade 3. Deep chrome yellow (PbCrO4+PbCrO4-PbO). Lead chromate 85%, with reddish tint, strong coloring power, color equivalent to GR. Light resistance is grade 5. Heat resistance is 140℃. Water permeability and oil permeability are grade 3. Orange chrome yellow (PbCrO4-PbO). It is alkaline lead chromate with PbCrO4 content not less than 55% and orange color. The light resistance is good, up to 5~grade. Heat resistance is 150℃. Water permeability and oil permeability are grade 1. Acid resistance, alkali resistance is 3 levels.
Definition
ChEBI: Lead chromate is a chromium coordination entity comprising chromate and lead(2+) ions in a 1:1 ratio It has a role as a carcinogenic agent, a neurotoxin and a nephrotoxin. It is a lead coordination entity and a chromium coordination entity. It contains a lead(2+) and a chromate(2-).
