A white powder that can occur in three crystalline forms: calcite (hexagonal-rhombohedral), aragonite (orthorhombic) and vaterite. Calcium carbonate occurs naturally in many forms such as chalk, limestone, marble and sea shells. It can be found worldwide and ranges in color (because of impurities) from white to gray to yellow. A white pigment of calcium carbonate is prepared by grinding limestone, chalk or shells with water then using levigation to separate the coarser material. Artificial chalk, also known as precipitated chalk, is whiter and more homogeneous than natural chalk. Pearl white is made from calcined oyster shells.
Synonyms and Related Terms
chalk; carbonate de calcium (Fr.); Kalziumkarbonat (Deut.); carbonato cálcico (Esp.); carbonato de calcio (Esp.); calciumcarbonaat (Ned.); gofun (Jap.); aragonite; pearl white; oystershell white; shell white; marble; limestone, whiting; lime white; marl; travertine; Pigment White 18; white earth; English white; Paris white; drop chalk
Particle size = 0.1-10 micrometers. Insoluble in water. May fluoresce a medium purple color in ultraviolet light. Reacts with acids to evolve carbon dioxide.
|Molecular Weight||mol. wt. = 100.09|
|Refractive Index||1.510; 1.645|
Hazards and Safety
No significant hazards.
Mallinckrodt Baker: MSDS
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