Precipitate
An insoluble solid that separates from a solution as the result of a chemical reaction.
Unit
g
In depth
A precipitate forms once the ionic product exceeds the solubility product, and its colour, texture and solubility in excess reagent are diagnostic in qualitative analysis. Slow precipitation from hot dilute solution gives large, easily filtered crystals rather than a colloidal, hard-to-filter mass.
Examples in the real world
White AgCl darkening in light, yellow PbCrO₄, and the gelatinous rust-brown Fe(OH)₃.