dispersion, in chemistry, mixture in which fine particles of one substance are scattered throughout another substance. A dispersion is classed as a suspension, colloid, or solution. Generally, the particles in a solution are of molecular or ionic size; those in a colloid are larger but too small to be observed with an ordinary microscope; those in a suspension can be observed under a microscope or with the naked eye. A coarse mixture (e.g., sand mixed with sugar) is usually not thought of as a dispersion.
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