Halochromism

Halochromism " salt color " means the color change chemistry of a substance in response to the charge state of its molecule.

Halo Chrome show color shifts with variation of the state of charge (for example, in the salt formation ). This important phenomenon in the chemistry of dyes can be observed (for example, phenolphthalein or litmus ) at different acid -base indicators. As a weak organic acid phenolphthalein is in the weakly acidic to neutral medium uncharged and colorless. In alkaline solutions, the indicator molecule is due to a negative charge, a red color. Litmus changes depending on the pH value of an aqueous solution its color from red ( acidic) to blue ( basic).

• Spectroscopy
• Colors