An Introduction of the indigo blue
Indigo Blue:coloring matler index C.1 revert blue (73000)
Strutural formula:
 


Molecular formula: C₁₆H₁₀N₂O₂

Relative molecular weight:262.27(according to the International molecular weight of 1983)
Nature:the appearance is dark blue even grains.It dissolves in hot anilin,but not in water.It turns yellow green when meeting the oil of vitriol.It is yellow in alkaline rongalite revert liquid and white in acidic liquid.
Use:It is mainly used to dye cotton fibre .The pop "cowboy" clothes mostly are made by indigo blue dying longitudinal yarn and white yarn interweaving;It can be used with sulfurated coloring matter;Also we can get indigo white,bromized indigo blue from it,they are well used in food coloring matter,biochemistry etc.