What is the difference between Rhodamine B and Rhodamine 6G?

Rhodamine B is a bright red fluorescent xanthene dye. Its chemical formula is C₂₈H₃₁ClN₂O₃. It is soluble in water and methanol, and has an excitation/ emission maxima of 568/583 nm. Rhodamine functions as a water tracer fluorescent and is used extensively as a staining fluorescent dye.

Rhodamine 6G is a dark reddish purple organic laser dye. Its chemical formula is C₂₈H₃₁N₂O₃Cl. It is soluble in water and methanol and has an excitation/emission maxima of 525/548 nm. Rhodamine 6G has a high quantum yield for fluorescence to study probes and can be used as a fluorescence tracker.