Rhodamine 6G

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Rhodamine 6G
Rhodamine 6G (hydrochloride)
Preferred IUPAC name
9-[2-(Ethoxycarbonyl)phenyl]-N-ethyl-6-(ethylamino)-2,7-dimethyl-3H-xanthen-3-iminium chloride
Other names
Rhodamine 590, R6G, Rh6G, C.I. Pigment Red 81, C.I. Pigment Red 169, Basic Rhodamine Yellow , C.I. 45160
ECHA InfoCard 100.012.350 Edit this at Wikidata
EC Number
  • 213-584-9
RTECS number
  • DH0175000
  • InChI=1S/C28H30N2O3.ClH/c1-6-29-23-15-25-21(13-17(23)4)27(19-11-9-10-12-20(19)28(31)32-8-3)22-14-18(5)24(30-7-2)16-26(22)33-25;/h9-16,29H,6-8H2,1-5H3;1H/b30-24-; checkY
Molar mass 479.02 g/mol
Appearance dark reddish purple, brown or black crystalline solid
Density 1.26 g/cm3 [citation needed]
20 g/L (25 °C) [citation needed]
Solubility in methanol 400 g/L [citation needed]
GHS labelling:
GHS05: CorrosiveGHS06: ToxicGHS07: Exclamation markGHS09: Environmental hazard
H301, H302, H318, H410, H411
P264, P270, P273, P280, P301+P310, P301+P312, P305+P351+P338, P310, P321, P330, P391, P405, P501
Safety data sheet (SDS) External MSDS
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Rhodamine 6G /ˈrdəmn/ is a highly fluorescent rhodamine family dye. It is often used as a tracer dye within water to determine the rate and direction of flow and transport. Rhodamine dyes fluoresce and can thus be detected easily and inexpensively with instruments called fluorometers. Rhodamine dyes are used extensively in biotechnology applications such as fluorescence microscopy, flow cytometry, fluorescence correlation spectroscopy and ELISA.


Rhodamine 6G chloride powder mixed with methanol, emitting yellow light under green laser illumination

Rhodamine 6G usually comes in three different forms. Rhodamine 6G chloride is a bronze/red powder with the chemical formula C28H31ClN2O3. Although highly soluble, this formulation is very corrosive to all metals except stainless steel. Other formulations are less soluble, but also less corrosive. Rhodamine 6G perchlorate (C28H31ClN2O7) comes in the form of red crystals, while rhodamine 6G tetrafluoroborate (C28H31BF4N2O3) appears as maroon crystals.[1]


Butanol (40 g/L), ethanol (80 g/L), methanol (400 g/L), propanol (15 g/L), MEG (50 g/L), DEG ( 100 g/L), TEG (100 g/L), isopropanol (15 g/L), ethoxyethanol (25 g/L), methoxyethanol (50 g/L), dipropylene glycol (30 g/L), PEG (20 g/L).[2]

Laser dye[edit]

Rhodamine 6G-based dye laser. The dye solution is the orange fluid in the tubes.

Rhodamine 6G is also used as a laser dye, or gain medium, in dye lasers,[3][4] and is pumped by the second (532 nm) harmonic from an Nd:YAG laser, nitrogen laser, or argon ion laser.[5] The dye has a remarkably high photostability, high fluorescence quantum yield (0.95[6]), low cost, and its lasing range has close proximity to its absorption maximum (approximately 530 nm). The lasing range of the dye is 570 to 660 nm with a maximum at 590 nm.[7]


The refractive index of Rhodamine 6G has been determined in recent studies. According to research published in ACS Applied Materials & Interfaces[8] and the Refractive Index Database,[9] the refractive index is 1.87 (k=0.79) for 532 nm wavelength.

See also[edit]


  1. ^ http://www.exciton.com/pdfs/RH590.pdf [bare URL PDF]
  2. ^ "Rhodamine 6G".
  3. ^ F. P. Schäfer (Ed.), Dye Lasers, 3rd Ed. (Springer-Verlag, Berlin, 1990).
  4. ^ F. J. Duarte and L. W. Hillman (Eds.), Dye Laser Principles (Academic, New York, 1990).
  5. ^ Peterson, O. G.; Tuccio, S. A.; Snavely, B. B. (1970). "cw OPERATION OF AN ORGANIC DYE SOLUTION LASER". Applied Physics Letters. 17 (6): 245–247. doi:10.1063/1.1653384. ISSN 0003-6951.
  6. ^ R. F. Kubin and A. N. Fletcher, "Fluorescence quantum yields of some rhodamine dyes." J. Luminescence 27 (1982) 455
  7. ^ Yarborough, J. M. (1974). "cw dye laser emission spanning the visible spectrum". Applied Physics Letters. 24 (12): 629–630. Bibcode:1974ApPhL..24..629Y. doi:10.1063/1.1655082. ISSN 0003-6951.
  8. ^ Seçkin, S.; Singh, P.; Jaiswal, A.; König, T.A.F. (2023). "Super-radiant SERS enhancement by plasmonic particle gratings". ACS Applied Materials & Interfaces. 15 (36): 43124–43134. doi:10.1021/acsami.3c07532. PMID 37665350. S2CID 261511455.
  9. ^ Refractive Index Database entry for Rhodamine 6G