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32745 Sigma-Aldrich

Malachite Green oxalate salt

for microscopy, crystalline, S. No.: 754

Synonym: N,N,N′,N′-Tetramethyl-4,4′-diaminotriphenylcarbenium oxalate, Basic Green 4

  • CAS Number 2437-29-8

  • Empirical Formula (Hill Notation) C23H25N2 · C2HO4 · 0.5C2H2O4

  • Molecular Weight 463.50

  •  Colour Index Number 42000

  •  Beilstein/REAXYS Number 3644550

  •  EC Number 219-441-7

  •  PubChem Substance ID 57648708

  •  NACRES MA.02



Related Categories Analytical Reagents, Analytical/Chromatography, Base Ingredients for Media, Indicators, Microbiology,
Quality Level   200
grade   for microscopy
form   crystalline
application(s)   hematology: suitable
  histology: suitable
color   S. No.: 754
mp   144-150 °C
solubility   methanol: 0.01 g/10 mL, blue to very deep blue
εmax   ≥1650 at 609-619 nm in water
  ≥300 at 420-430 nm in water
Featured Industry   Diagnostic Assay Manufacturing
storage temp.   room temp
SMILES string   C[N+](C)=C1C=CC(C=C1)=C(C2=CC=C(N(C)C)C=C2)C3=CC=CC=C3.[O-]C(C(O)=O)=O
InChI   1S/C23H25N2.C2H2O4/c1-24(2)21-14-10-19(11-15-21)23(18-8-6-5-7-9-18)20-12-16-22(17-13-20)25(3)4;3-1(4)2(5)6/h5-17H,1-4H3;(H,3,4)(H,5,6)/q+1;/p-1


General description

Malachite green is manufactured as a zinc-free oxalate salt (green crystals with a metallic sheen) or as a zinc chloride salt (yellow crystals). Malachite green comes under the triphenyl methane class of dyes and is one of the most effective agents traditionally known for treating water mold infections of fish and eggs. It has also been found to be effective against ectoparasites, protozoan and some myxozoan parasites. Though it has several disadvantages like it acts as respiratory poison, teratogen and suspected carcinogen. It generated free radicals, thereby making it highly toxic to mammalian cells in culture; it also causes malignant transformation. It has a long half-life and can persist in tissues for long periods. In water, malachite green exists in equilibrium between the colored, ionic form and the colorless, nonionic pseudobase (carbinol form). Only the colored ionic form has antimicrobial activity, whereas the carbinol form is lipid-soluble, hence allowing it to pass across membranes. The toxicity of malachite green is dependent on temperature and it increase with increase in temperature, whereas it is more toxic at low pH and low hardness. It is phyotoxic in nature, thereby it is inactivated (oxidised) by light.


Malachite green oxalate salt was used in studying the photocatalytic degradation with TiO2/WO3. It was also used in preparing selective medium for isolating Verticillium fungicola from mushroom. It may be used for the determination of phosphate in serum. It may also be used to monitor the presence of free COOH on the solid-phase. It may be used as reference materials for in an analytical method to independently quantify malachite green oxalate and leucomalachite green in fish tissue. It may also be used in Rappaport broth for incubating the membrane filters used in detecting Salmonella sp.

Safety & Documentation

Safety Information

Signal word 
Hazard statements 
Personal Protective Equipment 
UN2811 - class 6.1 - PG 3 - EHS - Toxic solids, organic, n.o.s., HI: all
WGK Germany 
Flash Point(F) 
Not applicable
Flash Point(C) 
Not applicable


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Protocols & Articles


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