Azure B is a synthetic dye belonging to the thiazine class. Chemically, it is a cationic dye, which it carries a positive charge that allows it to interact with negatively charged molecules. It is produced via oxidation from methylene blue, and it’s closely related to other dyes in the azure series. In its solid form, it appears as a greenish-blue powder or crystals.
CAS No.: 531-55-5
Synonyms: Azure I; Methylene azure B; 3-(Dimethylamino)-7-(methylamino)phenothiazin-5-ium chloride; Trimethylthionine chloride; AZUR I; C.I. 52010; N,N,N’-Trimethylthionin; 3-(Dimethylamino) -7- (methylamino)-phenothiazin-5-ium chloride; 3-(Dimethylamino)-7-(methylimino)-3H-phenothiazine hydrochloride
| Physical Properties | |
| Chemical formula | C15H16ClN3S |
| IUPAC Name | dimethyl-[7-(methylamino)phenothiazin-3-ylidene]azanium;chloride |
| Molecular weight | 305.8 g/mol |
| Solubility | Soluble in Water & Ethanol |
| Density |  1.18 g/cm³ |
| Chemical Properties | |
| Colour | Blue to Greenish-blue |
| State | Powder or Crystals |
| Melting point | 200 – 205 °C |
| λmax | 645 nm |
| pKa | 7.4 |
| Pictograms : |  |
| Hazard Statements : | H302: Harmful if swallowed |
| Precautionary statements : | P264: Wash skin thoroughly after handling. |
Azure B is a synthetic dye belonging to the thiazine class. Chemically, it is a cationic dye, which it carries a positive charge that allows it to interact with negatively charged molecules. It is produced via oxidation from methylene blue, and it’s closely related to other dyes in the azure series. In its solid form, it appears as a greenish-blue powder or crystals.
CAS No.: 531-55-5
Synonyms: Azure I; Methylene azure B; 3-(Dimethylamino)-7-(methylamino)phenothiazin-5-ium chloride; Trimethylthionine chloride; AZUR I; C.I. 52010; N,N,N’-Trimethylthionin; 3-(Dimethylamino) -7- (methylamino)-phenothiazin-5-ium chloride; 3-(Dimethylamino)-7-(methylimino)-3H-phenothiazine hydrochloride
| Physical Properties | |
| Chemical formula | C15H16ClN3S |
| IUPAC Name | dimethyl-[7-(methylamino)phenothiazin-3-ylidene]azanium;chloride |
| Molecular weight | 305.8 g/mol |
| Solubility | Soluble in Water & Ethanol |
| Density |  1.18 g/cm³ |
| Chemical Properties | |
| Colour | Blue to Greenish-blue |
| State | Powder or Crystals |
| Melting point | 200 – 205 °C |
| λmax | 645 nm |
| pKa | 7.4 |
| Pictograms : | |
| Hazard Statements : | H302: Harmful if swallowed |
| Precautionary statements : | P264: Wash skin thoroughly after handling. |
Azure B stains cellular components such as nuclei, cytoplasmic granules, and various tissue structures in biological samples.
Azure B is a basic dye used in combination with an acidic dye like esosin in staining.
Azure B and Methylene Blue vary in their chemical structures and staining properties. Azure B is used in Romanowsky stains and it has a blue-green color, while Methylene Blue is a blue dye used in various general staining applications. Their distinct absorption spectra also affect the staining intensity and specificity.
Yes, Azure B is fluorescent. It emits light when exposed to ultraviolet or visible light, which is useful in various staining techniques.
Azure B is generally stable in a neutral to slightly basic pH range, typically around 7 to 9.
