Methylene blue, chemically known as methylthioninium chloride, has the formula C16H18ClN3S and a molecular weight of 319.85 g/mol319.85 space g / m o l319.85 𝑔/𝑚𝑜𝑙. It is a tricyclic phenothiazine dye used medically to treat methemoglobinemia, as a stain in biology, and in various industrial applications like dyeing fabrics. The compound’s blue color comes from its ability to absorb light in the visible spectrum.

Chemical properties

Chemical formula:

C16H18ClN3Scap C sub 16 cap H sub 18 cap C l cap N sub 3 cap S𝐶16𝐻18𝐶𝑙𝑁3𝑆
Molecular weight:

319.85 g/mol319.85 space g / m o l319.85 𝑔/𝑚𝑜𝑙
Chemical name: Methylthioninium chloride
Type: Cationic dye, a tricyclic phenothiazine
Solubility: Soluble in water and some organic solvents
Color: Produces a striking blue color when dissolved in water

Medical uses

Methemoglobinemia:

Methylene blue is a primary treatment for this condition, where it helps convert methemoglobin back to hemoglobin, improving oxygen delivery to tissues.
Antidote:

It can be used as an antidote to cyanide poisoning.
Staining:

Used as a biological stain for easier observation of cells and tissues under a microscope.
Other conditions:

It has also been explored for potential use in photodynamic therapy, managing certain cancers, and treating conditions like Alzheimer’s and oral mucositis.