1-nitroso-3,6-disulfonate

You're likely referring to **1-nitroso-2-naphthol-3,6-disulfonate** (also known as **Nitroso-R-salt**). This compound is a **dye** and **reagent** with several applications in research.

**Structure and Properties:**

* It's a sulfonated derivative of 1-nitroso-2-naphthol.
* It's a **bright orange-red solid** that dissolves in water to give a **yellow-brown solution**.
* The sulfonate groups (-SO3-) increase its water solubility.

**Importance in Research:**

**1. Colorimetric Analysis:**

* Nitroso-R-salt is used as a **colorimetric reagent** for determining the concentration of various metal ions, including **cobalt**, **nickel**, and **palladium**.
* Its reaction with these metals forms colored complexes with distinct absorption maxima, enabling quantitative analysis.

**2. Dye Chemistry:**

* It's a **reactive dye** used in the textile industry to color fabrics.
* Its azo coupling reactions with aromatic amines create various dyes with distinct color shades.

**3. Analytical Chemistry:**

* It's employed in **spectrophotometry** for determining the concentration of certain analytes based on color changes.

**4. Other Applications:**

* **Chelating agent:** It can bind to metal ions, acting as a chelating agent in various chemical reactions.
* **Corrosion inhibitor:** Its ability to form complexes with metal ions can inhibit corrosion in certain applications.

**Note:** The term 1-nitroso-3,6-disulfonate is technically incorrect, as it refers to the specific functional groups and their positions. The correct and more widely recognized term is **1-nitroso-2-naphthol-3,6-disulfonate** or **Nitroso-R-salt**.