NEUTRAL RED - (553-24-2)


Name: neutral red; C.I. basic red 5; toluylene red
CAS Number: 553-24-2
Chemical Formula: C15H17ClN4
Molar Mass: 288.77528 g
State of Matter: dark green powder
Mass Percent: C 62.387 %; H 5.9336 %; Cl 12.277 %; N 19.401 % 



• "As indicator (0.1% in 60% alcohol) for alkalinity of water, urea, nitrite, etc. pH: 6.8 red; 8.0 yellow. Also used for preparing neutral-red paper. As biological stain (study of the Golgi apparatus in cells)." 1


insoluble:  1
soluble:  1


Double Bonds: 7
Triple Bonds: 0
Sigma Bonds: 39
Pi Bonds: 7
Total: 46
Carboxyl Groups: 0
Hydroxyl Groups: 0
Hybridization: aromatic carbons and nitrogens are sp2; other carbons and nitrogens are sp3

Safety Information

NFPA 704 Ratings:
Health: 1 - Exposure would cause irritation with only minor residual injury.
Flammability: 1 - Must be heated before ignition can occur. Flash point over 93°C (200°F).
Reactivity: 0 - Normally stable, even under fire exposure conditions, and is not reactive with water.

For More Information


(1) - The Merck Index: An Encyclopedia of Chemicals, Drugs, and Biologicals, 13th ed.; Budavari, S.; O'Neil, M.J.; Smith, A.; Heckelman, P. E.; Kinneary, J. F., Eds.; Merck & Co.: Whitehouse Station, NJ, 2001; entry 6512.