Formula: C₁₅H₁₇ClN₄ (chloride salt) CAS: 553-24-2 EC No.: 209-035-8 M: 288.78 g/mol D: ~1.00 g/cm³ (solution) mp: Not applicable bp: Not applicable Optical Rotation: Not applicable

Concentration: Typically 0.1% w/v in water or ethanol/water. Appearance: Red to reddish-brown solution. pH Transition: Red 6.8 – 8.0 Yellow. Color Change Test: Passes test (red in pH 6.5 buffer, yellow in pH 8.2 buffer). Absorbance Maximum: ~533 nm (red form). Clarity: Clear solution.