Physical state at 20 °C | Solid | Colour | Orange powder |
Melting point/ Freezing point [°C] | 279 – 283 °C | Solubility in water [% weight] | Sparingly soluble in water |
pH value | 5-7.2 | Boiling point [°C] | 430°C |
Appearance | Orange colored powder |
pH 5.5- 6.8 | Yellow to reddish-violet |
Absorption maxima in NaOH 0.01 mol/L (lmax1) | 564 – 568 nm |
Absorption maxima in NaOH 0.01 mol/L (lmax2) | 605 – 609 nm |
Absorptivity (A 1%/1cm; at lmax2) | Min 525 |
Sulphated ash | Max 1% |
Loss on drying | Max 5% |
Absorptivity (A 1%/1cm; at lmax1) | Min 625 |