| Bromocresol purple | |
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4,4'-(1,1-Dioxido-3H-2,1-benzoxathiole-3,3-diyl)- bis(2-bromo-6-methylphenol) |
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Other names
5',5''-Dibromo-o-cresolsulfonephthalein |
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| Identifiers | |
| CAS number | 115-40-2 |
| PubChem | 8273 |
| ChemSpider | 7974 |
| Jmol-3D images | Image 1 |
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| Properties | |
| Molecular formula | C21H16Br2O5S |
| Molar mass | 540.22 g mol−1 |
| Appearance | Purple powder |
| Melting point |
241 - 242 °C (decomposition) |
| Solubility in water | < 0.1 % |
| Hazards | |
| R-phrases | R36/37/38 |
| S-phrases | S26, S36 |
| NFPA 704 |
0
1
0
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| (verify) (what is: /?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) |
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| Infobox references | |
Bromocresol Purple (BCP) or 5',5"-dibromo-o-cresolsulfophthalein, is a pH indicator. The most common solution is 0.04% aqueous.
| Bromocresol Purple (pH indicator) | ||
| below pH 5.2 | above pH 6.8 | |
| 5.2 | ↔ | 6.8 |
Besides its primary function as an indicator, Bromocresol Purple is used in medical laboratories to measure albumin, and as an addition to acid stop baths used in photographic processing as an indicator that the bath has reached neutral pH and needs to be replaced.