Molecular Structure of Phenylbenzimidazole sulfonic acid (CAS NO.27503-81-7):

IUPAC Name: 2-phenyl-3H-benzimidazole-5-sulfonic acid 
Empirical Formula: C₁₃H₁₀N₂O₃S
Molecular Weight: 274.2951
H bond acceptors: 5
H bond donors: 2
Freely Rotating Bonds: 2
Polar Surface Area: 69.57 Å²
Index of Refraction: 1.703
Molar Refractivity: 71.08 cm³
Molar Volume: 183.1 cm³
Surface Tension: 72.3 dyne/cm
Density: 1.497 g/cm³
Melting point: 300 °C
Water Solubility: soluble
Merck: 3593
BRN: 922664
InChI
InChI=1/C13H10N2O3S/c16-19(17,18)10-6-7-11-12(8-10)15-13(14-11)9-4-2-1-3-5-9/h1-8H,(H,14,15)(H,16,17,18)
Smiles
c12c([nH]c(n1)c1ccccc1)ccc(c2)S(O)(=O)=O
EINECS: 248-502-0
Product Categories: Organic acids; BenzimidazolesPolymer Science; Building Blocks; Heterocyclic Building Blocks; Polymer Additives; Stabilizers

Hazard Codes: Xi,C
Risk Statements: 36/37/38
R36/37/38:Irritating to eyes, respiratory system and skin.
Safety Statements: 26-36
S26: In case of contact with eyes, rinse immediately with plenty of water and seek medical advice. 
S36:Wear suitable protective clothing.
HS Code: 29339990

  Phenylbenzimidazole sulfonic acid , with CAS number of 27503-81-7, can be called 1H-Benzimidazole-5-sulfonicacid, 2-phenyl- (9CI) ; 5-Benzimidazolesulfonic acid, 2-phenyl- (8CI) ; 2-Phenyl-5-sulfobenzimidazole ; 2-Phenylbenzimidazole-5-sulfonic acid . It is a white fine crystalline powder.