Empirical Formula: C₇H₅ClN₂ 
Molecular Weight: 152.581
Nominal Mass: 152 Da
Average Mass: 152.581 Da
Monoisotopic Mass: 152.014126 Da
Index of Refraction: 1.703 
Molar Refractivity: 41.51 cm³ 
Molar Volume: 107 cm³ 
Surface Tension: 62.2 dyne/cm 
Density: 1.425 g/cm³  
Melting point: 174-176 °C
Structure of 4-Chloro-7-azaindole (CAS NO.55052-28-3):
                       
Systematic Name: 4-Chloro-1H-pyrrolo[2,3-b]pyridine
SMILES: Clc1ccnc2c1ccn2 
InChI: InChI=1/C7H5ClN2/c8-6-2-4-10-7-5(6)1-3-9-7/h1-4H,(H,9,10) 
InChIKey: HNTZVGMWXCFCTA-UHFFFAOYAJ
Std. InChI: InChI=1S/C7H5ClN2/c8-6-2-4-10-7-5(6)1-3-9-7/h1-4H,(H,9,10) 
Std. InChIKey: HNTZVGMWXCFCTA-UHFFFAOYSA-N
Product Category of 4-Chloro-7-azaindole (CAS NO.55052-28-3): Various Intermediates;Heterocycles;Indole Derivatives;Intermediates

 4-Chloro-7-azaindole (CAS NO.55052-28-3) is a useful intermediate for drug discovery research.

The Hazard Codes:  Xi,Xn
The Risk Statements:
22:  Harmful if swallowed 
41:  Risk of serious damage to eyes 
37/38:  Irritating to respiratory system and skin 
The Safety Statements:
26:  In case of contact with eyes, rinse immediately with plenty of water and seek medical advice 
39:  Wear eye/face protection 
RIDADR: UN 2811 6.1/PG 3

 4-Chloro-7-azaindole , its cas register number is 55052-28-3. It also can be called 4-Chloro-1H-pyrrolo[2,3-b]pyridine .