The Molecular Structure of 2-Chloro-3-cyanopyrazine (CAS NO.55557-52-3): 

Molecular Formula: C₅H₂ClN₃
Molecular Weight: 139.54
Melting point: 45-47°C
Boiling Point: 264.1 °C at 760 mmHg
Flash Point: 113.5 °C
Index of Refraction: 1.568
Molar Refractivity: 31.74 cm³
Molar Volume: 97 cm³
Polarizability: 12.58*10^-24cm³
Surface Tension: 70.6 dyne/cm
Density: 1.43 g/cm³
H bond acceptors: 3
H bond donors: 0
Freely Rotating Bonds: 0
Polar Surface Area: 49.57Ų
Enthalpy of Vaporization: 50.2 kJ/mol
Vapour Pressure: 0.00989 mmHg at 25°C
IUPAC Name: 3-chloropyrazine-2-carbonitrile 
Product Categories: pharmacetical; Pyrazines, Pyrimidines & Pyridazines; Pyridazine series; Pyrazine; Pyrazines, Pyrimidines & Pyridazines

The Hazard Codes of 2-Chloro-3-cyanopyrazine (CAS NO.55557-52-3): Xn
Hazard Note: Harmful
The Risk Statements information of 2-Chloro-3-cyanopyrazine (CAS NO.55557-52-3):
20/21/22:  Harmful by inhalation, in contact with skin and if swallowed 
36/37/38:  Irritating to eyes, respiratory system and skin 
The Safety Statements information of 2-Chloro-3-cyanopyrazine (CAS NO.55557-52-3):
26:  In case of contact with eyes, rinse immediately with plenty of water and seek medical advice 
36/37/39:  Wear suitable protective clothing, gloves and eye/face protection 
RIDADR: 3276

 2-Chloro-3-cyanopyrazine , its cas register number is 55557-52-3. It also can be called 3-chloropyrazine-2-carbonitrile ; 3-chloro-2-cyanopyrazine ; 3-chloropyrazin-2-carbonitrile ; 3-chloro-2-pyrazinecarbonitrile ; 3-chloropyrazine-2-carbonitrile, 95+% ; 2-chloro-3-cyanopyrazine 95%+ and so on.