Chlorine
Formula :  CL2
Description :  Discovered in 1774  by  Carl Wilhem Scheele
                        Its name came from the greec Khloros (green)
                        Powerful vapor that irritates eyes and respiratory system, toxic for 
                        skin and eyes.
                        State : Gas
                        Odor : Bleaching liquid (Base on Chlorine)
                        Color : No (Green if pure)
                        Type : Chocking agent
                        Persistency: Short 
                        Class : Halogen
                        Density: 3,214 g/cm3
                        Boiling point : -34,6° C     Melting point : -100,98° C
                        Crystal structure : Orthorhombic
                        Decomposition point: Over 1000° C
                        Remark : little used as a military chemical agent   
Symptoms :  Irritates eyes, affects upper and lower respiratory systems 
                     Irritate wounds and cuts
                     Mask and respirator
First-Aid : Inhale a small quantity or clean with amonia solution