|Other names||Tear Gas|
|Molar mass||Molar mass::188.613 g/mol|
|Appearance|| White crystalline when solid,
otherwise an aerosol
|CAS number||CAS number::2698-41-1|
|Density and phase||[[Density::1.04 g/cm3]], ?|
|Melting point||Melting point::95°C|
|Boiling point||Boiling point::312.5°C|
|MSDS||Material safety data sheet|
|Main hazards|| Skin irritant. Coughing/ choking hazard,
can cause heart of liver damage.
CS gas is a chemical aerosol used for crowd control, which is known by the chemical name is 2-chlorobenzalmalononitrile. It is one of a group of substances commonly referred to as a "tear gas". It causes skin irritation on any wet part of the body including the eyes and facial area. Tear gas is also listed as non-lethal. CS gas, if inhaled deeply, can cause damage to the heart and liver as well as lungs and can therefore be lethal, but it's generally considered non-lethal. CS gas was originally tested on animals, but it had no effect because of their "protection by fur and their under-developed tear ducts". 
CS is synthesized by the reaction of 2-chlorobenzaldehyde and malononitrile via the Knoevenagel condensation: ClC6H4CHO + H2C(CN)2 → ClC6H4CHC(CN)2 + H2O. Two Americans by the names of Ben Corson and Roger Stoughton discovered it in 1928 and the chemical was named after the first letter of each of their last names. The production steps are still the same as when it was discovered. CS is a solid at room temperature and must be heated to form a gas. The gas or solid dissolves in water and is no longer harmful. However, in powder form, it can be very dangerous. To change the solid into a gas, you can heat it, dissolve it in an organic solvent, disperse the powder, or spread it by hot gases in an explosion.
CS Gas is primarily used for one reason, crowd control. There are two types of concentrations: 3% and 6%. The 3% is used for training purposes. The different military branches put their personnel through the training that takes place in a gas chamber. You must remember to wash off the gas from your skin because if not rinsed, it can cause boils and burns since it is a skin irritant. Riot police use the 6% concentration of CS gas to deter protesters and other types of rallies. Police have used the gas in many countries and the Chemical Weapons Convention has banned the use in war to all countries and only 5 have yet to sign the treaty: Angola, Egypt, North Korea, Somalia, and Syria.  The Chemical Weapons Convention wanted to ban CS gas for use in war because they feared that some countries would retaliate with nerve agents like Saddam Hussein's mustard gas.
CS gas can be very painful if not rinsed off the body after coming in contact with it. CS is a skin irritant, causing itching, stinging and erythema, and may cause blistering and allergic contact dermatitis. Burning and irritation to eyes may occur with lacrimation and accompanying blepharospasm. These are symptoms of being on contact with the skin and eyes. Respiratory symptoms are different and they consist of salivation, coughing, choking, and a feeling of chest tightness. It may cause reactive airway disease syndrome requiring medical intervention. If you believe you have come in contact with the gas, shower immediately to rinse it off your body.
A man volunteers to get sprayed with CS gas. 
- Neilands, J.B. Orthochlorobenzylidenemalononitrile ClC6H4CHCCN(CN)2 . Zarc. Web. Published 1972.
- Heinrich, Uwe. Possible lethal effects of CS tear gas on Possible lethal effects of CS tear gas on Branch Davidians during the Branch Davidians during the FBI raid on the Mount Carmel compound FBI raid on the Mount Carmel compound near Waco, Texas near Waco. Veritagiustizia. Web. September 2000.
- Palmer, Brian. Why Isn't Tear Gas Illegal?. Slate. Web. February 11, 2010.
- Fouad,T. Tahrir, How to deal with tear gas. democrati.net. Web. November 21, 2011.
- iIMeccaIi. The Effects of CS Gas. Youtube. Web. October 21, 2010.