Lewisite 2 (L-2) is an organoarsenic chemical weapon with the formula AsCl(CH=CHCl)₂. It is similar to lewisite 1 and lewisite 3 and was first synthesized in 1904 by Julius Arthur Nieuwland.McNutt, Patrick M., and Tracey L. Hamilton. "Ocular toxicity of chemical warfare agents." Handbook of Toxicology of Chemical Warfare Agents. Academic Press, 2015. 535-555. It is usually found as a mixture of 2-chlorovinylarsonous dichloride (lewisite 1) as well as bis(2-chloroethenyl) arsinous chloride (lewisite 2) and tris(2-chlorovinyl)arsine (lewisite 3). Pure lewisite 1 is an oily, colorless liquid, however, the impure mixture can appear amber to black with an odor distinct to

geraniums ''Pelargonium'' () is a genus of flowering plants that includes about 280 species of perennials, succulents, and shrubs, commonly called geraniums, pelargoniums, or storksbills. '' Geranium'' is also the botanical name and common name of a separ ...

Synthesis

Lewisite 2 is made as a

byproduct A by-product or byproduct is a secondary product derived from a production process, manufacturing process or chemical reaction; it is not the primary product or service being produced. A by-product can be useful and marketable or it can be consid ...

along with lewisite 3 in the reaction that makes lewisite 1.Chemistry of Sulfur Mustard and Lewisite https://www.ncbi.nlm.nih.gov/books/NBK236079/

Acetylene Acetylene (systematic name: ethyne) is the chemical compound with the formula and structure . It is a hydrocarbon and the simplest alkyne. This colorless gas is widely used as a fuel and a chemical building block. It is unstable in its pure ...

reacts with AsCl3 in hydrochloric acid solution, with mercuric chloride as a catalyst, to give lewisite in 80 to 85% yield. :AsCl₃ + C₂H₂ → (ClCH=CH)AsCl₂ Lewisite 2 is formed when there are two additions of

acetylene Acetylene (systematic name: ethyne) is the chemical compound with the formula and structure . It is a hydrocarbon and the simplest alkyne. This colorless gas is widely used as a fuel and a chemical building block. It is unstable in its pure ...

to the arsenic center instead of one like the reaction seen above where only lewisite one is shown.

Exposure

Adverse health effects caused by lewisite can vary and are dependent on; the amount people are exposed to and, the amount of time someone is exposed to it. Lewisite immediately damages the skin, eyes, and respiratory tract and is a strong irritant and

blistering agent A blister agent (or vesicant), is a chemical compound that causes severe skin, eye and mucosal pain and irritation. They are named for their ability to cause severe chemical burns, resulting in painful water blisters on the bodies of those affec ...

. Due to its arsenic center, lewisite may also cause problems similar to arsenic poisonings like stomach ailments and low blood pressure.

Inhalation

Inhalation, the most common route of exposure, causes a burning pain and irritation throughout the respiratory tract, nosebleed (epistaxis),

laryngitis Laryngitis is inflammation of the larynx (voice box). Symptoms often include a hoarse voice and may include fever, cough, pain in the front of the neck, and trouble swallowing. Typically, these last under two weeks. Laryngitis is categorised ...

, sneezing, coughing, vomiting, difficult breathing ( dyspnea). From one acute exposure, someone who has inhaled lewisite can develop chronic respiratory disease. In severe cases of exposure, can cause fatal pulmonary edema, pneumonitis, or respiratory failure.

Ingestion

Ingestion results in severe pain, nausea, vomiting, and tissue damage. Those exposed to lewisite can develop refractory hypotension (low blood pressure) known as Lewisite shock, as well as some features of arsenic toxicity. Lewisite causes physical damage to capillaries, which then become leaky, meaning that there is not enough blood volume to maintain blood pressure, a condition called

hypovolemia Hypovolemia, also known as volume depletion or volume contraction, is a state of abnormally low extracellular fluid in the body. This may be due to either a loss of both salt and water or a decrease in blood volume. Hypovolemia refers to the los ...

. When the blood pressure is low, the kidneys may not receive enough oxygen and can be

damaged Damage is any change in a thing, often a physical object, that degrades it away from its initial state. It can broadly be defined as "changes introduced into a system that adversely affect its current or future performance".Farrar, C.R., Sohn, H. ...

Eye exposure

The results of eye exposure can range from stinging, burning pain and strong irritation to

blister A blister is a small pocket of body fluid (lymph, serum, plasma, blood, or pus) within the upper layers of the skin, usually caused by forceful rubbing (friction), burning, freezing, chemical exposure or infection. Most blisters are filled wi ...

ing and scarring of the cornea, along with

blepharospasm Blepharospasm is any abnormal contraction of the orbicularis oculi muscle. The condition should be distinguished from the more common, and milder, involuntary quivering of an eyelid, known as myokymia, or fasciculation. In most cases, blepharosp ...

, lacrimation, and edema of the eyelids and periorbital area. Eye exposure to lewisite can cause permanent visual impairment or blindness. The eyes can swell shut, which can keep the eyes safe from further exposure. The most severe consequences of eye exposure to lewisite are globe perforation and blindness. Generalised symptoms also include restlessness, weakness, hypothermia and low blood pressure.

Chronic exposure

Chronic exposure to lewisite can cause arsenic poisoning and development of a lewisite allergy. It can also cause various long-term illnesses or permanent damage to organs, depending on where the exposure has occurred, including conjunctivitis, aversion to light ( photophobia), visual impairment, double vision ( diplopia), tearing ( lacrimation), dry mucous membranes, garlic breath, burning pain in the nose and mouth, toxic encephalopathy, peripheral neuropathy, seizures, nausea, vomiting, chronic obstructive pulmonary disease (COPD), bronchitis, dermatitis, skin ulcers, basal cell carcinoma, and

squamous cell carcinoma Squamous-cell carcinomas (SCCs), also known as epidermoid carcinomas, comprise a number of different types of cancer that begin in squamous cells. These cells form on the surface of the skin, on the lining of hollow organs in the body, and on the ...

Treatment

Basic first aid for lewisite exposure is

decontamination Decontamination (sometimes abbreviated as decon, dcon, or decontam) is the process of removing contaminants on an object or area, including chemicals, micro-organisms or radioactive substances. This may be achieved by chemical reaction, disinfecti ...

and irrigation of any areas that have been exposed, and when necessary

airway management Airway management includes a set of maneuvers and medical procedures performed to prevent and relieve airway obstruction. This ensures an open pathway for gas exchange between a patient's lungs and the atmosphere. This is accomplished by either cl ...

assisted ventilation Mechanical ventilation, assisted ventilation or intermittent mandatory ventilation (IMV), is the medical term for using a machine called a ventilator to fully or partially provide artificial ventilation. Mechanical ventilation helps move air i ...

, and monitoring of vital signs. Dimercaprol, also called British anti-lewisite, is the antidote for lewisite. It can be injected to prevent systemic toxicity, but will not prevent injury to the skin, eyes, or mucous membranes. Chemically, dimercaprol is a

chelating agent Chelation is a type of bonding of ions and molecules to metal ions. It involves the formation or presence of two or more separate coordinate bonds between a polydentate (multiple bonded) ligand and a single central metal atom. These ligands are ...

that binds to the arsenic in lewisite.Vilensky, Joel A., and Kent Redman. "British anti-Lewisite (dimercaprol): an amazing history." Annals of emergency medicine 41.3 (2003): 378-383. It is contraindicated in those with

peanut allergies Peanut allergy is a type of food allergy to peanuts. It is different from tree nut allergies, because peanuts are legumes and not true nuts. Physical symptoms of allergic reaction can include itchiness, hives, swelling, eczema, sneezing, asth ...

References

{{Reflist Arsenical vesicants Organoarsenic chlorides Alkene derivatives Arsenic(III) compounds