Arsenic
A heavy, brittle block of grey arsenic sits on a laboratory bench. Its density measures 5.73 grams per cubic centimeter. This specific form of the element dominates industrial use because it conducts electricity better than other versions. It possesses a double-layered crystal structure with interlocked six-membered rings. Weak bonds between these layers make the material soft enough to scratch with a fingernail. A Mohs hardness rating of 3.5 confirms this brittleness.
Contrast this solid metal with yellow arsenic. This waxy allotrope forms only when rapid cooling transforms arsenic vapor into a molecular tetrahedral shape. Yellow arsenic has a density of just 1.97 grams per cubic centimeter. It is the most volatile and toxic version known to science. Exposure to light causes it to transform back into the stable grey form within moments. Black arsenic exists as well but remains a poor electrical conductor compared to its grey counterpart.
Ancient Syriac speakers used the word zarnika to describe orpiment. Arabic scholars later adopted al-zarnīkh from Persian roots meaning gold-colored. Greek translators adapted this term into arsenikon. Latin speakers eventually created the modern English name arsenic. The linguistic journey reflects centuries of human fascination with the substance's golden hue in mineral form.
Jabir ibn Hayyan isolated elemental arsenic before the year 815 AD. Albertus Magnus achieved isolation again in 1250 by heating soap with arsenic trisulfide. Johann Schröder published two preparation methods in 1649. These early chemists worked without knowing the element would become the poison of kings. Ruling classes frequently used arsenic trioxide to eliminate rivals during the Renaissance era.
The Victorian period saw women consume white arsenic mixed with vinegar to achieve pale complexions. This practice led to the Bradford sweet poisoning incident in 1858. Twenty-one people died after consuming food adulterated with the compound. Napoleon Bonaparte may have succumbed to arsenic-laden wallpaper in his exile on Saint Helena. His death occurred in 1821 according to historical accounts.
Lead components in car batteries gain strength from a very small percentage of added arsenic. Dezincification of brass copper-zinc alloys reduces significantly when manufacturers add trace amounts of the metal. Phosphorus Deoxidized Arsenical Copper contains 0.3 percent arsenic for enhanced corrosion stability. Gallium arsenide serves as an important semiconductor material for integrated circuits.
Circuits made from gallium arsenide operate much faster than silicon-based alternatives but cost more to produce. The material possesses a direct bandgap allowing conversion of electrical energy directly into light. Laser diodes and LEDs utilize this property extensively. Cadmium arsenide functions as another II-V semiconductor option available to engineers.
China produced almost 70 percent of global white arsenic output in 2014. Morocco, Russia, and Belgium followed behind China in production rankings. Most refinement operations in the United States and Europe closed due to environmental concerns. Arsenic recovery primarily occurs from copper smelter dust where it acts as a main impurity.
Arsenic trioxide ranks number one on the United States Agency for Toxic Substances and Disease Registry list of hazardous substances published in 2001. The International Agency for Research on Cancer classifies all forms of arsenic as group one carcinogens. Exposure disrupts ATP production through inhibition of lipoic acid cofactors at active enzyme sites.
Hydrogen peroxide production increases significantly when arsenic competes with phosphate during oxidative phosphorylation. This metabolic interference leads to multi-system organ failure in severe poisoning cases. Long-term exposure links to bladder cancer, kidney cancer, liver cancer, prostate cancer, skin cancer, lung cancer, and nasal cavity cancer. The lethal human dose involves approximately 20 grams of ash from burnt treated wood.
British anti-lewisite dimercaprol treats chronic arsenic poisoning with doses ranging from 5 mg/kg up to 300 mg every four hours initially. Blood urine hair and nails tests detect presence but cannot predict future health outcomes. Chronic consumption compromises immune responses to infections like H1N1 swine flu according to laboratory mouse studies conducted by NIEHS-supported scientists.
Approximately 57 million people in the Bengal basin drink groundwater exceeding World Health Organization standards of 10 parts per billion. Bangladesh and neighboring countries face widespread arsenic poisoning due to natural mineral release into subsurface aquifers. A massive shallow tube well drinking-water program launched in the late twentieth century failed to test for arsenic content.
More than 60 million people in Pakistan receive water indicated as polluted by a 2017 Science report. Podgorski's team analyzed over 1200 samples finding that 66 percent exceeded WHO contamination limits. Residents of San Pedro de Atacama in Chile have developed genetic variants enhancing arsenic metabolism after centuries of exposure. This adaptation represents one of few documented cases of human evolution responding to environmental toxicity.
Over 250 million people across India face high levels of arsenic in groundwater according to IIT Kharagpur research. Twenty percent of China's provinces contain high concentrations potentially exposing 19 million people to hazardous drinking water. Parts of New England Michigan Wisconsin Minnesota and the Dakotas also hold significant groundwater concentrations within the United States.
Some bacteria obtain energy without oxygen by oxidizing various fuels while reducing arsenate to arsenite. Enzymes known as arsenate reductases facilitate this process under oxidative environmental conditions. Researchers discovered a strain designated GFAJ-1 capable of substituting arsenic for phosphorus in biomolecules when grown in an arsenic-rich phosphate-limited environment.
This claim published in Science generated widespread skepticism among scientists worldwide. Follow-up studies demonstrated that GFAJ-1 still requires phosphate to grow and does not incorporate arsenate into DNA biologically significantly. An independent investigation in 2012 found no detectable arsenate incorporated into the DNA backbone using sensitive purification techniques. The original paper formally retracted in 2025 citing lack of sufficient experimental support despite authors standing by their data.
The Chinese brake fern Pteris vittata hyperaccumulates arsenic from soil into its leaves. This plant has proposed use in phytoremediation strategies to clean contaminated sites. Some species of bacteria catalyze redox transformations converting toxic forms into less dangerous states through dissimilatory arsenate-respiring prokaryotes or chemoautotrophic arsenite oxidizers.
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Common questions
What is the density of grey arsenic?
Grey arsenic has a density of 5.73 grams per cubic centimeter.
When did Jabir ibn Hayyan isolate elemental arsenic?
Jabir ibn Hayyan isolated elemental arsenic before the year 815 AD.
How many people died in the Bradford sweet poisoning incident of 1858?
Twenty-one people died after consuming food adulterated with white arsenic during the Bradford sweet poisoning incident in 1858.
Which country produced almost 70 percent of global white arsenic output in 2014?
China produced almost 70 percent of global white arsenic output in 2014.
Why does gallium arsenide operate faster than silicon-based circuits?
Gallium arsenide operates much faster because it possesses a direct bandgap allowing conversion of electrical energy directly into light.
Did scientists confirm that bacteria can substitute arsenic for phosphorus in DNA?
Follow-up studies and an independent investigation in 2012 found no detectable arsenate incorporated into the DNA backbone, leading to the formal retraction of the original paper in 2025.