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Name: Mercury(II) Iodide
Chemical Formula: HgI2
Synonym: Mercuric iodide
Appearance: Bright red or orange-red crystalline solid
Odor: Odorless
Common Uses: Laboratory reagent, some uses in x-ray and semiconductor industries
Health Risks: Highly toxic due to mercury content, risk of severe harm when inhaled, ingested, or in contact with skin or eyes. Chronic exposure leads to mercury poisoning, which damages kidneys, nerves, and brain function. Can trigger allergic reactions and severe skin irritation.
Environmental Hazard: Persistent pollutant, accumulates in water systems, poisons aquatic life, moves up the food chain. Once released, it poses lasting risks.
Physical Hazards: Stable under normal storage, but can form toxic gases when heated.
Main Ingredient: Mercury(II) iodide — roughly 100% by weight for laboratory-grade samples.
Hazardous Constituents: Both mercury and iodine within the molecule carry significant toxicity. No safe exposure threshold.
Inhalation: Move affected person outside to fresh air straight away. Seek immediate medical help. Exposure can harm lungs and trigger systemic toxicity.
Skin Contact: Rinse thoroughly with soap and water. Remove and wash contaminated clothing. Even small exposures can cause skin burns and allergic reactions.
Eye Contact: Rinse with water gently, keeping eyelids open. Avoid rubbing. Call for medical assistance right away—eye exposure risks permanent injury.
Ingestion: Do not induce vomiting. Rinse mouth. Get emergency medical attention. Mercury compounds are deadly even in tiny amounts.
Flammability: In itself, mercury(II) iodide does not catch fire easily, but heating can release highly toxic mercury and iodine vapors.
Firefighting Tips: Use respirators and full protection if working near a fire. Water spray can control dust, but avoid direct water spray on spilled product. Firefighters need to avoid breathing the smoke.
Suitable Extinguishers: Dry chemical, carbon dioxide, or foam for surrounding fires. Avoid methods that spread contamination.
Personal Protection: Wear gloves, goggles, and an appropriate respirator. Mercury compounds demand strict controls—never sweep or create dust.
Containment: Scoop up carefully, using damp paper or disposable material. Keep the spill contained and prevent it entering any drains or soil.
Clean-Up: Place waste in sealed containers for hazardous waste disposal. Clean surface thoroughly after removal, using methods that avoid spreading dust.
Handling: Only open in a fume hood or ventilated area, with gloves and eye protection. Keep containers tightly closed. Never eat, drink, or smoke around this chemical. Mercury’s risk is slow and cumulative; careless handling brings long-term danger.
Storage: Store away from heat, direct sunlight, strong acids, and bases. Put containers in secure, locked storage labeled for highly toxic materials, well away from living or food areas.
Ventilation: Use enclosed systems or local exhaust. Never rely on general room air movement.
Personal Protection: Impermeable gloves, chemical splash goggles, and full-body covering are required. Respirators with mercury vapor cartridges needed if dust or fumes are generated.
Exposure Limits: OSHA and ACGIH set strict limits for mercury exposure. Even trace levels are too high for regular, unprotected handling.
Hygiene Measures: Wash hands and face thoroughly after working with mercury compounds. Contaminated clothing should never leave the workspace.
Appearance: Red or orange-red crystalline solid
Odor: Odorless
Molecular Weight: 454.4 g/mol
Melting Point: 259°C (decomposes)
Solubility: Nearly insoluble in water; more soluble in alcohol and solutions with alkali iodides
Density: 6.4 g/cm³
Vapor Pressure: Negligible at room temperature; hazardous fumes generate if overheated
Chemical Stability: Stable under normal conditions, but light and heat slowly decompose the compound.
Reactivity: Reacts dangerously with strong acids, bases, and reducing agents. Avoid mixing with anything but compatible glass containers and dedicated tools.
Hazardous Decomposition: Heating generates mercury and iodine vapors, both highly poisonous.
Acute Exposure: Inhalation, ingestion, or skin contact can lead to immediate poisoning. Symptoms range from headache, nausea, and metallic taste, to kidney failure and death.
Chronic Exposure: Mercury builds up in the body. Chronic poisoning damages nervous system, kidneys, and digestive system. Behavioral changes and tremors are classic symptoms of long-term exposure.
Routes of Entry: Absorbed via inhalation, ingestion, and to some extent through skin. No safe level of exposure—risk of harm rises with even short-term contact.
Aquatic Toxicity: Mercury poisoning devastates aquatic ecosystems. Even microgram quantities wipe out fish and disrupt food webs. Iodide compounds further poison plants and animals.
Persistence: Once released, mercury stays in soils and sediments for decades. Methylation by bacteria turns it into even more hazardous methylmercury, which accumulates in living organisms.
Bioaccumulation: Moves up the food chain, concentrating in predatory fish and mammals, reaching humans who eat contaminated seafood.
Hazardous Waste: Treat all waste and contaminated material as hazardous. Special licensing and strict protocols apply to mercury waste disposal.
Best Practices: Never dump down the drain or in the trash. Use designated chemical waste containers. Only qualified waste handlers should carry out disposal, with full documentation for environmental compliance.
UN Identification: Carriage under strict hazardous substance rules. Only certified handlers can ship.
Packing and Labeling: Requires sturdy, leak-proof, clearly labeled containers. Avoid shocks, breakage, or atmosphere exposure.
Legal Status: International and national laws prohibit unauthorized shipping. Immediate reporting applies for any accidents or exposure events in transit.
Regulation: Mercury(II) iodide classified as a highly hazardous substance by international, national, and local regulators. Legislation restricts its use, distribution, and disposal across many sectors.
Worker Safety: Strict occupational limits on exposure, and mandatory reporting of use and stockpiling.
Public Health: Safety warnings, public education, and even outright bans in some industries reflect how health authorities view the dangers of this chemical.
