Basic Information

National standard number: 61007

CAS No.：1327-53-3

MDL No.: MFCD00003433

EINECS No.：215-481-4

RTECS No.: CG3325000

PubChem No.: 24852110

InChI: InChI=1/2As.3O/q2*+3;3*-2

Also known as: Letterite

Physical and chemical properties

Properties: There are three states of amorphous, isometric and monoclinic crystals or colorless powder. They are easily reduced as well as oxidized.

Structure diagram of arsenic trioxide

Structure diagram of arsenic trioxide

Melting point: arsenic wah 275℃ white arsenite 313℃

Boiling point: 457.2°C [2]

Vapor pressure: 13.33kPa (332.5℃)

Solubility: slightly soluble in water (at 25 °, 1g of the substance can be dissolved in greater than or equal to 100ml and less than 1000ml of water), soluble in acid, alkali

Density: relative density (water=1) 3.86

Hazardous mark: 13 (inorganic highly toxic)

Properties: Odorless. White powder or crystal. There are three crystalline forms: monoclinic crystal relative density 4.15, 193℃ sublimation; cubic crystal relative density 3.865; amorphous body relative density 3.738, melting point 312.3℃. Slightly soluble in water to produce arsenious acid. Monoclinic and cubic crystals are soluble in ethanol, acids and bases; amorphous body is soluble in acids and bases, but insoluble in ethanol. The industrial product is slightly red, gray or yellow depending on the impurities it contains.

The main use is for the extraction of elemental arsenic. It is the raw material for smelting arsenic alloy and manufacturing semiconductors. The glass industry is used as clarifying agent and decolorizing agent to enhance the translucency of glass products. The leather industry is used to make sodium arsenite as leather preservation agent. In agriculture, it is used as insecticide, disinfectant and rust remover for pest control, and also used as raw material for other pesticides containing arsenic. Also used in paint and pigment industry. It can be used as chemical reagent. Also used in gas desulfurization, wood corrosion, boiler scale prevention, and glass and enamel.

Amorphous (Vitreous arsenic) colorless and amorphous glassy substance. Unstable, can slowly become isometric crystal system.

Arsenolite (Arsenic) Small crystals (powder) of white isometric octahedra. It is the most stable even at room temperature. It sublimates at 135°C and transforms into monoclinic crystal system at 221°C.

White arsenolite (Claudetite) is a colorless needle-like crystal of monoclinic crystal system, which is unstable at temperatures above 221°C.

Main uses

Used for refining elemental arsenic. It is the raw material for smelting arsenic alloy and manufacturing semiconductors.

Used in glass industry as clarifying agent and decolorizing agent to enhance the light transmission of glass products.

In agriculture, it is used as disinfectant and rust remover for pest control, and also used as raw material for other pesticides containing arsenic.

Used in the manufacture of paints and dyes. It can be used as chemical reagent. Also used in gas desulfurization, wood corrosion, boiler scale prevention, and ceramics and enamel.

Used as analytical reagent, such as as a benchmark reagent, reducing agent. Chlorine gas absorber. Also used in the preparation of arsenite, as a preservative.

Used in glass, enamel, pigment industry and preparation of drugs, insecticides, leather preservatives, etc.

Safety matters

Packed in wooden boxes lined with two layers of solid paper bags or polyethylene plastic bags, tied with wire or iron outside, net weight 50kg per box, with obvious "highly toxic" mark on the package. It is inorganic and highly toxic, hazard code: GB 6.1 class 61007. highly toxic A1204. UN NO.1561; IMDG CODE 6078 page, class 6.1. It should be stored in a ventilated and dry warehouse. Containers must be sealed and stored in isolation from edible raw materials to prevent spills and moisture. Management should be strengthened. Handling personnel should change their clothes immediately after work and wash their hands with water to avoid accidentally entering the mouth. In case of fire, water and sand can be used to put out the fire. Toxicity and protection: Lethal dose (by mouth) 60mg. chronic poisoning can cause gastrointestinal disorders, leading to periodic colitis, chronic hepatitis, and in severe cases, liver sclerosis. Damage to mucous membranes, skin, nervous system, kidney and heart. In dust poisoning, changes in mucous membranes, eyes and skin are first seen. In acute oral poisoning, measures are taken to induce vomiting, gastric lavage, and intravenous injection of glucose solution. For skin disorders, ascorbic acid and intravenous sodium thiosulfate are available. The maximum permissible concentration is 0.3mg/m3. When operating, wear anti-toxic masks, protective glasses, dustproof work clothes and underwear, gloves made of rubber, plastic or strong cloth, and strictly observe personal hygiene measures.

Environmental impact

Health hazards

Intrusion route: inhalation, ingestion.

Health hazard: It mainly affects the nervous system and capillary permeability, and has an irritating effect on skin and mucous membrane.

Acute poisoning: Oral poisoning with nausea, vomiting, abdominal pain, stool sometimes mixed with blood, painful spasms of limbs, oliguria, anuric coma, convulsions, respiratory paralysis and death. Peripheral neuropathy can occur within 1-3 weeks of acute poisoning. Toxic myocarditis and hepatitis can occur. Large amounts of inhalation can also cause acute poisoning, but the digestive symptoms are light and m's lines appear on the finger (toe) nails.

Chronic toxicity: digestive symptoms, liver and kidney damage, skin hyperpigmentation, hyperkeratosis or warty growths, and multiple peripheral neuritis. May cause lung cancer and skin cancer.

Toxicological information

Acute toxicity: LD50: 10mg/kg (oral in rats); 20mg/kg (oral in mice).

Sub-acute and chronic toxicity: rats ingested 150mg/(kg-d) for 6.5 months, with mild effects on growth and development, significant increase in liver and kidney weight, but normal liver and kidney function and blood routine; below 30mg/kg, no pathological changes in all major organs of animals.

Mutagenicity: DNA inhibition: 500 μmol/L in human Hela cells.

Cytogenetic analysis: human leukocytes 1200 nmol/L.

Teratogenicity: Inhalation of the lowest toxic dose of 28,500μg/m (4h) in mice from 9 to 12 d of gestation caused malformations in the development of the musculoskeletal system. The lowest toxic dose of 1650μg/kg was administered orally to mice from 7 to 17 d of gestation, resulting in malformation of the central nervous system. The lowest oral dose of 8250μg/kg in mice from 7 to 17 d of pregnancy caused malformation of the immune and reticuloendothelial systems.

Carcinogenicity: IARC Carcinogenicity Review: G1, confirmed human carcinogen.

Other: Minimum toxic concentration by inhalation (TCLo) in mice: 28500μg/m (4h) (9~12d gestation) caused cytological alterations and normal musculoskeletal development.

Hazardous properties: If exposed to high heat, sublimation produces a highly toxic gas.

Combustion (decomposition) products: arsenic oxide.

Ecological information

Ecotoxicity:

LC50: 8.33mg/L (48h) (salmon); 0.038mg/L (24h) (daphnia).

EC50: 31.43~73.73mg/L (5, 15, 30min) (Luminous bacteria, Microtox test).

Other harmful effects:

The substance is harmful to the environment and special attention should be given to fish and mammals.

Emergency treatment

Spill response

Isolate the contaminated area of the spill and restrict access. Recommend emergency personnel to wear self-contained positive pressure respirators and hazmat suits. Do not come into direct contact with the spill. Small spills: Avoid dust and collect in dry, clean, covered containers with a clean shovel. Large spills: Cover with plastic sheeting and canvas to reduce fly-away. Then collect, recycle or transport to waste disposal site for disposal.

Protective measures

Mechanism of arsenic reduction

Mechanism of arsenic reduction

Respiratory protection: When you may be exposed to its dust, you should wear a hood-type electric air-fed filtered dust respirator. If necessary, wear an air respirator.

Eye protection: Protection has been made in respiratory protection.

Body protection: Wear a one-piece rubberized gas-protective suit.

Hand protection: Wear rubber gloves.

Other: Smoking, eating and drinking are prohibited at the work site. After work, clean thoroughly. Separate storage of clothes contaminated by toxic substances, wash and prepare for use. Implement pre-employment and regular medical examinations.

First aid measures

Skin contact: Remove contaminated clothing, rinse skin thoroughly with soapy water and water, seek medical attention.

Eye contact: Lift eyelids, flush with running water or saline, seek medical attention.

Inhalation: Quickly remove from the scene to fresh air. Keep airway open. If breathing is difficult, give oxygen infusion. If breathing stops, give immediate artificial respiration. Seek medical attention.

Ingestion: induce vomiting. Gastric lavage give milk or egg white. Seek medical attention.

Fire-fighting methods: Firefighters must wear full-body special protective clothing. Extinguishing agents: dry powder, water, sand and earth.

Environmental Management

Environmental standards

China (TJ36-79): The maximum permissible concentration of harmful substances in the air of the workshop is 0.287mg/m3.

Soviet Union (1975)) Maximum allowable concentration of harmful substances in water body 0.05mg/L (in As3+).

Monitoring methods

Laboratory monitoring method:

Silver colorimetric method of diethyl dithiocarbamate "Determination method of harmful substances in air" (2nd edition), edited by Hang Shiping.

Hydride Atomic Absorption Method: Determination of Hazardous Substances in Air (2nd edition), edited by Hang Shiping.

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Storage method

Store in a cool, well-ventilated special warehouse, and implement the system of "double receipt and delivery, double storage". Keep away from fire and heat source. Packed and sealed. It should be stored separately from oxidizers, acids, halogens and edible chemicals, and should not be mixed. The storage area should be equipped with suitable materials to shelter leaks.

Common Rumors

Corresponding to the long history of arsenic trioxide, the method of detecting poison by silver needle was widely used in the ancient cases in China. Is it true that arsenic trioxide can react with silver? The answer is: No.

Due to poor smelting techniques and crude technology in ancient times, the arsenic made often contains a large amount of sulfide. Sulfide and silver reaction, the resulting black silver sulfide (Ag2S) attached to the surface of the silver needle, the silver needle so black. In other words, the silver needle test method of poison actually detects the sulfur impurities in the arsenic only, and not the detection of arsenic trioxide itself. Therefore, the successful application of silver needles to detect poison in ancient times is purely coincidental.

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