Antimony is mixed into alloys and used in lead storage batteries, solder, sheet and pipe metal, motor bearings, castings, semiconductors, and pewter. Antimony oxide is added to textiles, plastics, rubber, adhesives, pigments and paper to prevent them from catching fire. It is also used in paints, ceramics, ammunition and fireworks, and as enamels for plastics, metal, and glass. Antimony compounds also find medical uses.
Substance name: Antimony & compounds
CASR number: 7440-36-0
Molecular formula: Sb
Synonyms: Stibium, Regulus of antimony, Antimony regulus, Antimony black, C.I. 77050, Antimony bar
Brittle, silvery-white metalloid with low thermal and electrical conductivity, displaying both metallic and non-metallic characteristics. Antimony may also exist as unstable yellow crystalline, or amorphous black, allotropes.
Atomic Number: 51
Atomic Mass: 121.8
Melting Point: 631°C
Boiling Point: about 1750°C
Specific Gravity: 6.7
Vapour Density: 4.2
Antimony metal is stable under ordinary conditions and is not readily attacked by air or water. It reacts with strong oxidisers, acids and halogenated acids. Generally, antimony is not used alone. It can be mixed with other metals to form antimony alloys or used to form antimony compounds where antimony may exist in oxidation states of -III, +III or +V. The most important compounds are antimony oxides, i.e. antimony trioxide and antimony pentoxide. Antimony trioxide is slightly soluble in water. Other less-important antimony compounds include antimony pentasulfide, antimony chloride, antimony potassium tartrate, antimony trichloride, antimony trisulfide and antimony hydride (or stibine).
The National Pollutant Inventory (NPI) holds data for all sources of antimony emissions in Australia.
Antimony is a non-essential element in humans, animals and plants. Its toxicity highly depends upon chemical form and oxidation state with +III compounds exerting greater toxicity than +V compounds. Antimony compounds show toxic properties similar to those of arsenic. This depends on how much antimony a person has been exposed to, for how long, and current state of health. Exposure to high levels of antimony can result in a variety of adverse health effects. Breathing high levels for a long time can irritate eyes and lungs and can cause heart and lung problems, stomach pain, diarrhoea, vomiting, and stomach ulcers. Ingesting large doses of antimony can cause vomiting. Antimony can irritate the skin on prolonged contact.
Antimony can have beneficial effects when used for medical reasons. It has been used as a medicine to treat people infected with tropical parasites. It is not known whether elemental antimony will cause cancer in people. Human studies are inconclusive as to its human carcinogenicity, hence antimony has not been classified. Antimony trioxide is carcinogenic in animal experiments and is regarded by the International Association for Research into Cancer (IARC) as 'possibly carcinogenic to humans'. Worksafe Australia classifies antimony as hazardous.
Entering the body
Antimony can be inhaled or ingested.
Because antimony is found naturally in the environment, the general population is exposed to low levels of it every day, primarily in food, drinking water, and air. Industries such as smelters, coal-fired plants, and refuse incinerators can release it in air, resulting in higher levels of antimony in the air, water, and soil. Workers in these industries may be exposed to higher levels.
Workplace exposure standards
Safe Work Australia sets the workplace exposure standard for antimony and compounds through the workplace exposure standards for airborne contaminants:
- Maximum eight hour time weighted average (TWA): 0.5 mg/m3
These standards are only appropriate for use in workplaces and are not limited to any specific industry or operation. Make sure you understand how to interpret the standards before you use them.
Drinking water guidelines
The Australian Drinking Water Guidelines include the following guidelines for acceptable water quality:
- Maximum of 0.003 milligrams per litre of water for health purposes
Most antimony compounds show little or no tendency to accumulate in aquatic life. Some plants, mosses, lichens and fungi are able to accumulate antimony compounds.
Entering the environment
Little information is available on the transformations and transport of antimony in various environmental media (e.g. air, water, soil). The mobility of antimony in soils is not clearly understood. Some studies indicate that antimony is highly mobile, while others conclude that it strongly adsorbs to soil. In water, it usually adheres to sediments. Most antimony compounds show little or no tendency to accumulate in aquatic life.
Where it ends up
When released to air, antimony can attach itself to very small particles and may stay in the atmosphere for many days. It may be possible for these particles to be transported over long distances before they eventually settle. In soil, antimony is strongly attached to particles containing iron, manganese, or aluminium. Other factors influencing the strength of its adsorption are pH, organic matter content and oxidation state of the particular salt. Antimony is found at low levels in some rivers, lakes, and streams.
Australian Water Quality Guidelines for Fresh and Marine Waters: (ANZECC, 1992):
Maximum of 30 micrograms/L (i.e. 0.00003 g/L) and 500 micrograms/L (i.e. 0.0005 g/L) respectively
Antimony oxides can be released as a by-product of smelting lead and other metals (emissions to air, land or water), and coal-fired power plants (emissions to air and land).
Diffuse sources, and industry sources included in diffuse emissions data
Refuse incinerators, small industrial facilities involving lead casting etc, and burning of fossil fuels, e.g. for home heating (emissions to air and land).
Antimony ores occur naturally in the earth's crust. Volcanoes can release antimony oxides into the environment. Antimony is a common component of coal and petroleum.
Emissions result from vehicle exhaust.
Products such as plastics, textiles, rubber, adhesives, pigments and paper. Antimony alloys are found in solder, sheet, pipe, bearing and type metals, and castings.
Sources used in preparing this information
- Agency for Toxic Substances and Disease Registry (ATSDR), ToxFAQs, Antimony (accessed May, 1999)
- Australian and New Zealand Environment and Conservation Council (ANZECC) (1992), Australian Water Quality Guidelines for Fresh and Marine Waters.
- ChemFinder WebServer Project (1995), Antimony (accessed May, 1999)
- Cornell University, Planning Design and Construction, MSDS search page (accessed May, 1999)
- Environmental Chemicals Data and Information Network (ECDIN) query page, Antimony (accessed May, 1999)
- Environmental Writer. Antimony (Sb) Chemical Backgrounder, Antimony (accessed May, 1999)
- EPA factsheets for regulated toxic chemical, Antimony (accessed May, 1999)
- IARC: ANTIMONY TRIOXIDE AND ANTIMONY TRISULFIDE (accessed June, 1999)
- Integrated Risk Information System (IRIS) , Antimony (accessed May, 1999)
- Merian, E. (editor, 1991), Metals and Their Compounds in the Environment - Occurrence, Analysis, and Biological Relevance, VCH.
- Technical Advisory Panel (1999), Final Report to the National Environment Protection Council.
- US EPA (Environmental Protection Agency) TTNWeb (Technology Transfer Network) and US OAQPS (Office of Air Quality Planning & Standards) UATW (Unified Air Toxics Website), Antimony (accessed May, 1999)
- US EPA, Office of Water, Antimony (accessed May, 1999)
- Safe Work Australia, Workplace exposure standards for airborne contaminants, accessed June 2021.
- National Health and Medical Research Council (NHMRC), Australian Drinking Water Guidelines (2011) - Updated October 2017, accessed May 2018