Tin is a metal. There are four main groups of organotin compounds, depending on the number of organic groups contained: tetra-, tri-, di- and mono-organotin compounds. The organic group may be an alkyl chain or an aromatic ring. Common alkyl chains are butyl or octyl, and a common aromatic ring is phenyl. Tri-, di- and mono-organotin compounds also contain several chemical groups, which may be inorganic, e.g. chloride, or organic, e.g. carboxylate.
Tetraorganic tin compounds are mostly used as a raw material for the manufacturing of other tin-organic compounds and do not occur in chemical products.
Triorganic tin compounds function as biocidal agents and are used in wood preservatives and antifouling paints, as well as other preservatives. They have properties hazardous to health and the environment, here you can search for the substances in the Classification database. Their use is greatly restricted by various prohibitions.
Mono- and diorganic tin compounds are used as stabilisers in plastics manufacturing. They may also occur in sealants, adhesives, jointing compounds and coatings, where they function as catalysts in the binder, see brief statistics (link to brief statistics on organotin compounds). The Swedish Chemicals Agency has drawn up substance information and flow analyses for dibutyltin compounds.
How toxic the mono- and diorganic tin compounds are depends on which alkyl groups they contain. A proposal for health and environmental hazard classification of dioctyl and dibutyl tin compounds is under discussion within the EU. Available data suggest that dibutyltin compounds are more toxic than dioctyltin compounds. Both types of tin compounds may affect the immune system on repeated exposure. Dibutyltin compounds may have a corrosive or irritant effect on skin and eyes. This also suggests that dibutyltin compounds may have effects that are toxic to reproduction or mutagenic.
There are also data indicating that mono- and dibutyltin compounds and dioctyltin compounds can be classified as environmentally hazardous. Monooctyltin compounds are not readily degradable in the environment, but there is a lack of effect data to be able to make an assessment of whether they should be classified as environmentally hazardous.
Analyses by the Swedish Chemicals Agency in connection with enforcement 2008-2013. Enforcement 6/14. Swedish Chemicals Agency, 2014.
Characterisation of known endocrine disrupters to assess how current information requirements and proposed criteria identify endocrine disrupter substances. PM 15/12. Swedish Chemicals Agency, 2012.
Tennorganiska stabilisatorer i PVC (Organotin stabilisers in PVC). Report 5/00. Swedish Chemicals Agency, 2000.