Metam sodium is an

organosulfur compound Organosulfur chemistry is the study of the properties and synthesis of organosulfur compounds, which are organic compounds that contain sulfur. They are often associated with foul odors, but many of the sweetest compounds known are organosulfur der ...

with the formula . The compound is a sodium salt of a

dithiocarbamate In organic chemistry, a dithiocarbamate is a chemical compound with the general formula . It contains the functional group with the Chemical structure, structure . It is the analog of a carbamate in which both oxygen atoms are replaced by sulfur ...

. The compound exists as a colorless dihydrate, but most commonly it is encountered as an aqueous solution. It is used as a soil fumigant,

pesticide Pesticides are substances that are used to control pests. They include herbicides, insecticides, nematicides, fungicides, and many others (see table). The most common of these are herbicides, which account for approximately 50% of all p ...

herbicide Herbicides (, ), also commonly known as weed killers, are substances used to control undesired plants, also known as weeds.EPA. February 201Pesticides Industry. Sales and Usage 2006 and 2007: Market Estimates. Summary in press releasMain page f ...

, and

fungicide Fungicides are pesticides used to kill parasitic fungi or their spores. Fungi can cause serious damage in agriculture, resulting in losses of yield and quality. Fungicides are used both in agriculture and to fight fungal infections in animals, ...

. It is one of the most widely used pesticides in the United States, with approximately 60 million pounds used in 2001. Metam-sodium belongs to two HRAC groups, so it is designated Group A/C (Aus), Group A/C1 (global) and Group 1/5 (numeric).

Preparation and properties

Metam sodium is prepared by combining

methylamine Methylamine, also known as methanamine, is an organic compound with a formula of . This colorless gas is a derivative of ammonia, but with one hydrogen atom being replaced by a methyl group. It is the simplest primary amine. Methylamine is sold ...

carbon disulfide Carbon disulfide (also spelled as carbon disulphide) is an inorganic compound with the chemical formula and structure . It is also considered as the anhydride of thiocarbonic acid. It is a colorless, flammable, neurotoxic liquid that is used as ...

, and

sodium hydroxide Sodium hydroxide, also known as lye and caustic soda, is an inorganic compound with the formula . It is a white solid ionic compound consisting of sodium cations and hydroxide anions . Sodium hydroxide is a highly corrosive base (chemistry), ...

: : It also arises from the reaction of methyl isothiocyanate and sodium thiolate. Upon exposure to the environment, metam sodium decomposes to methyl isothiocyanate and other sulfur compounds.

Safety and environmental considerations

Metam sodium is nonpersistent in the environment since it decomposes rather quickly to toxic methyl isothiocyanate and

. In 1991 a tank car with 19,000 gallons of a metam sodium based pesticide spilled into

Sacramento River The Sacramento River () is the principal river of Northern California in the United States and is the largest river in California. Rising in the Klamath Mountains, the river flows south for before reaching the Sacramento–San Joaquin River D ...

above Lake Shasta. This killed all fish in a 41-mile stretch of the river. 20 years later the

rainbow trout The rainbow trout (''Oncorhynchus mykiss'') is a species of trout native to cold-water tributary, tributaries of the Pacific Ocean in North America and Asia. The steelhead (sometimes called steelhead trout) is an Fish migration#Classification, ...

population had recovered.

References

External links

* {{DEFAULTSORT:Metham Sodium Pesticides Herbicides Fungicides Dithiocarbamates Organic sodium salts Group 1 herbicides Group 5 herbicides

Preparation and properties

Safety and environmental considerations

See also

References

External links