An electrostatic potential map of the nitrate ion. Areas colored red are lower in energy than areas coloured yellow. The oxygen atoms carry the majority of the negative charge.
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The structure and bonding of the nitrate ion. The N-O bonds are intermediate in length and strength between a single bond and a double bond.
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In inorganic chemistry, a nitrate is a salt of nitric acid with an ion composed of one nitrogen and three oxygen atoms (NO3-). In organic chemistry the esters of nitric acid and various alcohols are called nitrates.
Chemical properties
The nitrate ion is a polyatomic ion with the empirical formula NO3- and a molecular mass of 62.0049. It is the conjugate base of nitric acid, consisting of one central nitrogen atom surrounded by bcanonical structures of the nitrate ion are shown resonating below:
Almost all inorganic nitrate salts are soluble in water at standard temperature and pressure.
In organic chemistry a nitrate is a functional group with general chemical formula RONO2 where R stands for any organic residue. They are the esters of nitric acid and alcohols formed by nitroxylation. Examples are methyl nitrate formed by reaction of methanol and nitric acid,[1] the nitrate of tartaric acid,[2] and the inappropriately named nitroglycerin.
Related materials
Nitrates should not be confused with nitrites, (NO2-) the salts of nitrous acid. Organic compounds containing the nitro functional group (which has the same formula and structure as the nitrate ion save that one of the O- atoms is replaced by the R group) are known as nitro compounds.
Human toxicity
High levels of nitrates, most often through occupational exposure in adults, are toxic to humans. Nitrates oxidize the iron atoms in hemoglobin from Ferrous Iron (2+) to Ferric Iron (3+), rendering it unable to carry oxygen. This condition is called methemoglobinemia and can lead to a lack of oxygen in tissues. Methemoglobinemia is treated with methylene blue.
Infants, in particular, are especially sensitive to methemoglobinemia as a result of nitrate exposure. This is most often caused by high levels of nitrates in drinking water.
Marine toxicity
The state of knowledge regarding the treatment of patients potentially exposed to hazardous substances in the environment is constantly evolving and is often uncertain. In this educational monograph, ATSDR has made diligent effort to ensure the accuracy and currency of the information presented, but makes no claim that the document comprehensively addresses all possible situations related to this substance. This monograph is intended as an educational resource for physicians and other health professionals in assessing the condition and managing the treatment of patients potentially exposed to hazardous substances. It is not, however, a substitute for the professional judgment of a health care provider. The document must be interpreted in light of specific information regarding the patient and in conjunction with other sources of authority.
Use of trade names and commercial sources is for identification only and does not imply endorsement by the Agency for Toxic Substances and Disease Registry or the U.S. Department of Health and Human Services.
See also
External links
References
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