For a long time the sources of nitrogen compounds was limited.

They are one of the more common groups of nitrogen compounds.

The nitrogen compounds involved are reactive, and can be transformed into one another.

Nitrogen compounds are basic building blocks in animal biology as well.

They estimated that another 20 percent consisted of organic nitrogen compounds.

In the presence of sunlight, the nitrogen compounds produce ozone.

She earned this honor for her work with asymmetric nitrogen compounds.

Targeting nitrogen compounds, with heavy emphasis on power plants, which produce about half of the region's emissions.

Nitrogen compounds were well known by the Middle Ages.

Usually aromatic nitrogen compounds or amines are used for this purpose.

Many nitrogen compounds, such as hydrogen cyanide and explosives are also highly dangerous.

There are differences in strains' abilities to metabolize various carbon and nitrogen compounds.

Activated carbon filters absorb nitrogen compounds and other toxins from the water.

Virtually all synthetic nitrogen compounds are derived from ammonia.

Others are composed of xanthine, a nitrogen compound.

An analogous process for organic nitrogen compounds is deamination.

Nitrates and organic nitrogen compounds are reduced to ammonia.

Nitrogen compound emissions from internal combustion engines are a root cause of smog.

Non-organic gardens use fertilizer which contains nitrogen compounds.

Outside their major uses as fertilizers and energy-stores, nitrogen compounds are versatile organics.

Nectar can be cheap, but pollen is generally expensive as it is relatively high in nitrogen compounds.

Nitrogen compounds are also formed from the combustion process from atmospheric nitrogen.

Heating Alcian blue produces toxic fumes of nitrogen compounds.

When it splits through the sky, it changes nitrogen gas in the air to nitrogen compounds.

But scientists now say that nitrogen compounds are a critical player in transforming life-sustaining oxygen into lung-searing ozone.