Occurrence Abundance in the Earth crust
|
N |
P |
As |
Sb |
Bi |
Abundance, by mass, % |
0.04 |
0.04 |
1.7.10-4 |
4.10-5 |
2.10-5 |
Nitrogen content (a “clark” according | an American geologist F.Clark) in the earth's crust makes up 0.04 % by mass. It occupies the 18-th place among other elements. Most of nitrogen |its| |portion| (about 4.1015 tons) is concentrated in the atmosphere, the main|main| part|portion| of which|what| (75,6 mass %) is gaseous|folds| N2 (there is 80 thousand tons of N2 above|over| 1 hectare| of Earth surface).
Of nitrogen minerals of an industrial value is only the Chilean NaNO3|importance,meaning|, Indian KNO3 and Norwegian Ca(NO3)2 saltpetres.
Nitrogen in the form of complex|complex| organic derivatives is present|login| in the composition of proteins, in the bound|coupled| state|appearance| it is contained|maintained| in petroleum (up to 1.5 % by mass.), in anthracite coal (up to 2.5 % mass).
P is very common in the earth's crust, its content being about 0.04%. P is ahead of N, S and Cl in abundance. Unlike N Phosphorus occurs in nature only in the form of compounds. The main minerals of P are:
phosphorites Ca3 (PO4)2
apatite 3Ca3(PO4)2.CaX2 (where X = F, Cl, OH).
In addition, phosphorus is present in animals and human body: a lot of phosphorus is present in the human brain, the skeleton containing up to 2 kg of Ca3(PO4)2.
As, Sb, Bi. The content of these elements in the Earth's crust is relatively low and decreases in the series As - Sb - Bi. As – 1.7.10-4%, Sb - 4.10-5%, Bi - 2.10-5%. They mostly form sulfide minerals.
The main mineral of arsenic is arsenical pyrites with approximate formula FeAsS, furthermore, orpiment As4S6, realgar As4S4 and As2S3. Antimony occurs in the free state (though very rarely) and stibnite Sb2S3.
Bismuth also found in the free state (though very rarely) and bismuthinite, Bi2S3, bismite (bismuth ocher) Bi2O3.