NITROGEN

Introduction

Atomic Number: 7
Group: 15 or V A
Atomic Weight: 14.0067
Period: 2
CAS Number: 7727-37-9

Classification

Chalcogen
Halogen
Noble Gas
Lanthanoid
Actinoid
Rare Earth Element
Platinum Group Metal
Transuranium
No Stable Isotopes
Solid
Liquid
Gas
Solid (Predicted)

Description • Uses/Function

Discovered by Daniel Rutherford in 1772, but Scheele, Cavendish, Priestley,and others about the same time studied “burnt or dephlogisticated air,” as air without oxygen was then called. Nitrogen makes up 78% of the air, byvolume. The atmosphere of Mars, by comparison, is 2.6% nitrogen. The estimated amount of this element in our atmosphere is more than 4000 trilliontons. From this inexhaustible source it can be obtained by liquefaction and fractional distillation. Nitrogen molecules give the orange-red, blue-green,blue-violet, and deep violet shades to the aurora.The element is so inert that Lavoisier named it azote, meaning without life, yet its compounds are soactive as to be most important in foods, poisons, fertilizers, and explosives. Nitrogen can be also easily prepared by heating a water solution ofammonium nitrite. Nitrogen, as a gas, is colorless, odorless, and a generally inert element. As a liquid it is also colorless and odorless, and is similarin appearance to water. Two allotropic forms of solid nitrogen exist, with the transition from the alpha to the beta form taking place at –237°C. When nitrogenis heated, it combines directly with magnesium, lithium, or calcium; when mixed with oxygen and subjected to electric sparks, it forms first nitric oxide(NO) and then the dioxide (NO2); when heated under pressure with a catalyst with hydrogen, ammonia is formed (Haber process). The ammonia thusformed is of the utmost importance as it is used in fertilizers, and it can be oxidized to nitric acid (Ostwald process). The ammonia industryis the largestconsumer of nitrogen. Large amounts of gas are also used by the electronics industry, which uses the gas as a blanketing medium during productionof such components as transistors, diodes, etc. Large quantities of nitrogen are used in annealing stainless steel and other steel mill products. The drugindustry also uses large quantities. Nitrogen is used as a refrigerant both for the immersion freezing of food products and for transportation of foods.Liquid nitrogen is also used in missile work as a purge for components, insulators for space chambers, etc., and by the oil industry to build up greatpressures in wells to force crude oil upward. Sodium and potassium nitrates are formed by the decomposition of organic matter with compounds ofthe metals present. In certain dry areas of the world these saltpeters are found in quantity. Ammonia, nitric acid, the nitrates, the five oxides (N2O, NO,N2O3, NO2, and N2O5), TNT, the cyanides, etc. are but a few of the important compounds. Nitrogen gas prices vary from 2¢ to $2.75 per 100 ft3 (2.83cu. meters), depending on purity, etc. Production of elemental nitrogen in the U.S. is more than 9 million short tons per year. Natural nitrogen containstwo isotopes, 14N and 15N. Ten other isotopes are known. 1

• "very useful as a medium for experiments involving substances that react with oxygen or water," 2
• "Although N2 molecules are realtively unreactive, nature provides mechanisms by which N atoms are incorporated into proteins, nucleic acids, and other nitrogenous compounds. The nitrogen cycle is the complex series of reactions by which nitrogen is slowly but continually recycled in the atmosphere (our nitrogen reservoir), lithosphere (earth), and hydrosphere (water)." 3
• "is essential for the growth of living things, and nitrogen is therefore separated from air on a large scale to make fertilizers. Other major uses are in the manufacture of explosives and propellants, and in the provision of an inert atmosphere for chemical processing." 4
• "2nd most produced chemical in the United States in 1995 - 30.6 megatonnes." 5
• "2nd most produced chemical in the United States - 47.32 billion pounds" 6

Physical Properties

Density:7  1.145 g/L

* - at 1 atm

Electron Configuration

Electron Configuration: [He] 2s2 2p3
Block: p
Highest Occupied Energy Level: 2
Valence Electrons: 5

Quantum Numbers:

n = 2
ℓ = 1
m = 1
ms = +½

Bonding

Electronegativity (Pauling scale):8 3.04
Electropositivity (Pauling scale): 0.96
Electron Affinity:9 not stable eV
Oxidation States: -3

Ionization Potential   eV 10  kJ/mol  
1 14.53414    1402.3
2 29.6013    2856.1
Ionization Potential   eV 10  kJ/mol  
3 47.44924    4578.2
4 77.4735    7475.1
Ionization Potential   eV 10  kJ/mol  
5 97.8902    9445.0
6 552.0718    53266.8
7 667.046    64360.1

Thermochemistry

Specific Heat: 1.040 J/g°C 11 = 14.567 J/mol°C = 0.249 cal/g°C = 3.482 cal/mol°C
Thermal Conductivity: 0.02598 (W/m)/K, 27°C 12
Heat of Fusion: 0.3604 kJ/mol 13 = 25.7 J/g
Heat of Vaporization: 2.7928 kJ/mol 14 = 199.4 J/g
State of Matter Enthalpy of Formation (ΔHf°)15 Entropy (S°)15 Gibbs Free Energy (ΔGf°)15
(kcal/mol) (kJ/mol) (cal/K) (J/K) (kcal/mol) (kJ/mol)
(g) 0 0 45.77 191.50168 0 0

Isotopes

Nuclide Mass 16 Half-Life 16 Nuclear Spin 16 Binding Energy
10N 10.04165(43) 200(140)E-24 s [2.3(16) MeV] (2-) 37.05 MeV
11N 11.02609(5) 590(210)E-24 s [1.58(+75-52) MeV] 1/2+ 59.09 MeV
12N 12.0186132(11) 11.000(16) ms 1+ 74.61 MeV
13N 13.00573861(29) 9.965(4) min 1/2- 94.79 MeV
14N 14.0030740048(6) STABLE 1+ 104.73 MeV
15N 15.0001088982(7) STABLE 1/2- 115.59 MeV
16N 16.0061017(28) 7.13(2) s 2- 118.08 MeV
17N 17.008450(16) 4.173(4) s 1/2- 124.28 MeV
18N 18.014079(20) 622(9) ms 1- 126.77 MeV
19N 19.017029(18) 271(8) ms (1/2)- 132.04 MeV
20N 20.02337(6) 130(7) ms 134.53 MeV
21N 21.02711(10) 87(6) ms 1/2-# 138.87 MeV
22N 22.03439(21) 13.9(14) ms 140.42 MeV
23N 23.04122(32)# 14.5(24) ms [14.1(+12-15) ms] 1/2-# 141.97 MeV
24N 24.05104(43)# <52 ns 140.73 MeV
25N 25.06066(54)# <260 ns 1/2-# 140.42 MeV
Values marked # are not purely derived from experimental data, but at least partly from systematic trends. Spins with weak assignment arguments are enclosed in parentheses. 16

Reactions

Abundance

Earth - Source Compounds: uncombined 23
Earth - Seawater: 50 mg/L 24
Earth -  Crust:  19 mg/kg = 0.0019% 24
Earth -  Lithosphere:  0.002% 25
Earth -  Atmosphere:  75.5% 25
Earth -  Total:  4.1 ppm 26
Mercury -  Total:  0.046 ppm 26
Venus -  Total:  4.3 ppm 26
Chondrites - Total: 90 (relative to 106 atoms of Si) 27
Human Body - Total: 2.6% 28

Compounds

Safety Information


Material Safety Data Sheet - ACI Alloys, Inc.

For More Information

External Links:

Magazines:
(1) Catling, David C. and Zahnle, Kevin J. The Planetary Air Leak. Scientific American, May 2009, pp 36-43.
(2) Townsend, Alan R. and Howarth, Robert W. Fixing the Global Nitrogen Problem. Scientific American, February 2010, pp 64-71.

Sources

(1) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 4:21.
(2) - Zumdahl, Steven S. Chemistry, 4th ed.; Houghton Mifflin: Boston, 1997; pp 899-900.
(3) - Whitten, Kenneth W., Davis, Raymond E., and Peck, M. Larry. General Chemistry 6th ed.; Saunders College Publishing: Orlando, FL, 2000; p 959.
(4) - Swaddle, T.W. Inorganic Chemistry; Academic Press: San Diego, 1997; p 6.
(5) - Chem. Eng. News, 1995, 73 (26), p 39
(6) - Reisch, Mark S.; Top 50 Chemicals Production Turned Back Up in 1987. Chemical & Engineering News, April 11, 1988, pp 30-33.
(7) - Lide, David R. CRC Handbook of Chemistry and Physics, 84th ed.; CRC Press: Boca Raton, FL, 2002; p 4:39-4:96.
(8) - Lide, David R. CRC Handbook of Chemistry and Physics, 84th ed.; CRC Press: Boca Raton, FL, 2002; p 10:147-10:148.
(9) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 10:178 - 10:180.
(10) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 4:133.
(11) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; pp 6:193, 12:219-220.
(12) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; pp 6:123-6:137.
(13) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; pp 6:107-6:122.
(14) - Dean, John A. Lange's Handbook of Chemistry, 12th ed.; McGraw-Hill Book Company: New York, NY, 1979; p 9:4-9:94.
(15) - Atomic Mass Data Center. http://amdc.in2p3.fr/web/nubase_en.html (accessed July 14, 2009).
(16) - T < 1358.27773574524
(17) - T > 3868.32689280092
(18) - T > 1168.86288285073
(19) - T > -1195.09638609124
(20) - T < 5189.88122782662
(21) - T > -9677.38977611371
(22) - Silberberg, Martin S. Chemistry: The Molecular Nature of Matter and Change, 4th ed.; McGraw-Hill Higher Education: Boston, MA, 2006, p 965.
(23) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 14:17.
(24) - Silberberg, Martin S. Chemistry: The Molecular Nature of Matter and Change, 4th ed.; McGraw-Hill Higher Education: Boston, MA, 2006, p 964.
(25) - Morgan, John W. and Anders, Edward, Proc. Natl. Acad. Sci. USA 77, 6973-6977 (1980)
(26) - Brownlow, Arthur. Geochemistry; Prentice-Hall, Inc.: Englewood Cliffs, NJ, 1979, pp 15-16.
(27) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 7:17.