Atomic Number: 11
Group: 1 or I A
Atomic Weight: 22.98977
Period: 3
CAS Number: 7440-23-5


Noble Gas

Platinum Group Metal
No Stable Isotopes
Solid (Predicted)


Long recognized in compounds, sodium was first isolated by Davy in 1807 by electrolysis of caustic soda. Sodium is present in fair abundance in the sun and stars. The D lines of sodium are among the most prominent in the solar spectrum. Sodium is the sixth most abundant element on earth, comprising about 2.6% of the earth’s crust; it is the most abundant of the alkali group of metals of which it is a member. The most common compound is sodium chloride, but it occurs in many other minerals, such as soda niter, cryolite, amphibole, zeolite, sodalite,etc. It is a very reactive element and is never found free in nature. It is now obtained commercially by the electrolysis of absolutely dry fused sodium chloride. This method is much cheaper than that of electrolyzing sodium hydroxide, as was used several years ago. Sodium is a soft, bright, silvery metal which floats on water, decomposing it with the evolution of hydrogen and the formation of the hydroxide. It may or may not ignite spontaneously on water, depending on the amount of oxide and metal exposed to the water. It normally does not ignite in air at temperatures below 115°C. Sodium should be handled with respect, as it can be dangerous when improperly handled. Metallic sodium is vital in the manufacture of sodamide and esters, and in the preparation of organic compounds. The metal may be used to improve the structure of certain alloys, to descale metal, to purify molten metals, and as a heat transfer agent. An alloy of sodium with potassium, NaK, is also an important heat transfer agent. Sodium compounds are important to the paper, glass, soap, textile, petroleum, chemical, and metal industries. Soap is generally a sodium salt of certain fatty acids. The importance of common salt to animal nutrition has been recognized since prehistoric times. Among the many compounds that are of the greatest industrial importance are common salt (NaCl), soda ash (Na2CO3), baking soda (NaHCO3), caustic soda (NaOH), Chile saltpeter (NaNO3), di- and tri-sodium phosphates, sodium thiosulfate (hypo, Na2S2O3 · 5H2O), and borax (Na2B4O7 · 10H2O). Seventeen isotopes of sodium are recognized. Metallic sodium is priced at about $250/kg (99.95%). On a volume basis, it is the cheapest of all metals. Sodium metal should be handled with great care. It should be kept in an inert atmosphere and contact with water and other substances with which sodium reacts should be avoided. 1


•is still important in the manufacture of many chemicals, including pharmaceuticals and dyes such as indigo." 2
•Sodium is used in making sodium peroxide, sodium cyanide, and in the manufacture of many complex compounds used as drugs and dyes. Its activity makes it valuable for the study of typical chemical actions. The alloy of sodium with mercury (sodium amalgam) is an important reducing agent. A sodium-lead alloy is used in making ethyl gasoline. Another use for sodium is in sodium vapor lamps used to light our highways with the bright yellow light which is characteristic of sodium. The sodium is vaporized and heated to incandescence by the electric current." 3
•The metal itself is used as a reducing agent in the manufacture of drugs and dyes and in the metallurgy of such metals as titanium and zirconium...Highway lamps often incorporate Na arcs, which produce a bright yellow glow." 4
Sodium chloride, from which sodium is extracted by electrolysis, can be obtained in a fairly pure form by the evaporation of seawater in large ponds." 5

Physical Properties

Melting Point:6*  97.80 °C = 370.95 K = 208.04 °F
Boiling Point:6* 883 °C = 1156.15 K = 1621.4 °F
Sublimation Point:6 
Triple Point:6 
Critical Point:6 2300 °C = 2573.15 K = 4172 °F 6
Density:7  0.97 g/cm3

* - at 1 atm

Electron Configuration

Electron Configuration: [Ne] 3s1
Block: s
Highest Occupied Energy Level: 3
Valence Electrons: 1

Quantum Numbers:

n = 3
ℓ = 0
m = 0
ms = +½


Electronegativity (Pauling scale):8 0.93
Electropositivity (Pauling scale): 3.07
Electron Affinity:9 0.547926 eV
Oxidation States: +1
Work Function:10 2.70 eV = 4.3254E-19 J

Ionization Potential   eV 11  kJ/mol  
1 5.13908    495.8
2 47.2864    4562.4
3 71.62    6910.3
Ionization Potential   eV 11  kJ/mol  
3 71.62    6910.3
4 98.91    9543.4
5 138.4    13353.6
6 172.18    16612.8
7 208.5    20117.2
Ionization Potential   eV 11  kJ/mol  
8 264.25    25496.2
9 299.864    28932.5
10 1465.121    141362.7
11 1648.702    159075.5


Specific Heat: 1.228 J/g°C 12 = 28.231 J/mol°C = 0.293 cal/g°C = 6.747 cal/mol°C
Thermal Conductivity: 141 (W/m)/K, 27ºC 13
Heat of Fusion: 2.598 kJ/mol 14 = 113.0 J/g
Heat of Vaporization: 96.96 kJ/mol 15 = 4217.5 J/g
State of Matter Enthalpy of Formation (ΔHf°)16 Entropy (S°)16 Gibbs Free Energy (ΔGf°)16
(kcal/mol) (kJ/mol) (cal/K) (J/K) (kcal/mol) (kJ/mol)
(s) 0 0 12.30 51.4632 0 0
(ℓ) 0.575 2.4058 13.83 57.86472 0.119 0.497896
(g) 25.75 107.738 36.71 153.59464 18.48 77.32032


Nuclide Mass 17 Half-Life 17 Nuclear Spin 17 Binding Energy
18Na 18.02597(5) 1.3(4)E-21 s (1-)# 109.78 MeV
19Na 19.013877(13) <40 ns (5/2+)# 129.04 MeV
20Na 20.007351(7) 447.9(23) ms 2+ 142.71 MeV
21Na 20.9976552(8) 22.49(4) s 3/2+ 160.11 MeV
22Na 21.9944364(4) 2.6027(10) yr 3+ 170.98 MeV
23Na 22.9897692809(29) STABLE 3/2+ 183.72 MeV
24Na 23.99096278(8) 14.9590(12) h 4+ 190.86 MeV
25Na 24.9899540(13) 59.1(6) s 5/2+ 199.87 MeV
26Na 25.992633(6) 1.077(5) s 3+ 205.16 MeV
27Na 26.994077(4) 301(6) ms 5/2+ 211.37 MeV
28Na 27.998938(14) 30.5(4) ms 1+ 215.72 MeV
29Na 29.002861(14) 44.9(12) ms 3/2(+#) 220.08 MeV
30Na 30.008976(27) 48.4(17) ms 2+ 222.57 MeV
31Na 31.01359(23) 17.0(4) ms (3/2+) 225.99 MeV
32Na 32.02047(38) 12.9(7) ms (3-,4-) 227.54 MeV
33Na 33.02672(94) 8.2(2) ms 3/2+# 230.03 MeV
34Na 34.03517(96)# 5.5(10) ms 1+ 229.73 MeV
35Na 35.04249(102)# 1.5(5) ms 3/2+# 231.28 MeV
36Na 36.05148(102)# <260 ns 230.98 MeV
37Na 37.05934(103)# 1# ms [>1.5 µs] 3/2+# 231.60 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. 17


2 18
2 19
1 20
2 21
1 22


Earth - Source Compounds: halide salts or brines 23
Earth - Seawater: 10800 mg/L 24
Earth -  Crust:  0.000236 mg/kg = 0.0000000236% 24
Earth -  Mantle:  0.8% 25
Earth -  Lithosphere:  2.27% 26
Earth -  Hydrosphere:  1.1% 26
Earth -  Total:  1250 ppm 27
Mercury -  Total:  200 ppm 27
Venus -  Total:  1390 ppm 27
Chondrites - Total: 4.6×104 (relative to 106 atoms of Si) 28
Human Body - Total: 0.14% 29


sodium 1-heptyl sulfate
sodium 1-propene-3-sulfonate
sodium 1-undecanesulfonate; 1-hendecanesulfonic acid sodium salt
sodium 2,1-diazonaphthol-5-sulfonate hydrate
sodium 2-ethylhexyl sulfate
sodium 2-mercaptobenzothiazole
sodium abietate
sodium acetate trihydrate
sodium acetate; sodium ethanoate
sodium acrylate
sodium acrylate-acrylamide copolymer
sodium adipate
sodium alginate
sodium aluminate; sodium aluminium oxide
sodium aluminium hydride
sodium aluminosilicate
sodium amide
sodium ammonium phosphate
sodium antimonate
sodium antimonide
sodium arsenate dodecahydrate
sodium arsenate heptahydrate
sodium arsenite
sodium ascorbate
sodium aurothiomalate
sodium azide
sodium benzoate; benzoate of soda
sodium benzosulfonate
sodium bicarbonate
sodium bifluoride
sodium biphenyl reagent
sodium bismuthate
sodium bisulfate monohydrate; sodium hydrogen sulfate monohydrate
sodium bisulfate(sodium hydrogen sulfate)
sodium bisulfide
sodium bisulfite
sodium bitartrate monohydrate
sodium borofluoride
sodium borohydride
sodium borosilicate
sodium bromate
sodium bromide
sodium butyrate
sodium caproamphoacetate
sodium caprylate
sodium carbonate
sodium carbonate monohydrate
sodium chlorate
sodium chloride
sodium chlorite
sodium chromate
sodium chromate tetrahydrate
sodium citrate
sodium citrate dihydrate
sodium citrate pentahydrate
sodium cobaltinitrite; sodium hexanitritocobaltate (III)
sodium cocoyl isethionate
sodium cyanate
sodium cyanide
sodium cyanoborohydride
sodium decylbenzenesulfonate
sodium dehydroacetate
sodium desoxycholate
sodium deuteroxide solution
sodium diacetate
sodium dichloroisocyanurate dihydrate
sodium dichloroisocyanurate; sodium 3,5-dichloro-2,4,6-trioxo-1,3,5-triazinan-1-ide*
sodium dichromate
sodium dichromate dihydrate
sodium diethylbarbiturate
sodium diethyldithiocarbamate
sodium diethyldithiocarbamate trihydrate
sodium dihydrogen phosphate dihydrate
sodium dimethylarsinate
sodium dimethyldithiocarbamate
sodium dimethylglyoximate octahydrate
sodium dinitro-o-cresolate
sodium diphenylamine-4-sulphonate
sodium dithionate
sodium dithionite
sodium dodecylbenzene sulfonate
sodium ethenesulfonate
sodium ethoxide
sodium ferricyanide
sodium ferrocyanide
sodium fluoride
sodium fluoroacetate
sodium fluorophosphate; sodium monofluorophosphate
sodium fluorosilicate
sodium formaldehydesulfoxylate; rongalite; sodium formaldehydesulfoxylate
sodium formate
sodium gluconate
sodium glutamate
sodium glycerophosphate
sodium glycinate
sodium hexacyanoferrate(II) 10-hydrate
sodium hexafluoroaluminate
sodium hexafluoroarsenate(V)
sodium hexafluorophosphate
sodium hexametaphosphate
sodium hydride
sodium hydromethylglycinate
sodium hydrosulfide hydrate
sodium hydroxide
sodium hypochlorite
sodium hypophosphite
sodium hypophosphite monohydrate
sodium iodate
sodium iodide
sodium iodide dihydrate
sodium lactate
sodium lauryl ether sulfate
sodium lauryl sulfate(sodium dodecyl sulfate)
sodium maleate hydrate
sodium malonate
sodium metabisulfite
sodium metaborate hydrate
sodium metaperiodate; sodium periodate
sodium metasilicate nonahydrate
sodium metatitanate
sodium metavanadate
sodium methoxide; sodium methylate
sodium methylene naphthalene sulfonate
sodium molybdate
sodium molybdate dihydrate*
sodium monochloroacetate
sodium monoxide
sodium naphthalene-2-sulfonate
sodium naphthalenesulfonate
sodium n-decyl sulfate
sodium n-hexadecyl sulphate
sodium niobate
sodium nitrate
sodium nitrilotriacetate
sodium nitrite
sodium nitroferricyanide dihydrate
sodium n-nonyl sulfate
sodium n-octyl sulphate
sodium n-tetradecyl sulphate
sodium oleate
sodium orthosilicate
sodium oxalate
sodium oxide
sodium p-aminosalicylate
sodium pentachlorophenate
sodium perborate tetrahydrate
sodium perchlorate
sodium permanganate
sodium peroxide
sodium perrhenate
sodium persulfate
sodium phenolate
sodium phenylacetate
sodium phosphate
sodium phosphate dibasic dihydrate
sodium phosphate dibasic(sodium hydrogen phosphate)
sodium phosphate dodecahydrate; trisodium phosphate dodecahydrate
sodium phosphite dibasic pentahydrate
sodium POE(10) lauryl ether phosphate
sodium polyacrylate
sodium polymethacrylate
sodium polyphosphate
sodium propionate
sodium p-styrenesulfonate
sodium pyrophosphate
sodium ricinoleate
sodium salicylate
sodium selenate
sodium selenide
sodium selenite
sodium selenite pentahydrate
sodium silicate
sodium silicate
sodium silicoaluminate
sodium stannate
sodium stannate trihydrate
sodium stearate
sodium succinate
sodium sulfate
sodium sulfate decahydrate
sodium sulfide
sodium sulfide nonahydrate
sodium sulfide pentahydrate
sodium sulfite
sodium superoxide
sodium tartrate dihydrate
sodium tartrate; 2.3-dihydroxy sodium succinate
sodium telluride
sodium tellurite
sodium tetraborate decahydrate; borax
sodium tetracholoraluminate
sodium tetrafluoroaluminate
sodium tetraphenylborate
sodium thioantimonide
sodium thiocyanate; sodium rhodanide; sodium sulfocyanate
sodium thiosulfate
sodium thiosulfate pentahydrate
sodium tosylate
sodium tripolyphosphate
sodium tungstate
sodium tungstate dihydrate
sodium vanadate
sodium xylenesulfonate
sodium-mercury amalgam

Safety Information

Material Safety Data Sheet - ACI Alloys, Inc.


Afrikaans:   Natrium
Albanian:   Natrium
Armenian:   Նատրիում
Arabic:   صوديوم
Aromanian:   Natriumu
Basque:   Sodioa
Bosnian:   Natrij
Breton:   Sodiom or Natriom
Bulgarian:   Натрий
Belarusian:   Натрый
Catalan :   Sodi
Chinese :   钠
Cornish :   Sodyum
Croatian :   Natrij
Czech :   Sodík
Danish:   Natrium
Dutch:   Natrium
Esperanto:   Natrio
Estonian:   Naatrium
Faroese:   Natrium
Finnish:   Natrium
French:   Sodium
Friulan: Sodi
Frisian:   Natrium
Galician:   Sodio
Georgian:   ნატრიუმი
German:   Natrium
Greek:   Νατριο
Hebrew:   נתרן
Hungarian:   Nátrium
Icelandic:   Natur or Natrín
Irish Gaelic:   Sóidiam
Italian:   Sodio
Japanese:   ナトリウム
Kashubian:   Natrijô
Kazakh:   Натрий
Korean:   나트륨, 소듐
Latvian:   Natrijs
Lithuanian:   Natris
Luxembourgish:   Natrium
Macedonian:   Натриум
Malay:   Natrium
Maltese :   Sodjum
Manx Gaelic:   Sodjum
Moksha:   Натри
Mongolian:   Натри
Norwegian:   Natrium
Occitan:   Sòdi
Ossetian:   Натрий
Polish:   Sód
Portuguese:   Sódio
Russian:   Натрий
Scottish Gaelic:   Sòidiam
Serbian:   Натриjум
Slovak:   Sodík
Spanish:   Sodio
Sudovian:   Natrijan
Swahili:   Natiri
Swedish:   Natrium
Tajik:   Natri'
Thai:   โซเดียม
Turkish:   Sodyum
Ukranian:   Натрій
Uzbek:   Натрий
Vietnamese:   Natri
Welsh:   Sodiwm

For More Information

External Links:


(1) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 4:29.
(2) - Ebbing, Darrell D. General Chemistry 3rd ed.; Houghton Mifflin Company: Boston, MA, 1990; p 58.
(3) - Brownlee, Raymond B., Fuller, Robert W., and Whitsit, Jesse E. Elements of Chemistry; Allyn and Bacon: Boston, Massachusetts, 1959; p 180.
(4) - Whitten, Kenneth W., Davis, Raymond E., and Peck, M. Larry. General Chemistry 6th ed.; Saunders College Publishing: Orlando, FL, 2000; p 924.
(5) - Brady, James E. and Senese, Fred. Chemistry: Matter and Changes, 4th ed.; John Wiley and Sons: Hoboken, New Jersey, 2004; p 1012.
(6) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 4:132.
(7) - Lide, David R. CRC Handbook of Chemistry and Physics, 84th ed.; CRC Press: Boca Raton, FL, 2002; p 4:39-4:96.
(8) - Dean, John A. Lange's Handbook of Chemistry, 11th ed.; McGraw-Hill Book Company: New York, NY, 1973; p 4:8-4:149.
(9) - Lide, David R. CRC Handbook of Chemistry and Physics, 84th ed.; CRC Press: Boca Raton, FL, 2002; p 10:147-10:148.
(10) - Speight, James. Lange's Handbook of Chemistry, 16th ed.; McGraw-Hill Professional: Boston, MA, 2004; p 1:132.
(11) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 10:178 - 10:180.
(12) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 4:133.
(13) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; pp 6:193, 12:219-220.
(14) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; pp 6:123-6:137.
(15) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; pp 6:107-6:122.
(16) - Dean, John A. Lange's Handbook of Chemistry, 12th ed.; McGraw-Hill Book Company: New York, NY, 1979; p 9:4-9:94.
(17) - Atomic Mass Data Center. (accessed July 14, 2009).
(18) - 2
(19) - 2
(20) - 1
(21) - 2
(22) - 8
(23) - Silberberg, Martin S. Chemistry: The Molecular Nature of Matter and Change, 4th ed.; McGraw-Hill Higher Education: Boston, MA, 2006, p 965.
(24) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 14:17.
(25) - Silberberg, Martin S. Chemistry: The Molecular Nature of Matter and Change, 4th ed.; McGraw-Hill Higher Education: Boston, MA, 2006, p 962.
(26) - Silberberg, Martin S. Chemistry: The Molecular Nature of Matter and Change, 4th ed.; McGraw-Hill Higher Education: Boston, MA, 2006, p 964.
(27) - Morgan, John W. and Anders, Edward, Proc. Natl. Acad. Sci. USA 77, 6973-6977 (1980)
(28) - Brownlow, Arthur. Geochemistry; Prentice-Hall, Inc.: Englewood Cliffs, NJ, 1979, pp 15-16.
(29) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 7:17.