INDIUM

Introduction

Atomic Number: 49
Group: 13 or III A
Atomic Weight: 114.818
Period: 5
CAS Number: 7440-74-6

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 Reich and Richter, who later isolated the metal. Indium is most frequently associated with zinc materials, and it is from thesethat most commercial indium is now obtained; however, it is also found in iron, lead, and copper ores. Until 1924, a gram or so constituted the world’ssupply of this element in isolated form. It is probably about as abundant as silver. About 4 million troy ounces of indium are now produced annuallyin the Free World. Canada is presently producing more than 1,000,000 troy ounces annually. The present cost of indium is about $2 to $10/g, dependingon quantity and purity. It is available in ultrapure form. Indium is a very soft, silvery-white metal with a brilliant luster. The pure metal gives a highpitched“cry” when bent. It wets glass, as does gallium. It has found application in making low-melting alloys; an alloy of 24% indium-76% galliumis liquid at room temperature. It is used in making bearing alloys, germanium transistors, rectifiers, thermistors, and photoconductors. It can be platedonto metal and evaporated onto glass, forming a mirror as good as that made with silver but with more resistance to atmospheric corrosion. There isevidence that indium has a low order of toxicity; however, care should be taken until further information is available. Sixty seven isotopes and isomersare now recognized (more than any other element). Natural indium contains two isotopes. One is stable. The other, 115In, comprising 95.71% of naturalindium is slightly radioactive with a very long half-life. 1

• "used in some alloys with silver and lead to make good heat conductors. Most indium is used in electronics." 2

Physical Properties

Melting Point:3*  156.60 °C = 429.75 K = 313.88 °F
Boiling Point:3* 2072 °C = 2345.15 K = 3761.6 °F
Sublimation Point:3 
Triple Point:3 
Critical Point:3 
Density:4  5.7747 g/cm3

* - at 1 atm

Electron Configuration

Electron Configuration: [Kr] 5s2 4d10 5p1
Block: p
Highest Occupied Energy Level: 5
Valence Electrons: 3

Quantum Numbers:

n = 5
ℓ = 1
m = -1
ms = +½

Bonding

Electronegativity (Pauling scale):5 1.78
Electropositivity (Pauling scale): 2.22
Electron Affinity:6 0.3 eV
Oxidation States: +3
Work Function:7 4.08 eV = 6.53616E-19 J

Ionization Potential   eV 8  kJ/mol  
1 5.78636    558.3
Ionization Potential   eV 8  kJ/mol  
2 18.8698    1820.7
Ionization Potential   eV 8  kJ/mol  
3 28.03    2704.5
4 54    5210.2

Thermochemistry

Specific Heat: 0.233 J/g°C 9 = 26.753 J/mol°C = 0.056 cal/g°C = 6.394 cal/mol°C
Thermal Conductivity: 81.6 (W/m)/K, 27°C 10
Heat of Fusion: 3.263 kJ/mol 11 = 28.4 J/g
Heat of Vaporization: 231.5 kJ/mol 12 = 2016.2 J/g
State of Matter Enthalpy of Formation (ΔHf°)13 Entropy (S°)13 Gibbs Free Energy (ΔGf°)13
(kcal/mol) (kJ/mol) (cal/K) (J/K) (kcal/mol) (kJ/mol)
(s) 0 0 13.82 57.82288 0 0
(g) 58.15 243.2996 41.51 173.67784 49.89 208.73976

Isotopes

Nuclide Mass 14 Half-Life 14 Nuclear Spin 14 Binding Energy
100In 99.93111(27) 5.9(2) s (6,7)+ 833.07 MeV
101In 100.92634(32)# 15.1(3) s 9/2+# 851.39 MeV
102In 101.92409(12) 23.3(1) s (6+) 859.46 MeV
103In 102.919914(27) 60(1) s 9/2+# 876.84 MeV
104In 103.91830(9) 1.80(3) min 5,6(+) 884.92 MeV
105In 104.914674(19) 5.07(7) min 9/2+ 892.99 MeV
106In 105.913465(13) 6.2(1) min 7+ 901.06 MeV
107In 106.910295(12) 32.4(3) min 9/2+ 909.13 MeV
108In 107.909698(10) 58.0(12) min 7+ 926.52 MeV
109In 108.907151(6) 4.2(1) h 9/2+ 934.59 MeV
110In 109.907165(13) 4.9(1) h 7+ 942.66 MeV
111In 110.905103(5) 2.8047(5) d 9/2+ 950.73 MeV
112In 111.905532(6) 14.97(10) min 1+ 958.80 MeV
113In 112.904058(3) STABLE 9/2+ 966.87 MeV
114In 113.904914(3) 71.9(1) s 1+ 974.94 MeV
115In 114.903878(5) 4.41(25)E+14 a 9/2+ 983.01 MeV
116In 115.905260(5) 14.10(3) s 1+ 991.09 MeV
117In 116.904514(6) 43.2(3) min 9/2+ 999.16 MeV
118In 117.906354(9) 5.0(5) s 1+ 1,007.23 MeV
119In 118.905845(8) 2.4(1) min 9/2+ 1,015.30 MeV
120In 119.90796(4) 3.08(8) s 1+ 1,023.37 MeV
121In 120.907846(29) 23.1(6) s 9/2+ 1,031.44 MeV
122In 121.91028(5) 1.5(3) s 1+ 1,030.20 MeV
123In 122.910438(26) 6.17(5) s (9/2)+ 1,038.27 MeV
124In 123.91318(5) 3.11(10) s 3+ 1,046.34 MeV
125In 124.91360(3) 2.36(4) s 9/2+ 1,054.41 MeV
126In 125.91646(4) 1.53(1) s 3(+#) 1,062.48 MeV
127In 126.91735(4) 1.09(1) s 9/2(+) 1,070.56 MeV
128In 127.92017(5) 0.84(6) s (3)+ 1,069.31 MeV
129In 128.92170(5) 611(4) ms 9/2+# 1,077.38 MeV
130In 129.92497(4) 0.29(2) s 1(-) 1,085.45 MeV
131In 130.92685(3) 0.28(3) s (9/2+) 1,093.53 MeV
132In 131.93299(7) 206(4) ms (7-) 1,092.28 MeV
133In 132.93781(32)# 165(3) ms (9/2+) 1,100.35 MeV
134In 133.94415(43)# 140(4) ms 1,099.11 MeV
135In 134.94933(54)# 92(10) ms 9/2+# 1,107.18 MeV
97In 96.94954(64)# 5# ms 9/2+# 792.09 MeV
98In 97.94214(21)# 45(23) ms [32(+32-11) ms] 0+# 806.68 MeV
99In 98.93422(43)# 3.1(8) s [3.0(+8-7) s] 9/2+# 822.20 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. 14

Abundance

Earth - Source Compounds: sulfides 15
Earth - Seawater: 0.002 mg/L 16
Earth -  Crust:  0.25 mg/kg = 0.000025% 16
Earth -  Total:  2.14 ppb 17
Mercury -  Total:  0.024 ppb 17
Venus -  Total:  2.24 ppb 17
Chondrites - Total: 0.001 (relative to 106 atoms of Si) 18

Compounds

Safety Information


Material Safety Data Sheet - ACI Alloys, Inc.

For More Information

External Links:

Magazines:
(1) Moyer, Michael. How Much is Left?. Scientific American, September 2010, pp 74-81.

Sources

(1) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 4:16.
(2) - Whitten, Kenneth W., Davis, Raymond E., and Peck, M. Larry. General Chemistry 6th ed.; Saunders College Publishing: Orlando, FL, 2000; p 933.
(3) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 4:132.
(4) - Lide, David R. CRC Handbook of Chemistry and Physics, 84th ed.; CRC Press: Boca Raton, FL, 2002; p 4:39-4:96.
(5) - Dean, John A. Lange's Handbook of Chemistry, 11th ed.; McGraw-Hill Book Company: New York, NY, 1973; p 4:8-4:149.
(6) - Lide, David R. CRC Handbook of Chemistry and Physics, 84th ed.; CRC Press: Boca Raton, FL, 2002; p 10:147-10:148.
(7) - Speight, James. Lange's Handbook of Chemistry, 16th ed.; McGraw-Hill Professional: Boston, MA, 2004; p 1:132.
(8) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 10:178 - 10:180.
(9) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 4:133.
(10) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; pp 6:193, 12:219-220.
(11) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; pp 6:123-6:137.
(12) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; pp 6:107-6:122.
(13) - Dean, John A. Lange's Handbook of Chemistry, 12th ed.; McGraw-Hill Book Company: New York, NY, 1979; p 9:4-9:94.
(14) - Atomic Mass Data Center. http://amdc.in2p3.fr/web/nubase_en.html (accessed July 14, 2009).
(15) - Silberberg, Martin S. Chemistry: The Molecular Nature of Matter and Change, 4th ed.; McGraw-Hill Higher Education: Boston, MA, 2006, p 965.
(16) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 14:17.
(17) - Morgan, John W. and Anders, Edward, Proc. Natl. Acad. Sci. USA 77, 6973-6977 (1980)
(18) - Brownlow, Arthur. Geochemistry; Prentice-Hall, Inc.: Englewood Cliffs, NJ, 1979, pp 15-16.