CÄSIUM

Einführung

Ordnungszahl: 55
Gruppe: 1 or I A
Atomares Gewicht: 132.90545
Periode: 6
CAS-Nummer: 7440-46-2

Einstufung

Metall
Nonmetal
metalloider
Alkalimetall
Erdalkalimetalls
Übergangsmetall
Chalkogenhaltige
Halogen
Edelgas
Lanthanoid
Actinoidenelemente
Seltene Erden
Platingruppenmetall
Transurane
Keine Stabile Isotope
Solide
Flüssigkeit
Gas
Solide (Prognostizierte)

Beschreibung • Verwendung / Funktion

Cesium was discovered spectroscopically by Bunsen and Kirchhoff in 1860 in mineral water from Durkheim. Cesium, an alkali metal, occurs in lepidolite,pollucite (a hydrated silicate of aluminum and cesium), and in other sources. One of the world’s richest sources of cesium is located at Bernic Lake,Manitoba. The deposits are estimated to contain 300,000 tons of pollucite, averaging 20% cesium. It can be isolated by electrolysis of the fused cyanideand by a number of other methods. Very pure, gas-free cesium can be prepared by thermal decomposition of cesium azide. The metal is characterizedby a spectrum containing two bright lines in the blue along with several others in the red, yellow, and green. It is silvery white, soft, and ductile. Itis the most electropositive and most alkaline element. Cesium, gallium, and mercury are the only three metals that are liquid at room temperature.Cesium reacts explosively with cold water, and reacts with ice at temperatures above –116°C. Cesium hydroxide, the strongest base known, attacksglass. Because of its great affinity for oxygen the metal is used as a “getter” in electron tubes. It is also used in photoelectric cells, as well as a catalystin the hydrogenation of certain organic compounds. The metal has recently found application in ion propulsion systems. Cesium is used in atomicclocks, which are accurate to 5 s in 300 years. Its chief compounds are the chloride and the nitrate. Cesium has 52 isotopes and isomers with massesranging from 112 to 148. The present price of cesium is about $40/g (99.98%). 1

• "used in some photoelectric cells" 2

Physikalische Eigenschaften

Schmelzpunkt:3*  28.5 °C = 301.65 K = 83.3 °F
Siedepunkt:3* 671 °C = 944.15 K = 1239.8 °F
Sublimationspunkt:3 
Dreifacher Punkt:3 
Kritischer Punkt:3 1665 °C = 1938.15 K = 3029 °F 3
Dichte:4  1.93 g/cm3

* - at 1 atm

Elektronenkonfiguration

Elektronenkonfiguration: [Xe] 6s1
Block: s
Höchster besetztes Energieniveau: 6
Valenzelektronen: 1

Quantenzahlen:

n = 6
ℓ = 0
m = 0
ms = +½

Kleben

Elektronegativität (Pauling-Skala):5 0.79
Electropositivity (Pauling-Skala): 3.21
Elektronenaffinität:6 0.471626 eV
oxidations~~POS=TRUNC: +1
Arbeitsfuntkion:7 1.90 eV = 3.0438E-19 J

Ionisationspotential   eV 8  kJ/mol  
Ionisationspotential   eV 8  kJ/mol  
1 3.8939    375.7
Ionisationspotential   eV 8  kJ/mol  
2 23.15745    2234.4

Thermochemie

Spezifische Wärme: 0.242 J/g°C 9 = 32.163 J/mol°C = 0.058 cal/g°C = 7.687 cal/mol°C
Wärmeleitfähigkeit: 59 (W/m)/K, 27°C 10
Schmelzwärme: 2.092 kJ/mol 11 = 15.7 J/g
Verdampfungswärme: 67.74 kJ/mol 12 = 509.7 J/g
Aggregatszustand Bildungsenthalpie (ΔHf°)13 Entropie (S°)13 Gibbs-Energie (ΔGf°)13
(kcal/mol) (kJ/mol) (cal/K) (J/K) (kcal/mol) (kJ/mol)
(g) 56 234.304 50.30 210.4552 44 184.096
(s) 0 0 20.35 85.1444 0 0
(ℓ) 0.499 2.087816 22.01 92.08984 0.006 0.025104
(g) 18.3 76.5672 41.94 175.47696 11.9 49.7896

Isotopes

Nuklid Masse 14 Halbwertzeit 14 Kernspin 14 Bindungsenergie
112Cs 111.95030(33)# 500(100) μs 1+# 907.53 MeV
113Cs 112.94449(11) 16.7(7) μs 5/2+# 924.92 MeV
114Cs 113.94145(33)# 0.57(2) s (1+) 932.99 MeV
115Cs 114.93591(32)# 1.4(8) s 9/2+# 950.38 MeV
116Cs 115.93337(11)# 0.70(4) s (1+) 958.45 MeV
117Cs 116.92867(7) 8.4(6) s (9/2+)# 975.83 MeV
118Cs 117.926559(14) 14(2) s 2 983.90 MeV
119Cs 118.922377(15) 43.0(2) s 9/2+ 991.98 MeV
120Cs 119.920677(11) 61.2(18) s 2(-#) 1,000.05 MeV
121Cs 120.917229(15) 155(4) s 3/2(+) 1,017.43 MeV
122Cs 121.91611(3) 21.18(19) s 1+ 1,025.50 MeV
123Cs 122.912996(13) 5.88(3) min 1/2+ 1,033.58 MeV
124Cs 123.912258(9) 30.9(4) s 1+ 1,041.65 MeV
125Cs 124.909728(8) 46.7(1) min 1/2(+) 1,059.03 MeV
126Cs 125.909452(13) 1.64(2) min 1+ 1,067.10 MeV
127Cs 126.907418(6) 6.25(10) h 1/2+ 1,075.18 MeV
128Cs 127.907749(6) 3.640(14) min 1+ 1,083.25 MeV
129Cs 128.906064(5) 32.06(6) h 1/2+ 1,091.32 MeV
130Cs 129.906709(9) 29.21(4) min 1+ 1,099.39 MeV
131Cs 130.905464(5) 9.689(16) d 5/2+ 1,107.46 MeV
132Cs 131.9064343(20) 6.480(6) d 2+ 1,115.53 MeV
133Cs 132.905451933(24) STABIL 7/2+ 1,123.60 MeV
134Cs 133.906718475(28) 2.0652(4) a 4+ 1,131.68 MeV
135Cs 134.9059770(11) 2.3(3)E+6 a 7/2+ 1,139.75 MeV
136Cs 135.9073116(20) 13.16(3) d 5+ 1,147.82 MeV
137Cs 136.9070895(5) 30.1671(13) a 7/2+ 1,155.89 MeV
138Cs 137.911017(10) 33.41(18) min 3- 1,154.65 MeV
139Cs 138.913364(3) 9.27(5) min 7/2+ 1,162.72 MeV
140Cs 139.917282(9) 63.7(3) s 1- 1,170.79 MeV
141Cs 140.920046(11) 24.84(16) s 7/2+ 1,169.54 MeV
142Cs 141.924299(11) 1.689(11) s 0- 1,177.62 MeV
143Cs 142.927352(25) 1.791(7) s 3/2+ 1,185.69 MeV
144Cs 143.932077(28) 994(4) ms 1(-#) 1,184.44 MeV
145Cs 144.935526(12) 582(6) ms 3/2+ 1,192.51 MeV
146Cs 145.94029(8) 0.321(2) s 1- 1,191.27 MeV
147Cs 146.94416(6) 0.235(3) s (3/2+) 1,199.34 MeV
148Cs 147.94922(62) 146(6) ms 1,207.41 MeV
149Cs 148.95293(21)# 150# ms [>50 ms] 3/2+# 1,206.17 MeV
150Cs 149.95817(32)# 100# ms [>50 ms] 1,214.24 MeV
151Cs 150.96219(54)# 60# ms [>50 ms] 3/2+# 1,213.00 MeV
Werte markiert # sind nicht rein aus experimentellen Daten abgeleitet, aber zumindest teilweise von der systematischen Trends. Dreht mit schwachen Zuordnung Argumente in Klammern eingeschlossen sind. 14

Fülle

Erde - Ausgangsverbindungen: halide salts and brines 15
Erde - Meerwasser: 0.0003 mg/L 16
Erde -  Kruste:  3 mg/kg = 0.0003% 16
Erde -  Gesamt:  15.3 ppb 17
Der Planet Merkur) -  Gesamt:  2.5 ppb 17
Venus -  Gesamt:  17.0 ppb 17
Chondrite - Gesamt: 0.14 (relative to 106 atoms of Si) 18
Menschlicher Körper - Gesamt: 0.000002% 19

Verbindungen

Sicherheitsinformation


Datenblatt zur Materialsicherheit - ACI Alloys, Inc.

Für mehr Informationen

Externe Links:

Quellen

(1) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 4:8.
(2) - Whitten, Kenneth W., Davis, Raymond E., and Peck, M. Larry. General Chemistry 6th ed.; Saunders College Publishing: Orlando, FL, 2000; p 928.
(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.
(19) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 7:17.