General
States
Energies
Oxidation & Electrons
Appearance & Characteristics
Reactions & Compounds
Radius
Conductivity
Abundance & Isotopes
States
Energies
Oxidation & Electrons
Appearance & Characteristics
Reactions & Compounds
Radius
Conductivity
Abundance & Isotopes
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55
Cs
132.9054
Cesium |
Cesium atomic clock. Accurate to 1 second in 60 million years.
(Photo: NASA)
(Photo: NASA)
General:
Name: Cesium
Type: Alkali Metal
Density @ 293 K: 1.873 g/cm3
Discovery of Cesium
Cesium was discovered by Robert Bunsen and Gustav Kirchhoff in 1860, when they analyzed the spectrum of mineral water.
Cesium was the first element discovered using a spectroscope. A year earlier, Bunsen and Kirchhoff had developed a spectroscope that could examine the colored flame of substances in detail by looking at their emission spectra through a prism. When studying the spectrum of the residue from some spa mineral water, they found a series of emission spectra lines that did not correspond to any known element.
Bunsen and Kirchhoff named the element cesium, from the Latin word 'caesius', meaning sky blue, after the blue lines they saw in the spectrum.
The Latin spelling is still reflected in British English where cesium is spelt 'caesium'.
In 1861 Bunsen and Kirchhoff also discovered rubidium by the same method.
Type: Alkali Metal
Density @ 293 K: 1.873 g/cm3
Discovery of Cesium
Cesium was discovered by Robert Bunsen and Gustav Kirchhoff in 1860, when they analyzed the spectrum of mineral water.
Cesium was the first element discovered using a spectroscope. A year earlier, Bunsen and Kirchhoff had developed a spectroscope that could examine the colored flame of substances in detail by looking at their emission spectra through a prism. When studying the spectrum of the residue from some spa mineral water, they found a series of emission spectra lines that did not correspond to any known element.
Bunsen and Kirchhoff named the element cesium, from the Latin word 'caesius', meaning sky blue, after the blue lines they saw in the spectrum.
The Latin spelling is still reflected in British English where cesium is spelt 'caesium'.
In 1861 Bunsen and Kirchhoff also discovered rubidium by the same method.
Symbol: Cs
Atomic weight: 132.9055
Atomic volume: 71.07 cm3/mol
Atomic weight: 132.9055
Atomic volume: 71.07 cm3/mol
States
State (s, l, g): solid
Melting point: 301.6 K (28.4 oC)
Melting point: 301.6 K (28.4 oC)
Boiling point: 943.2 K (670 oC)
Energies
Specific heat capacity: 0.24 J g-1 K-1
Heat of fusion: 2.092 kJ mol-1
1st ionization energy: 375.7 kJ mol-1
3rd ionization energy: 3400 kJ mol-1
Heat of fusion: 2.092 kJ mol-1
1st ionization energy: 375.7 kJ mol-1
3rd ionization energy: 3400 kJ mol-1
Heat of atomization: 76 kJ mol-1
Heat of vaporization : 67.740 kJ mol-1
2nd ionization energy: 2234.3 kJ mol-1
Electron affinity: 45.506 kJ mol-1
Heat of vaporization : 67.740 kJ mol-1
2nd ionization energy: 2234.3 kJ mol-1
Electron affinity: 45.506 kJ mol-1
Oxidation & Electrons
Shells: 2,8,18,18,8,1
Minimum oxidation number: 0
Min. common oxidation no.: 0
Electronegativity (Pauling Scale): 0.79
Minimum oxidation number: 0
Min. common oxidation no.: 0
Electronegativity (Pauling Scale): 0.79
Electron configuration: [Xe] 6s1
Maximum oxidation number: 3
Max. common oxidation no.: 3
Polarizability volume: 59.6 Å3
Maximum oxidation number: 3
Max. common oxidation no.: 3
Polarizability volume: 59.6 Å3
Appearance & Characteristics
Structure: bcc: body-centered cubic
Hardness: 0.2 mohs
Hardness: 0.2 mohs
Cesium (preceded by rubidium) reacting with water.
High purity cesium crystals under argon.
(Photo: Dennis "S.K", GNU Free Documentation License).
(Photo: Dennis "S.K", GNU Free Documentation License).
Color: yellow/silvery
Harmful effects:
Cesium must be kept under an inert liquid/gas or in a vacuum to protect it from air and water. Cesium compounds are considered to be mildy toxic.
Characteristics:
Cesium is silvery-gold, soft, ductile alkali metal. It is liquid in a warm room, melting at 28.4 oC (83.1 oF).
Cesium is one of the few metals that is liquid near room temperature. The others are gallium, francium and mercury.
Cesium is an extremely reactive metal and the most alkaline of the elements. It reacts explosively upon contact with water producing cesium hydroxide (CsOH), an extremely strong base that can rapidly corrode glass.
Uses:
Cesium is used in atomic clocks, which are incredibly accurate. NIST-F1, America's primary time and frequency standard, is a cesium fountain atomic clock developed at the NIST laboratories in Boulder, Colorado. NIST-F1 contributes to the international group of atomic clocks that define Coordinated Universal Time (UTC), the official world time. As scientists continue to improve its technology, uncertainty in NIST-F1's measurement of time is continually improving. Currently it neither gains nor loses as much a second in more than 60 million years - but see strontium.
Cesium is also used in photoelectric cells and as a catalyst in the hydrogenation of organic compounds. The metal is used as a 'getter' in vacuum tubes.
Cesium hydroxide is used to etch silicon.
Harmful effects:
Cesium must be kept under an inert liquid/gas or in a vacuum to protect it from air and water. Cesium compounds are considered to be mildy toxic.
Characteristics:
Cesium is silvery-gold, soft, ductile alkali metal. It is liquid in a warm room, melting at 28.4 oC (83.1 oF).
Cesium is one of the few metals that is liquid near room temperature. The others are gallium, francium and mercury.
Cesium is an extremely reactive metal and the most alkaline of the elements. It reacts explosively upon contact with water producing cesium hydroxide (CsOH), an extremely strong base that can rapidly corrode glass.
Uses:
Cesium is used in atomic clocks, which are incredibly accurate. NIST-F1, America's primary time and frequency standard, is a cesium fountain atomic clock developed at the NIST laboratories in Boulder, Colorado. NIST-F1 contributes to the international group of atomic clocks that define Coordinated Universal Time (UTC), the official world time. As scientists continue to improve its technology, uncertainty in NIST-F1's measurement of time is continually improving. Currently it neither gains nor loses as much a second in more than 60 million years - but see strontium.
Cesium is also used in photoelectric cells and as a catalyst in the hydrogenation of organic compounds. The metal is used as a 'getter' in vacuum tubes.
Cesium hydroxide is used to etch silicon.
Reactions & Compounds
Reaction with air: vigorous, ⇒ Cs2O
Reaction with 15 M HNO3: vigorous, ⇒ CsNO3
Oxide(s): Cs2O, Cs2, Cs2O2
Hydride(s): CsH
Reaction with 15 M HNO3: vigorous, ⇒ CsNO3
Oxide(s): Cs2O, Cs
Hydride(s): CsH
Reaction with 6 M HCl: vigorous, ⇒ H2, CsCl
Reaction with 6 M NaOH: vigorous, ⇒ H2, CsOH
Chloride(s): CsCl
Reaction with 6 M NaOH: vigorous, ⇒ H2, CsOH
Chloride(s): CsCl
Radius
Atomic radius: 260 pm
Ionic radius (2+ ion): pm
Ionic radius (2- ion): pm
Ionic radius (2+ ion): pm
Ionic radius (2- ion): pm
Ionic radius (1+ ion): 181 pm
Ionic radius (3+ ion): pm
Ionic radius (1- ion): pm
Ionic radius (3+ ion): pm
Ionic radius (1- ion): pm
Conductivity
Thermal conductivity: 35.9 W m-1 K-1
Electrical conductivity: 5.3 x 106 S m-1
Abundance & Isotopes
Abundance earth's crust: 3 parts per million by weight, 0.5 parts per million by moles
Abundance solar system: 8 parts per billion by weight, 70 parts per trillion by moles
Cost, pure: $1100 per 100g
Cost, bulk: $ per 100g
Source: Cesium is found in the minerals pollucite and lepidolite. Commercially, most cesium is produced as a byproduct of the production of lithium metal. More than two-thirds of the world's reserves of Cesium - 110,000 tonnes - are found at Bernic Lake, Manitoba, Canada.
Isotopes: Cesium has 36 isotopes whose half-lives are known, with mass numbers 112 to 148. Of these, one is stable: 133Cs.
Abundance solar system: 8 parts per billion by weight, 70 parts per trillion by moles
Cost, pure: $1100 per 100g
Cost, bulk: $ per 100g
Source: Cesium is found in the minerals pollucite and lepidolite. Commercially, most cesium is produced as a byproduct of the production of lithium metal. More than two-thirds of the world's reserves of Cesium - 110,000 tonnes - are found at Bernic Lake, Manitoba, Canada.
Isotopes: Cesium has 36 isotopes whose half-lives are known, with mass numbers 112 to 148. Of these, one is stable: 133Cs.
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