Caesium is a soft, silvery-gold alkali metal with a melting point of 28.5 °C, which makes it one of only five elemental metals that are liquid at or near room temperature. Caesium has physical and chemical properties similar to those of rubidium and potassium.
|Element category||Alkali Metal|
|Phase at STP||Solid|
|Ultimate Tensile Strength||N/A|
|Young’s Modulus of Elasticity||1.7 GPa|
|Brinell Hardness||0.14 MPa|
|Melting Point||28.4 °C|
|Boiling Point||669 °C|
|Thermal Conductivity||36 W/mK|
|Thermal Expansion Coefficient||97 µm/mK|
|Specific Heat||0.24 J/g K|
|Heat of Fusion||2.092 kJ/mol|
|Heat of Vaporization||67.74 kJ/mol|
|Electrical resistivity [nanoOhm meter]||205|
Applications of Caesium
The largest present-day use of nonradioactive caesium is in caesium formate drilling fluids for the extractive oil industry. They are also used to make special optical glass, as a catalyst promoter, in vacuum tubes and in radiation monitoring equipment. One of its most important uses is in the ‘caesium clock’ (atomic clock). These clocks are a vital part of the internetand mobile phone networks, as well as Global Positioning System (GPS) satellites. Caesium-137 is a radioisotope commonly used as a gamma-emitter in industrial applications.
Production and Price of Caesium
Raw materials prices change daily. They are primarily driven by supply, demand and energy prices. In 2019, prices of pure Caesium were at around 11000 $/kg.
Caesium is mined mostly from pollucite, while the radioisotopes, especially caesium-137, a fission product, are extracted from waste produced by nuclear reactors. Mining and refining pollucite ore is a selective process and is conducted on a smaller scale than for most other metals. The ore is crushed, hand-sorted, but not usually concentrated, and then ground. Caesium is then extracted from pollucite primarily by three methods: acid digestion, alkaline decomposition, and direct reduction.
Mechanical Properties of Caesium
Strength of Caesium
In mechanics of materials, the strength of a material is its ability to withstand an applied load without failure or plastic deformation. Strength of materials basically considers the relationship between the external loads applied to a material and the resulting deformation or change in material dimensions. In designing structures and machines, it is important to consider these factors, in order that the material selected will have adequate strength to resist applied loads or forces and retain its original shape. Strength of a material is its ability to withstand this applied load without failure or plastic deformation.
For tensile stress, the capacity of a material or structure to withstand loads tending to elongate is known as ultimate tensile strength (UTS). Yield strength or yield stress is the material property defined as the stress at which a material begins to deform plastically whereas yield point is the point where nonlinear (elastic + plastic) deformation begins.
See also: Strength of Materials
Ultimate Tensile Strength of Caesium
Ultimate tensile strength of Caesium is N/A.
Yield Strength of Caesium
Yield strength of Caesium is N/A.
Modulus of Elasticity of Caesium
The Young’s modulus of elasticity of Caesium is N/A.
Hardness of Caesium
In materials science, hardness is the ability to withstand surface indentation (localized plastic deformation) and scratching. Brinell hardness test is one of indentation hardness tests, that has been developed for hardness testing. In Brinell tests, a hard, spherical indenter is forced under a specific load into the surface of the metal to be tested.
Brinell hardness of Caesium is approximately 0.14 MPa.
The Vickers hardness test method was developed by Robert L. Smith and George E. Sandland at Vickers Ltd as an alternative to the Brinell method to measure the hardness of materials. The Vickers hardness test method can be also used as a microhardness test method, which is mostly used for small parts, thin sections, or case depth work.
Vickers hardness of Caesium is approximately N/A.
Scratch hardness is the measure of how resistant a sample is to permanent plastic deformation due to friction from a sharp object. The most common scale for this qualitative test is Mohs scale, which is used in mineralogy. The Mohs scale of mineral hardness is based on the ability of one natural sample of mineral to scratch another mineral visibly.
Caesium is has a hardness of approximately 0.2.
See also: Hardness of Materials
Caesium – Crystal Structure
A possible crystal structure of Caesium is body-centered cubic structure.
In metals, and in many other solids, the atoms are arranged in regular arrays called crystals. A crystal lattice is a repeating pattern of mathematical points that extends throughout space. The forces of chemical bonding causes this repetition. It is this repeated pattern which control properties like strength, ductility, density, conductivity (property of conducting or transmitting heat, electricity, etc.), and shape. There are 14 general types of such patterns known as Bravais lattices.
See also: Crystal Structure of Materials
Thermal Properties of Caesium
Caesium – Melting Point and Boiling Point
Melting point of Caesium is 28.4°C.
Boiling point of Caesium is 669°C.
Note that, these points are associated with the standard atmospheric pressure.
Caesium – Thermal Conductivity
Thermal conductivity of Caesium is 36 W/(m·K).
The heat transfer characteristics of a solid material are measured by a property called the thermal conductivity, k (or λ), measured in W/m.K. It is a measure of a substance’s ability to transfer heat through a material by conduction. Note that Fourier’s law applies for all matter, regardless of its state (solid, liquid, or gas), therefore, it is also defined for liquids and gases.
Coefficient of Thermal Expansion of Caesium
Linear thermal expansion coefficient of Caesium is 97 µm/(m·K)
Thermal expansion is generally the tendency of matter to change its dimensions in response to a change in temperature. It is usually expressed as a fractional change in length or volume per unit temperature change.
Caesium – Specific Heat, Latent Heat of Fusion, Latent Heat of Vaporization
Specific heat of Caesium is 0.24 J/g K.
Heat capacity is an extensive property of matter, meaning it is proportional to the size of the system. Heat capacity C has the unit of energy per degree or energy per kelvin. When expressing the same phenomenon as an intensive property, the heat capacity is divided by the amount of substance, mass, or volume, thus the quantity is independent of the size or extent of the sample.
Latent Heat of Fusion of Caesium is 2.092 kJ/mol.
Latent Heat of Vaporization of Caesium is 67.74 kJ/mol.
Latent heat is the amount of heat added to or removed from a substance to produce a change in phase. This energy breaks down the intermolecular attractive forces, and also must provide the energy necessary to expand the gas (the pΔV work). When latent heat is added, no temperature change occurs. The enthalpy of vaporization is a function of the pressure at which that transformation takes place.
Caesium – Electrical Resistivity – Magnetic Susceptibility
Electrical property refers to the response of a material to an applied electric field. One of the principal characteristics of materials is their ability (or lack of ability) to conduct electrical current. Indeed, materials are classified by this property, that is, they are divided into conductors, semiconductors, and nonconductors.
See also: Electrical Properties
Magnetic property refers to the response of a material to an applied magnetic field. The macroscopic magnetic properties of a material are a consequence of interactions between an external magnetic field and the magnetic dipole moments of the constituent atoms. Different materials react to the application of magnetic field differently.
See also: Magnetic Properties
Electrical Resistivity of Caesium
Electrical resistivity of Caesium is 205 nΩ⋅m.
Electrical conductivity and its converse, electrical resistivity, is a fundamental property of a material that quantifies how Caesium conducts the flow of electric current. Electrical conductivity or specific conductance is the reciprocal of electrical resistivity.
Magnetic Susceptibility of Caesium
Magnetic susceptibility of Caesium is N/A.
In electromagnetism, magnetic susceptibility is the measure of the magnetization of a substance. Magnetic susceptibility is a dimensionless proportionality factor that indicates the degree of magnetization of Caesium in response to an applied magnetic field.
Application and prices of other elements