Metal quality becomes crucial when building something meant to last long and withstand the wear and tear of life. Sacrificing quality often leads to a subpar product.
The unique properties of metals make them more interesting than others, and the market offers various metal varieties, each with its own perks.
Metals vary in quality, with some offering flexibility, others being harder, and some falling into the category of soft metals.
You might wonder why anyone would need a soft metal for anything. Indeed, our perception of metal tends to associate it with heaviness.
However, soft metals do exist and find diverse applications. For instance, some soft metals are used in jewelry making, while others find use in the construction industry.
While you can easily find soft metals in the market, determining the softest metal can be challenging due to their shared properties.
In this article, we will explore the primary contender for the title of the softest metal in the world, focusing on Caesium.
What Is The Softest Metal?
When referring to softness in the context of metals, it indicates the metal’s malleability—the ease with which the metal can be hammered into thin sheets or cut with a knife.
Soft metals, like gold, silver, lead, and copper, are commonly used in jewelry due to their malleability.
Some might not be aware, but aluminum is also considered a soft metal, although not as malleable as others.
Determining the softest metal in the market can be challenging, as they share similar properties.
The Mohs hardness scale is often used to assess the softness of various metals. In this regard, Caesium stands out as one of the softest metals.
Introduction Of Caesium
Caesium is an alkali metal with the lowest ionization potential among all the elements.
It is non-radioactive and, along with gallium, francium, rubidium, and mercury, one of the few pure metals that can be liquid at room temperature.
Caesium reacts explosively with cold water, and the temperature should stay above -177 degrees Fahrenheit to avoid such reactions.
Caesium is found in nature, and estimates suggest there are around 300,000 tons of Caesium-polluted ore in Bernic Lake, Manitoba, averaging 20% Caesium by weight.
It has approximately 39 isotopes, with Cs-133 being the only naturally stable isotope. Other isotopes have various half-lives, with Cs-137 being significant in nuclear power plants and atomic detonation of weapons.
Explosive Aspect
Caesium is known for its high reactivity and is one of the heaviest alkali metals.
It reacts explosively when it comes into contact with water, producing hydrogen gas that ignites due to the thermal energy released. This results in an explosion.
Caesium’s reactivity extends to its ability to ignite the air due to Caesium hydroxide and other oxides.
Caesium Inclusion in Everyday Lives
Caesium can be hazardous due to its mild toxicity, but it seldom comes into contact with humans.
The presence of potassium makes Caesium toxic, and adding it to the diet is highly discouraged.
Studies on lab rats have shown that exposure to Caesium resulted in all the rats dying.
Caesium isotopes, such as Cs-134 and Cs-137, can cause radioactivity issues depending on the area of exposure.
Properties Of Caesium Breakdown
Caesium is the softest metal in the world, possessing a mild, silvery-gold appearance and malleability. It is the most electropositive element and reacts explosively with cold water at temperatures above -116 degrees Celsius.
Scientific Breakdown Of Caesium
| Atomic number | 55 |
| Atomic mass | 132.9054 g.mol -1 |
| Electronegativity according to Pauling | 0.7 |
| Melting point | 28.5°C, 83.3°F, 301.7 K |
| Period | 6 |
| Boiling point | 671°C, 1240°F, 944 K |
| Density | 1.9 g.cm3 at 20°C |
| Melting point | 28.4 °C |
| Relative atomic mass | 132.905 |
| Boiling point | 669 °C |
| Van Der Waals radius | 0.267 nm |
| Ionic radius | 0.167 |
| CAS number | 7440-46-2 |
| Key isotopes | 133Cs |
| Isotopes | 12 |
| Electronic shell | [ Xe ] 6s1 |
| The energy of the first ionization | 375.6 kJ.mol -1 |
| Discovered by Fustov Kirchhoff in | 1860 |
History Behind Caesium
The traces of Caesium’s history date back to 1800 when Carl Plattner investigated the mineral pollucite or Caesium aluminum silicate, accounting for only 93% of its elements due to limited material for analysis.
Later, Gustav Kirchhoff and Robert Bunsen discovered the existence of Caesium in 1860 through the examination of a mineral from Durkheim.
Caesium Appearance
Caesium appears as a soft, gold-colored material that reacts to air and water, causing explosive reactions in water.
Caesium Uses
Caesium finds various applications, including drilling fluid for the oil industry, catalyst promoters in optical glass industries, and in vacuum tubes and radiation monitoring equipment.
It is also used in atomic clocks for accurate time measurement and in GPS satellites.
Caesium Atomic Data
Here is the detailed list of all the atomic data present in Caesium.
| 1. Atomic radius, non-bonded (Å) | 3.43 |
| 2. Covalent radius (Å) | 2.38 |
| 3. Electron affinity (kJ mol−1) | 45.505 |
| 4. Electronegativity (Pauling scale) | 0.79 |
| 5. Ionization energies (kJ mol−1) | |
| 1st – | 375.705 |
| 2nd- | 2234.353 |
| 3rd – | |
| 4th – | |
| 5th – | |
| 6th – | |
| 7th – | |
| 8th – |
Caesium Oxidation States And Isotopes
This section covers the oxidation states and isotopes of Caesium.
| Common oxidation states | 1 |
| Isotopes | |
| Isotope | 133Cs |
| Atomic mass | 132.905 |
| Natural abundance (%) | 100 |
| Half-life – | |
| Mode of decay – |
Caesium Supply Risk
Here we are going to cover the supply risk Caesium.
| Relative supply risk | Unknown |
| Crustal abundance (ppm) | 3 |
| Recycling rate (%) | Unknown |
| Substitutability | Unknown |
| Production concentration (%) | Unknown |
| Reserve distribution (%) | Unknown |
| Top 3 producers | Unknown |
| Top 3 reserve holders | Unknown |
| The political stability of top producer | Unknown |
| The political stability of top reserve holder | Unknown |
Advanced pressure and temperature data
| Specific heat capacity (J kg−1 K−1) | 242 |
| Young’s modulus (GPa) | Unknown |
| Shear modulus (GPa) | Unknown |
| Bulk modulus (GPa) | 1.6 |
Vapour pressure [Ref – Link]
| Temperature (K) | Pressure (Pa) |
| 400 | 0.394 |
| 600 | – |
| 800 | – |
| 1000 | – |
| 1200 | -Baro |
| 1400 | – |
| 1800 | – |
| 2000 | – |
| 2200 | – |
| 2400 | – |
Other Soft Metals
Aside from Caesium, other soft metals include lead, mercury, lithium, and aluminum. While they are considered soft, they can be hazardous if not handled properly.
Conclusion
Caesium is the softest metal in the world, and its unique properties make it an interesting element.
It is essential to handle all soft metals, including Caesium, with proper care and guidance, as their properties can pose risks if not managed correctly.