Difference Between Lanthanoids and Actinoids

Introduction:

Someone rightly says it is easy to get a thousand ores but hard to get a useful mineral. The discovery of several types of minerals is one of the most notable aspects of today's world. The world is changing at a very rapid phase, and in this changing world, technology plays a very important role. Technology makes everything very easy to do. With the help of technology, anyone can discover anything, and it benefits humanity. Out of the developing technologies, the most notable development that has shaken the world is the discovery of various minerals. Daily use of minerals is increasing, and minerals are the backbone of several industries.

The role of minerals has been important since ancient times; even in earlier times, minerals were obtained with the help of traditional knowledge. They are exported and imported as per the needs of society. They are Major items in the trade basket. From history, we know that the earliest civilizations engaged in trade; they used to export and import large and deficient items, respectively.

The basis of minerals is nature, and nature provides all the necessary minerals essential for society's development. Minerals help humanity by offering several important compounds necessary for the nation's development. Due to lifestyle changes, the demand for numerous minerals is increasing daily. Due to the invention of certain technologies and the discovery of several types of minerals, the needs of future generations are fulfilled.

Several types of essential minerals are obtained easily, which are tough to acquire at any point due to technological advancements. The invention of several tools and machinery that helps extract minerals is a notable development in human history. Numerous types of minerals are obtained from the earth's crust with different physical and chemical characteristics. Scientists arranged this mineral in the periodic table for better understanding. They are grouped into several periods in the periodic table for better understanding. The development of chemistry as a separate subject is the biggest achievement in human history. Nowadays, everything is directly or indirectly linked to each other; symbiotic relationships exist between human beings and nature. Almost all fields frame policies and design their products by focusing on these symbiotic relationships. Chemistry is the subject that deals with every aspect of mineral extraction and its study. Under chemistry, scientists try to understand the composition of minerals, their behavior with other minerals, etc. Scientists arranged several types of minerals as rare earth elements in the group of Lanthanoids and Actinoids at the end of the periodic table. This article will discuss the difference between Lanthanoids and Actinoids and their main characteristics.

What are Lanthanoids?

Lanthanoids are a series of chemical elements ranging from atomic number 57 to 71. They are 15 metallic chemical elements rarely found in the earth's crust. Several other minerals, from lanthanum to scandium and yttrium, are collectively known as rare-earth elements or rare-earth metals. The chemical symbol Ln is used to denote lanthanide in chemistry. There are differences in elements found under the Lanthanoids series; for instance, all but one of the lanthanides are f-block elements. They correspond with the filling of the 4f electron shell. Lutetium is considered a d-block element; on this basis, its inclusion in the Lanthanoids series has been questioned. Also, however, scandium and yttrium in group 3 behave similarly to the other 14. All the elements in Lanthanoids tend to form a trivalent cation, Ln3+. And their chemistry is determined by an ionic radius that decreases steadily from lanthanum (La) to lutetium (Lu).

The main question is, why are they called Lanthanoids? The answer to these questions lies in the elements' physical and chemical characteristics. These elements are called lanthanides because the elements in the series are chemically similar to lanthanum. They are similar in chemical composition to lanthanum. Their physical characteristics are similar to the physical characteristics of lanthanum. They are essential rare earth elements that support the nation's development by providing solutions to several unsolved requirements.

What are Actinoids?

Actinoids are the other series of elements found in the periodic table. It comprises 15 metallic elements with atomic numbers ranging from 89 to 103. The name of this series is derived from the element actinium. Actinium is the first element in the Actinoids series; based on its names, other elements are defined. The chemical symbol of Actinoids is An; this symbol is used in a general discussion of actinide chemistry to indicate any actinide. The literal meaning of Actinoid is actinium-like, but numerous debates are going for the actual meaning.

All the elements found in the series of Actinoids are f- block elements, but there is an exception; one element known as lawrencium is the d- block element. And the inclusion of lawrencium in the series of Actinoids is always a debatable topic. Their inclusion is questionable as it is also considered a transition metal. The Actinoids series consists mostly of filling 5f electron shells despite its ground state being filled with many anomalous configurations. This involves filling the 6d shell due to inter-electronic repulsion.

The variable valence is higher in Actinoids as compared to Lanthanoids. Elements found in the Actinoids series are of great importance; they are considered rare earth elements and have very large atomic and ionic radii. They reflect large numbers of physical and chemical properties. While actinium and the late actinides, mainly from americium, behave similarly to the lanthanides. The other elements, like thorium, protactinium, and Uranium, are much more similar to transition metals in their chemistry. Also, neptunium and plutonium occupy an intermediate position. The most remarkable property of Actinoids is that they are radioactive elements, and they release energy during radioactive decay. The two most notable elements of modern times are naturally occurring Uranium and thorium. They together synthetically produce plutonium, one of the most abundant Actinoids on the earth.

The most remarkable usage of these elements is in nuclear reactors and nuclear weapons. Both Uranium and Thorium also have diverse current or historical uses. For instance, americium is used in the ionization chambers of most modern smoke detectors. Primordial thorium and Uranium occur naturally in substantial quantities. When Uranium undergoes radioactive decay, it produces a significant amount of actinium and protactinium.

Apart from that, atoms of neptunium and plutonium are occasionally produced from transmutation reactions in uranium ores. Other elements found in the Actinoids series are purely synthetic elements. From several nuclear tests, scientists concluded that at least six actinides are heavier than plutonium in the environment. Also, after analyzing the debris of a 1952 hydrogen bomb explosion, scientists found that americium, curium, berkelium, californium, einsteinium, and fermium were present in significant amounts.

Let us now discuss some of the most remarkable properties of Lanthanoids and Actinoids, which help us understand these elements separately.

Properties of Lanthanides:

Lanthanoids, as we already know, consist of some important elements that have the potential to benefit the world.

Some properties of Lanthanoids are-

1. Lanthanoids are soft metal that differs from the periodic table's other elements.
2. The color of lanthanoid elements is silvery white with light ore.
3. They are very sensitive to air; when exposed to air, their color dulls, and the brightness of elements reduces rapidly.
4. The melting point of lanthanoid elements is in the range of 1000K to 1200K. There is an exception for it; the element Samarium has a melting point of 1623K.
5. Another important property of Lanthanoids elements are they are very good conductors of heat and electricity.
6. Lanthanoid elements are normally non-reactive, but if placed under certain chemical reactions, they can react. Promethium element is a reactive element of the Lanthanoids series.
7. When atomic and ionic radii decrease from lanthanum to lutetium in Lanthanoids; it is called lanthanoid contraction.

Properties of Actinoids:

Numerous properties of Actinoids separate them from other elements found in the periodic table. Most importantly, properties that create differences between Lanthanoids and Actinoids elements are discussed below. Some of the most notable properties of Actinoids are -

1. Elements found in the Actinoids series are generally silvery in appearance.
2. Actinoid series elements are radioactive.
3. Elements found in the Actinoids series are generally very reactive; their reactivity increases when finely dividing.

In the above paragraphs, we already discussed Lanthanoids and Actinoids' properties and characteristics. Let us now discuss the most notable differences between these two groups of elements -

Lanthanoids

1. Under Lanthanoids differentiating electrons are entered into 4f orbital.
2. The binding energy found in Lanthanoid elements is higher due to 4f orbitals.
3. Lanthanoid elements show less tendency to form complexes.
4. Most of the elements belonging to lanthanoids are colorless.
5. Elements in the Lanthanoids group do not form oxo cations.
6. Apart from +3 oxidation states, lanthanoids show +2 and +4 oxidation states in a few cases.

Actinoids

1. Under Actinoids differentiating electrons enter into a 5f orbital.
2. Due to 5f, the orbital binding energy of Actinoids is lower.
3. Actinoids have shown a greater tendency to form complexes.
4. Most of the actinoids are colored. For example U3+ (red), U4+ (green) , UO22+ (yellow)
5. Elements belong to Actinoids not formed oxo cations such as UO2+2, NpO2+2, etc
6. Apart from +3 oxidation states, actinoids show higher oxidation states such as +4, +5, +6 and +7

Conclusion:

Both Lanthanoids and actinoids have the most common oxidation state. They are very useful elements found in the periodic table. They contain several rare earth elements with very high potential for use in every sector. With the increasing demand of people, the need for rare earth elements is also increased because they have the potential to benefit humanity in every possible way.