Diagonal Relationship Between Boron and Silicon

Diagonal Relationship of B and Si

Edited By Shivani Poonia | Updated on Jul 02, 2025 06:35 PM IST

Diagonal relationship in the periodic according to _userdata, relates to the similarity between elements the diagonally adjacent in the periodic table. Boron and Silicon are metalloids, one in Group 13, while the other one is in Group 14. That is the kind of relationship that does exist between them. It occurs because when we go diagonally through the periodic table, the increase of atomic number is balanced by changes in atomic size and electronegativity so that similar chemical properties come to be observed. For example, Boron and Silicon can both have covalent bonding and have nearly the same electronegativity and ionization energy.

This Story also Contains

Boron exhibits resemblance with its diagonal element silicon of group 14:
Development of the Concept on Different Aspects
Relevance/Application
Some Solved Examples
Summary

Diagonal Relationship of B and Si

Boron exhibits resemblance with its diagonal element silicon of group 14:

Both boron and silicon are non-metals.
Both are semiconductors.
Both form covalent hydrides i.e, boranes and silanes.
Both form solid oxides that dissolve in alkalies forming borates and silicates respectively.

Development of the Concept on Different Aspects

Chemically, Boron and Silicon share a lot of features in common. These elements combine to form compounds that have the same structures. For example, boron forms borates, whereas silicon forms silicates; both compounds are the major constituents of glass and ceramics. These two members also form tetrahedral structured compounds in borates and silicates. In addition, Boron and Silicon are semiconductors; therefore, they have contributed a lot to the electronic industry. In this case, Boron is a doping agent in increasing the conductivity of semiconductors, while Silicon creates the spine in which most electronic devices are manufactured in the semiconductor industry. These parallels are further driven and underscored by the importance of their diagonal relationship in the different applications of industry.

Relevance/Application

The diagonal from Boron to Silicon is a phenomenally influential factor, both theoretically and in practice. This relationship will hence be very important in materials science since it can be used in the development of new material structures that have the desired properties. For example, borosilicate glass forms material that is very resistant to thermal and chemical attacks due to the pairing of boron and silicon; hence, it finds wideness of application in glassworks in laboratories and cookware. In electronics, their semi-conductor qualities are applied in the development of more efficient and small-sized electronic components. Another very important material, used in the making of most devices, is transistors and integrated circuits, which are the basics of most modern electronic devices; they would be the case for Boron-doped Silicon wafers. This knowledge is therefore a way of improving upon empirical chemical bonding and structure of molecules to represent very useful information in advancing many scientific fields.

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Some Solved Examples

Example 1

Question: Which of the following elements does not show a diagonal relationship?

B – Si
Li – Mg
Be – Al
Li – Na

Solution:
Li–Mg, B–Si, and Be–Al show a diagonal relationship but Li and Na do not show a diagonal relationship as both belong to the same group and are not placed diagonally.
Hence, the correct answer is option (4).

Example 2

Question:

Which of the following shows a diagonal relationship with B?

Solution:
Si shows a diagonal relationship with B due to their similar physical and chemical properties.
Therefore, the correct answer is option (2).

Example 3

Question: Which of the following pairs of elements form acidic oxides?

B and Fe
B and Si
Mg and Si
B and Mg

Solution:
Oxides of B and Si are both acidic and can be reduced by a limited amount of Mg.
Both are readily soluble in alkalies:

B₂O₃+3Mg→3MgO+2B
SiO₂+2Mg→2MgO+Si

Hence, the correct answer is option (2).

Summary

The diagonal relationship of Boron and Silicon is a vivid image of the intricate and curious connections between elements in the periodic table. The parallelism defined by similar chemical behavior due to its diagonal position makes this relationship, thus, not only an academic concept but an affecting feature in many ways of application to industry requirements. The similarities in the behavior of Boron and Silicon, right through from the enhancement of the properties of materials to powering advances in the world of electronics, are a pointer to the understanding of periodic trends—in this way, we will delve into the behavior of elements and open avenues for potential scientific and technological advancement.

Frequently Asked Questions (FAQs)

1. 1. Relation to the diagonal in the periodic table:

When some elements on the periodic table that happen to be diagonally adjacent to each other exhibit similar properties, then there is a diagonal relationship. This results from the balancing of atomic size versus electronegativity across different periods and groups coming out to be similar, thus causing similar chemical properties.

2. 2. Why do boron and silicon have a diagonal relationship?

Their diagonal relation could be explained by the fact that Boron and Silicon exhibit electronegativities, ionization energies, and a possibility of forming covalent bonds of similar magnitude. All these chemical properties result from their diagonal position in the periodic table.

3. 3. What are some examples that illustrate the diagonal relationship between Boron and Silicon?

Examples include emissions in the same structure, such as borates B₂O₃ and silicates SiO₂, common in glass and ceramics. These elements exist in tetrahedral structures within their compounds.

4. 4. How is the diagonal relationship between Boron and Silicon relevant in electronics?

Both Boron and silicon are semiconductors such that in industry, boron dopes silicon, a process that increases the semiconductor's conductance, and it acts as the basis for making transistors, and hence, eventually computers, which form part of most modern electronics

5. What is the diagonal relationship in the periodic table?

The diagonal relationship refers to similarities in properties between elements diagonally adjacent to each other in the second and third periods of the periodic table. This relationship is particularly notable between boron (B) and silicon (Si).

6. Why do boron and silicon exhibit a diagonal relationship?

Boron and silicon exhibit a diagonal relationship due to their similar atomic sizes and comparable electronegativity values. This similarity arises from the interplay between increasing atomic number and nuclear charge across a period, and increasing atomic size down a group.

7. How does the atomic size of boron compare to that of silicon?

The atomic size of boron is similar to that of silicon, despite silicon being in a lower period. This is because the increase in nuclear charge across the period (for boron) is roughly balanced by the increase in atomic size down the group (for silicon).

8. What role does electron deficiency play in the diagonal relationship between B and Si?

Electron deficiency is a crucial factor in the diagonal relationship between B and Si. Both elements have a tendency to form electron-deficient compounds, leading to similar chemical behaviors such as Lewis acidity and complex formation.

9. Why do B and Si both form strong bonds with oxygen?

B and Si both form strong bonds with oxygen due to their similar electronegativity values and their ability to form multiple covalent bonds. This results in the formation of stable oxide networks in both cases, reflecting their diagonal relationship.

10. What role does electronegativity play in the diagonal relationship between B and Si?

Electronegativity plays a crucial role in the diagonal relationship between B and Si. Both elements have similar electronegativity values (B: 2.04, Si: 1.90 on the Pauling scale), which contributes to their comparable chemical behaviors in many reactions.

11. What is the difference between the oxides of B and Si compared to other group 13 and 14 elements?

Unlike other elements in their respective groups, B and Si form acidic oxides. In contrast, other group 13 elements (like Al) form amphoteric oxides, while other group 14 elements (like Ge, Sn, Pb) form increasingly basic oxides down the group.

12. How does the diagonal relationship influence the hydride formation of B and Si?

Both B and Si form covalent hydrides (boranes and silanes) that are reactive and can act as reducing agents. This similarity in hydride behavior is not shared with other elements in their respective groups, highlighting the diagonal relationship.

13. How does the melting point of B compare to Si, and why?

B and Si have relatively high melting points compared to other elements in their respective groups. This is due to the strong covalent bonds in their crystal structures, which is a consequence of their diagonal relationship and similar bonding tendencies.

14. What is the significance of the +3 oxidation state in B and Si?

Both B and Si can exhibit a +3 oxidation state, although it's more common for B. This shared oxidation state is another manifestation of their diagonal relationship and similar electronic structures.

15. How does the diagonal relationship affect the oxide formation of B and Si?

Both B and Si form acidic oxides (B2O3 and SiO2) that readily dissolve in alkaline solutions. This similarity in oxide behavior is a direct consequence of their diagonal relationship and comparable electronegativity values.

16. Why do B and Si both form strong covalent bonds in their compounds?

B and Si both form strong covalent bonds due to their similar electronegativity values and their tendency to achieve a stable electron configuration through sharing electrons. This covalent nature is a key aspect of their diagonal relationship.

17. How does the diagonal relationship affect the ability of B and Si to form complexes?

Both B and Si have a tendency to form complexes by accepting electron pairs from Lewis bases. This behavior is due to their similar electron-deficient nature and ability to expand their octet, which is a characteristic of their diagonal relationship.

18. Why do both B and Si compounds often act as Lewis acids?

B and Si compounds often act as Lewis acids because both elements have vacant p orbitals that can accept electron pairs. This shared characteristic is a result of their similar electronic structures and is a key aspect of their diagonal relationship.

19. How does the reactivity of B and Si with halogens compare to other elements in their groups?

B and Si react with halogens to form covalent halides, unlike some other elements in their groups that form more ionic halides. This similarity in halide formation is another example of their diagonal relationship.

20. How does the diagonal relationship influence the ability of B and Si to form clusters?

Both B and Si have the ability to form cluster compounds, where multiple atoms of the element bond together. This tendency is related to their electron deficiency and covalent bonding nature, which are aspects of their diagonal relationship.

21. How does the diagonal relationship affect the tendency of B and Si to form polymeric structures?

Both B and Si have a strong tendency to form polymeric structures due to their ability to form strong covalent bonds and their electron deficiency. This shared characteristic is a direct consequence of their diagonal relationship.

22. What is the significance of the sp2 hybridization in B and sp3 hybridization in Si?

While B typically exhibits sp2 hybridization and Si exhibits sp3 hybridization, both elements can adopt multiple hybridization states. This flexibility in bonding is related to their similar valence electron configurations and is part of their diagonal relationship.

23. How does the diagonal relationship influence the reactivity of B and Si with water?

Both B and Si react with water, but in different ways. B forms boric acid (H3BO3), while Si forms silicic acid (H4SiO4). Despite the differences, both reactions result in the formation of acidic products, reflecting their diagonal relationship.

24. Why do both B and Si form strong bonds with carbon?

B and Si both form strong bonds with carbon due to their similar electronegativity values and their ability to form covalent bonds. This results in important classes of compounds like organoboranes and organosilanes, highlighting their diagonal relationship.

25. How does the diagonal relationship affect the ability of B and Si to form double bonds?

Both B and Si can form double bonds, although they do so less readily than carbon. This ability is related to their similar electronic structures and is another aspect of their diagonal relationship.

26. What is the significance of the similar first ionization energies of B and Si?

The similar first ionization energies of B and Si (B: 800.6 kJ/mol, Si: 786.5 kJ/mol) contribute to their comparable chemical behaviors. This similarity is a result of the balance between increasing nuclear charge and atomic size, which is a key aspect of their diagonal relationship.

27. How does the diagonal relationship influence the ability of B and Si to form network solids?

Both B and Si have a strong tendency to form network solids with high melting points. This is due to their ability to form strong covalent bonds in three dimensions, which is a characteristic of their diagonal relationship.

28. Why do both B and Si form stable hydrides with chain structures?

B and Si both form stable hydrides with chain structures (boranes and silanes) due to their similar bonding capabilities and electron deficiency. This shared characteristic is a direct consequence of their diagonal relationship.

29. How does the diagonal relationship affect the catalytic properties of B and Si compounds?

Compounds of both B and Si can act as catalysts in various reactions, often due to their Lewis acidic nature. This shared catalytic ability is related to their similar electronic structures and is an aspect of their diagonal relationship.

30. What is the significance of the similar electron affinities of B and Si?

The similar electron affinities of B and Si contribute to their comparable chemical behaviors, particularly in their ability to form anions. This similarity is another manifestation of their diagonal relationship.

31. How does the diagonal relationship influence the ability of B and Si to form intercalation compounds?

Both B and Si can form intercalation compounds, where other species can be inserted between layers of their structures. This shared characteristic is related to their similar bonding properties and is part of their diagonal relationship.

32. Why do both B and Si form strong bonds with nitrogen?

B and Si both form strong bonds with nitrogen due to their similar electronegativity values and their ability to form multiple covalent bonds. This results in important classes of compounds like boron nitride and silicon nitride, reflecting their diagonal relationship.

33. How does the diagonal relationship affect the ability of B and Si to form alloys?

Both B and Si can form alloys with various metals, often improving the properties of the resulting materials. This shared ability is related to their similar atomic sizes and bonding properties, which are aspects of their diagonal relationship.

34. What is the significance of the similar atomic radii of B and Si?

The similar atomic radii of B and Si (B: 87 pm, Si: 111 pm) contribute to their comparable chemical behaviors, particularly in terms of bond lengths and molecular geometries. This similarity is a key aspect of their diagonal relationship.

35. How does the diagonal relationship influence the ability of B and Si to form glasses?

Both B and Si are important glass-forming elements due to their ability to form strong, directional covalent bonds in three dimensions. This shared characteristic is a direct consequence of their diagonal relationship.

36. Why do both B and Si compounds often have high thermal stability?

Compounds of both B and Si often exhibit high thermal stability due to the strength of their covalent bonds. This shared property is related to their similar bonding capabilities and is an aspect of their diagonal relationship.

37. How does the diagonal relationship affect the ability of B and Si to form coordination compounds?

Both B and Si can form coordination compounds, acting as Lewis acids to accept electron pairs from ligands. This shared behavior is due to their similar electron-deficient nature and is a key aspect of their diagonal relationship.

38. What is the significance of the similar electronegativities of B and Si in their compound formation?

The similar electronegativities of B and Si result in the formation of compounds with comparable bond polarities. This similarity contributes to their analogous chemical behaviors and is a crucial aspect of their diagonal relationship.

39. How does the diagonal relationship influence the ability of B and Si to form pi bonds?

Both B and Si can form pi bonds, although less readily than carbon. This ability is related to their similar electronic structures and vacant p orbitals, which is another manifestation of their diagonal relationship.

40. Why do both B and Si play important roles in semiconductor technology?

B and Si are both crucial in semiconductor technology due to their ability to form covalent network structures and their electron-deficient nature. B is often used as a dopant in Si semiconductors, highlighting their complementary properties and diagonal relationship.

41. How does the diagonal relationship affect the ability of B and Si to form organometallic compounds?

Both B and Si form important classes of organometallic compounds (organoboranes and organosilanes) due to their ability to form strong covalent bonds with carbon. This shared characteristic is a direct consequence of their diagonal relationship.

42. What is the significance of the similar electron configurations of B and Si?

The similar valence electron configurations of B ([He]2s²2p¹) and Si ([Ne]3s²3p²) contribute to their comparable chemical behaviors, particularly in their bonding properties. This similarity is a fundamental aspect of their diagonal relationship.

43. How does the diagonal relationship influence the ability of B and Si to form nanostructures?

Both B and Si can form various nanostructures, such as nanotubes and nanoparticles, due to their ability to form strong covalent bonds in different arrangements. This shared characteristic is related to their similar bonding properties and is part of their diagonal relationship.

44. Why do both B and Si play important roles in materials science?

B and Si are both crucial in materials science due to their unique bonding properties, ability to form network structures, and their roles in creating advanced materials. This shared importance is a reflection of their diagonal relationship and similar chemical behaviors.