Question

The correct statement is: (a) \(\left[\mathrm{SiF}_{6}\right]^{2-}\) is known whereas \(\left[\mathrm{SiCl}_{6}\right]^{2-}\) is not. (b) Diamond is covalent yet it has high melting point. (c) SiO only exist at high temp. (d) All of these.

Short answer

(d) All of these.

Step-by-step solution

Analyze Option (a)

The compound \([ ext{SiF}_{6}]^{2-}\) forms because fluoride has a small ionic radius and can effectively surround the silicon atom. However, \([ ext{SiCl}_{6}]^{2-}\) does not form because chloride is larger, and it is difficult for six chloride ions to coordinate around silicon due to steric hindrance.

Analyze Option (b)

Diamond is composed of carbon atoms connected via a strong network of covalent bonds in a tetrahedral structure, which gives it an extremely high melting point. The covalent bonds in diamond make it a very strong and stable structure, requiring a great amount of energy to break.

Analyze Option (c)

Silicon monoxide (SiO) is known to exist only at high temperatures due to its instability at lower temperatures. It tends to form as an intermediate phase and is less stable when compared to other silicon oxides like SiO2.

Evaluate the Overall Statements

Since all individual statements (a), (b), and (c) are true based on the provided analysis, option (d), "All of these," is correct. This indicates that all listed statements are indeed correct insights and observations regarding the behavior and properties of the compounds mentioned.

Key concepts

Silicon Compounds

Silicon compounds are a fascinating area of study in inorganic chemistry. Silicon, a metalloid, widely forms compounds with oxygen and other halogens. Its most common oxidation state in compounds is +4, particularly in the form of oxides and halides.
One interesting aspect of silicon chemistry is the formation of hexafluorosilicate, \(\left[\mathrm{SiF}_{6}\right]^{2-}\), which is stable due to fluoride ions' small size and ability to closely shield and balance silicon's positive charge. Unlike fluorides, chlorides tend to be larger, which causes steric hindrance around silicon. This steric crowding leads to the instability of complexes like \(\left[\mathrm{SiCl}_{6}\right]^{2-}\). These steric factors play a significant role in determining the thermodynamic stability of silicon compounds.
Understanding silicon’s interactions with other elements is vital when assessing its role in a range of synthetic and biological processes. Whether focusing on the industrial processes involving silicon or its role in semiconductor technology, the unique size and charge characteristics of its bonds cannot be overstated.

Covalent Bonds

Covalent bonds are the cornerstone of molecules and compounds in chemistry. At their core, they involve the sharing of electron pairs between atoms. When we talk about covalent bonds, it’s crucial to emphasize their strength and directionality.
For instance, diamond, one of the hardest known natural materials, owes its extraordinary hardness and high melting point to a robust covalent bonding network. In diamond, each carbon atom forms covalent bonds with four other carbon atoms in a tetrahedral arrangement, creating a repeating pattern that extends throughout the material.
- The firmness of covalent bonds means that breaking them requires substantial energy. - This gives covalent substances like diamond their remarkable durability and resistance to melting. By exploring covalent bonds, we understand their pivotal role in making certain compounds stable, and incredibly strong, affecting everything from material science to biological structures.

Thermodynamic Stability

Thermodynamic stability in chemical compounds is all about understanding how energy changes affect their existence and transformations. In simple terms, a thermodynamically stable compound is one that is less likely to react or change under given conditions.
Silicon monoxide (SiO) is an intriguing example; it doesn't maintain stability at lower temperatures. It predominantly exists at high temperatures where its formation is energetically favorable. At lower temperatures, SiO prefers to convert into more stable forms like silicon dioxide (SiO2).
- Factors affecting the stability include temperature, pressure, and the presence of other substances. - High-temperature scenarios provide the kinetic energy needed to overcome the energy barriers that stabilize specific forms. Studying thermodynamic stability helps us predict reactions, synthesize new compounds, and understand the behavior of materials under varying environmental conditions.

Coordination Compounds

Coordination compounds represent an important segment of inorganic chemistry, where a central metal atom is surrounded by non-metal ions or molecules known as ligands. These ligands donate electron pairs to the metal, creating complex structures that showcase unique properties.
In the case of \(\left[\mathrm{SiF}_{6}\right]^{2-}\), silicon acts as the central atom, while the fluoride ions serve as the ligands. The relatively small size of fluoride ions helps form stable complexes due to their effective coordination with silicon.
- Coordination compounds can exhibit diverse geometries, such as octahedral, tetrahedral or square planar.- They have widespread applications including catalysis, material science, and bioinorganic chemistry.Understanding the principles behind coordination compounds allows us to design new materials and catalysts for industrial processes, illustrating the profound influence central atoms and ligands have in tuning chemical properties.