Question

\(\left[\mathrm{SiO}_{4}\right]^{4-}\) has tetrahedral structure the silicate formed by using three oxygen has a: (a) Two dimensional sheet structure (b) Pyrosilicate structure (c) Linear polymeric structure (d) Three dimensional structure.

Short answer

The silicate formed has a three-dimensional structure.

Step-by-step solution

Understanding the Silicate Ion \\(\text{[SiO}_4\text{]}^{4-}\\)

The ion \(\text{[SiO}_4\text{]}^{4-}\) forms a tetrahedral structure where each silicon atom is surrounded by four oxygen atoms. In isolated \(\text{[SiO}_4\text{]}^{4-}\) ions, the oxygen atoms are not shared with other tetrahedra, resulting in discrete units.

Examining the Oxygen Sharing

In the next step, we consider sharing of oxygen atoms. If three oxygen atoms are shared, as implied in the problem, the structure can no longer be tetrahedral. Instead, shared oxygen atoms between tetrahedra often lead to ring structures or other linked configurations.

Considering Pyrosilicate Structure

Pyrosilicates are formed when two tetrahedra share one oxygen atom, forming \(\text{[Si}_2\text{O}_7\text{]}^{6-}\) units, which is not the case when three oxygen atoms are shared. Thus, pyrosilicate does not fit.

Exploring Three-Dimensional Structures

A three-dimensional structure involves extensive sharing of oxygen atoms across multiple tetrahedra. Sharing three oxygen atoms directly leads to fused structures, often resulting in a more networked and dimensional shape.

Concluding the Structure Type

When three oxygen atoms in each tetrahedron are shared, a highly networked structure is formed. This kind of extensive oxygen sharing corresponds with a three-dimensional silicate structure rather than linear or sheet structures.

Key concepts

Tetrahedral Structure

In the world of silicate minerals, the building block is often the tetrahedral structure. Silicate tetrahedra are made up of one silicon atom centrally located and bonded to four oxygen atoms. This configuration creates a three-dimensional geometric shape known as a tetrahedron.

Think of a tetrahedron like a three-sided pyramid with a triangular base. In this arrangement, silicon forms strong covalent bonds with each oxygen atom, giving the silicate structure its distinct properties. The isolated tetrahedra are at the core of many silicate minerals and serve as the base for more complex structures.

• Silicone atom at the center.
• Four oxygen atoms at the vertices.
• Basic building block for silicate structures.

Understanding this foundational structure is essential before exploring how these tetrahedra connect or share oxygen.

Oxygen Sharing in Silicates

The magic in silicate structures happens when these tetrahedra begin to share their oxygen atoms. The sharing of oxygen among tetrahedra creates a variety of structures ranging from simple to intricate and large network forms.

Depending on the number of oxygen atoms shared, different structures can emerge:

• Sharing no oxygen leads to isolated units.
• Sharing one oxygen results in dimers, known as pyrosilicates.
• Sharing two oxygens forms chain or ring silicates.
• Sharing three or more oxygens allows complex networks to form.

This sharing affects the overall structure of the silicon-oxygen framework drastically. When three oxygen atoms are shared as in our problem scenario, a robust and more interconnected network is established.
Such connectivity is key for creating the three-dimensional networks found in many common minerals.

Three-Dimensional Silicate Structure

As sharing oxygen atoms across tetrahedra becomes more common, the connectivity starts to extend in all three spatial dimensions. This results in three-dimensional silicate structures, which are highly networked and appear in many natural and synthetic settings.

In a three-dimensional silicate structure, each tetrahedron typically shares three or four oxygen atoms with neighboring tetrahedra. This extensive sharing creates a solid network that can appear as sheets, frameworks, or even intricate lattice structures.
Some familiar examples include:

• Quartz, which forms a continuous three-dimensional network where each oxygen atom is shared.
• Feldspar, where complex frameworks interlock through shared oxygen.

Such structures give rise to the unique physical properties of these minerals, including their strength and resistance to heat and pressure. Understanding these three-dimensional forms helps us appreciate the versatility and significance of silicate minerals in the Earth’s crust.