Silicon is the fundamental component of integrated circuits. Si has the same structure as diamond. (b) Silicon readily reacts to form silicon dioxide, SiO2, which is quite hard and is insoluble in water. Is SiO2 most likely a molecular, metallic, ionic, or covalent-network solid?

Key Concepts

Types of Solids

Solids can be classified into different categories based on their bonding and structure. Molecular solids consist of molecules held together by intermolecular forces, metallic solids are composed of metal atoms sharing electrons, ionic solids are formed from the electrostatic attraction between ions, and covalent-network solids feature a continuous network of covalent bonds. Understanding these categories helps in predicting the properties of materials.

Silicon Dioxide Structure

Silicon dioxide (SiO2) has a three-dimensional network structure where each silicon atom is covalently bonded to four oxygen atoms, and each oxygen atom is bonded to two silicon atoms. This arrangement creates a strong, rigid lattice that contributes to its hardness and insolubility in water. Recognizing this structure is crucial for identifying SiO2 as a covalent-network solid.

Properties of Covalent-Network Solids

Covalent-network solids, like SiO2, exhibit unique properties such as high melting points, hardness, and low electrical conductivity. These properties arise from the strong covalent bonds that extend throughout the material, making them very stable. Understanding these characteristics is essential for determining the classification of SiO2 in the context of solid-state chemistry.