Piidioksidi

Piidioksidi, also known as silicon dioxide (SiO2), is a common chemical compound and mineral that makes up a large portion of the Earth’s crust. It occurs naturally in crystalline form as quartz and in amorphous forms such as opal and fused silica. It is a major component of sand, sandstone, and many rocks, and also occurs in diatomaceous earth and other biogenic or weathered materials.

Piidioksidi has several polymorphs. Crystalline forms include quartz, cristobalite, and tridymite, while amorphous forms include fused silica, silica gel, and hydrated opal. The most familiar form is quartz, a hard, transparent to opaque mineral that appears in a wide range of geologic environments.

In terms of properties, silicon dioxide is hard (Mohs hardness about 7) and has a high melting point (about 1713 °C). It is chemically inert under ordinary conditions and is relatively insoluble in water. Pure crystalline silica is transparent and has a refractive index around 1.46 for fused silica. Its combination of strength, thermal stability, and optical properties makes it essential in many industrial applications.

Industrial use and applications are broad. Silica is the primary raw material for glassmaking and is used in cement, ceramics, and fillers. High-purity silica is crucial for semiconductor manufacturing, optical fibers, and various electronic components. Silica gels and diatomaceous earth find use in filtration, desiccation, and adsorption.

Health and safety considerations are important: inhalation of crystalline silica dust can cause lung diseases, including silicosis, and long-term exposure is regulated in many countries. Protective measures and proper ventilation are essential in workplaces handling silica material.