süsinikdioksüdid

süsinikdioksüdid (CO₂) is a colorless, odorless inorganic compound consisting of one carbon atom double‑bonded to two oxygen atoms. It is a simple yet essential molecule in the Earth's atmosphere and a major greenhouse gas. Chemically, CO₂ is a weak acid; in aqueous solution it forms carbonic acid (H₂CO₃), which plays a crucial role in regulating pH in biological systems and in the oceans. The molecule is linear, with a bond angle of 180°, and it has no permanent dipole moment, though it exhibits quadrupole interactions.

Physical properties include a melting point of −78.5 °C and a boiling point of 31.0 °C under standard atmospheric pressure. It is non‑flammable and non‑toxic at normal concentrations, but high levels can cause asphyxiation by displacing oxygen. Its solubility in water is relatively low, about 1.5 g per liter at 20 °C, and it dissolves more readily in alkaline solutions.

Natural sources of CO₂ include respiration of organisms, volcanic activity, and the decomposition of organic matter. Anthropogenic emissions primarily arise from the combustion of fossil fuels, deforestation, and cement manufacturing. The concentration of CO₂ in the atmosphere has risen from approximately 280 ppm before the Industrial Revolution to over 420 ppm in recent years, contributing to global climate change. Managing CO₂ emissions is a key focus of international environmental policy.

Applications of CO₂ span multiple industries. It is used in carbonation of beverages, fire suppression systems, and as a solvent in supercritical fluid extraction. In agriculture, elevated CO₂ levels can enhance photosynthetic rates, a phenomenon exploited in controlled‑environment agriculture. Research on carbon capture and storage (CCS) focuses on chemically binding CO₂ to reduce atmospheric concentrations, while emerging technologies investigate its conversion into useful chemicals and fuels through catalytic processes.