Sinkoksid

Sinkoksid, or zinc oxide (ZnO), is an inorganic compound of zinc. It appears as a white solid, typically as a fine powder, with low solubility in water. It has a hexagonal wurtzite crystal structure and a high melting point around 1975 °C. ZnO is a wide-bandgap semiconductor with a band gap of about 3.37 eV at room temperature and an exciton binding energy near 60 meV, which gives it strong ultraviolet absorption and potential light emission in some conditions.

Chemically, zinc oxide is amphoteric: it dissolves in acids to form zinc salts and reacts with strong bases to form zincates. It can be produced by direct oxidation of zinc, calcination of zinc carbonate or zinc hydroxide, or by precipitation from zinc salts followed by heating. Industrially, ZnO is also obtained as a byproduct in zinc refining and has long been used as a white pigment, known as zinc white.

Applications are diverse. As a pigment, it provides whiteness and opacity in paints and coatings. In cosmetics, ZnO serves as a UV absorber, offering protection in the UV-A and UV-B ranges while remaining relatively transparent in visible light. In rubber, plastics, ceramics, and glass, it acts as an additive to improve properties and processing. In electronics, ZnO is used as a semiconductor material and in devices such as varistors; nanostructured ZnO is studied for photocatalysis, sensors, and light-emitting devices.

Safety and environmental aspects: bulk ZnO is considered of relatively low toxicity, but inhalation of fine powders can be hazardous, and appropriate industrial hygiene measures should be followed to minimize exposure.