Zinc oxide is a stable, semiconducting inorganic compound widely employed for its catalytic and electronic properties.
","applications":["Catalysis","Gas sensors","Optoelectronics","Pigments","Sunscreen formulations"],"wikipedia_url":"https://en.wikipedia.org/wiki/Zinc_oxide","meta_description":"Zinc oxide is a thermodynamically stable semiconducting oxide used in catalysis and electronics. Explore its properties and role in industrial applications.","overview_html":"Zinc oxide is a thermodynamically stable semiconducting material that serves as a cornerstone in modern materials science. Its robust electronic structure and high structural versatility make it a preferred candidate for various catalytic and optoelectronic applications.
Because it resides on the convex hull, this compound exhibits exceptional stability, ensuring reliable performance in demanding chemical environments. It is widely utilized in industrial processes where its surface reactivity and electronic properties can be precisely tuned.
","comparison_html":"Within the diverse family of spinel and related oxides, ZnO stands out as a highly accessible and extensively studied semiconductor compared to more complex perovskites like LaNiO3 or LaMnO3. While materials such as MgAl2O4 often serve as structural substrates, ZnO is frequently prioritized in catalytic research for its distinct electronic character and ease of synthesis.
"},"verified_page":{"common_name":"Zinc oxide","aliases":["zinc white","Chinese white","philosopher's wool","flowers of zinc"],"meta_description":"ZnO (zinc oxide) is a thermodynamically stable, wide-band-gap n-type semiconducting oxide used in rubber vulcanization, catalysis, varistors, and UV-blocking…","answer_first":"ZnO is zinc oxide, a thermodynamically stable binary compound of zinc and oxygen. It usually crystallizes in the hexagonal wurtzite structure and is a wide-band-gap semiconductor that is normally n-type as grown. It is widely used as a rubber vulcanization activator, as a component of copper-based methanol synthesis catalysts, in varistors, and as an ultraviolet filter.","sections":[{"question":"What is ZnO and what structure does it adopt?","answer":"ZnO is a binary oxide of zinc and oxygen. At ambient conditions it adopts the hexagonal wurtzite structure, in which every zinc and oxygen atom is tetrahedrally coordinated. A metastable cubic zinc-blende form can be grown under certain conditions, such as on cubic substrates, and at high pressure ZnO changes to a rocksalt structure."},{"question":"What is ZnO used for?","answer":"Zinc oxide is used in chemical manufacturing, electronics, and personal care. It is an essential activator in rubber vulcanization. In heterogeneous catalysis it is a key component of the copper/zinc oxide/alumina catalysts used for industrial methanol synthesis, and it is studied for carbon dioxide hydrogenation. In devices, its wide direct band gap, piezoelectricity, and the nonlinear electrical behaviour of its ceramics make it useful for varistors, gas sensors, transparent conducting layers (when doped, for example with aluminium), and acoustic-wave devices. Its strong ultraviolet absorption and low skin toxicity have made it a widely used mineral sunscreen filter, and it is also used as a white pigment (zinc white)."},{"question":"How stable and synthesizable is ZnO?","answer":"ZnO is a thermodynamically stable compound at ambient conditions and has been made and used on a large scale for a long time. Industrial routes include the indirect (French) process, in which zinc metal is vaporized and oxidized, and the direct (American) process, in which zinc ore is reduced and the resulting zinc vapour is oxidized. In the laboratory it is made by thermal decomposition or calcination of zinc salts and hydroxides, hydrothermal growth, and sol-gel deposition. These methods give bulk ceramics, single crystals, thin films, and many kinds of nanostructures."},{"question":"Is ZnO a semiconductor and what does that imply?","answer":"Yes. ZnO is a wide-band-gap semiconductor that is normally n-type as grown. The origin of this unintentional n-type conductivity is still debated. Oxygen vacancies and zinc interstitials were long blamed, but first-principles studies suggest oxygen vacancies are deep donors, so hydrogen and other impurities such as aluminium or gallium are also strong candidates. Reliable p-type doping is still difficult to achieve. Gases adsorbing on the surface change its conductivity, which is the basis for ZnO gas sensors. In varistors, electrical barriers at the grain boundaries of doped ZnO ceramics give the strongly nonlinear current-voltage response used for surge protection."},{"question":"How does ZnO compare to CuO, NiO, and other oxides?","answer":"In CuO and NiO the metal d shells are only partly filled, which gives these oxides magnetic ordering and colour. Zinc in ZnO is Zn2+ with a completely filled 3d shell, so ZnO is diamagnetic and white, with a wide direct band gap. Wide-gap oxides such as the spinel MgAl2O4 or the perovskite LaAlO3 are electrical insulators. ZnO is unusual because it combines transparency to visible light with electrical conduction that can be tuned by doping."}],"faq":[{"q":"Is ZnO the same as calamine?","a":"Not exactly. Calamine lotion is mainly zinc oxide with a small amount of iron(III) oxide (ferric oxide), which gives its pink colour. The name calamine has also been used for zinc ore minerals."},{"q":"What crystal structure does ZnO normally have?","a":"At ambient temperature and pressure ZnO normally crystallizes in the hexagonal wurtzite structure. A rocksalt form appears at high pressure, and a metastable zinc-blende form can be grown under special conditions."},{"q":"Is zinc oxide safe in sunscreen?","a":"Zinc oxide is widely regarded as a safe and effective mineral (physical) sunscreen ingredient that protects against a broad range of UV wavelengths. Studies indicate little penetration beyond the outer layer of intact skin."},{"q":"Why is ZnO used with copper in methanol synthesis catalysts?","a":"ZnO helps keep copper well dispersed and slows sintering. It is also thought to create highly active sites where zinc species meet the copper surface, which improves the catalyst's hydrogenation activity."},{"q":"Does ZnO conduct electricity?","a":"Highly pure ZnO is fairly resistive, but as-grown material is usually n-type. Donor impurities such as hydrogen, aluminium, or gallium can make it highly conductive. Whether native defects such as oxygen vacancies contribute is still debated."}],"applications":["Rubber vulcanization activator","Component of Cu/ZnO/Al2O3 methanol synthesis catalysts","Varistors for electrical surge protection","UV-blocking mineral filter in sunscreens and cosmetic ointments","Piezoelectric transducers and acoustic wave devices","Gas sensors","Transparent conducting films (doped ZnO)","White pigment in coatings and artists' paints (zinc white)"],"wikipedia_url":"https://en.wikipedia.org/wiki/Zinc_oxide","reviewed_at":"2026-10-01 19:28:25.014918+00:00"},"citations":[{"source":"oqmd","attribution":"Data from the OQMD (oqmd.org). Cite: Saal et al., JOM 65, 1501 (2013); Kirklin et al., npj Comp. Mater. 1, 15010 (2015).","doi":"10.1007/s11837-013-0755-4","license_spdx":"CC-BY-4.0"},{"source":"jarvis","attribution":"Data from JARVIS (jarvis.nist.gov), NIST. Cite: Choudhary et al., npj Comp. Mater. 6, 173 (2020).","doi":"10.1038/s41524-020-00440-1","license_spdx":"LicenseRef-US-Gov-PD"},{"source":"materials_project","attribution":"Data from the Materials Project (materialsproject.org). Cite: Jain et al., APL Materials 1, 011002 (2013).","doi":"10.1063/1.4812323","license_spdx":"CC-BY-4.0"}],"structure_image_url":"https://prd-lg-assets.sfo3.digitaloceanspaces.com/structures/OZn.png","structure_source":"Materials Project"}