elektronika: Nonmetallic material

Evidence: 100 • authority: 72

Nonmetallic material, or in nontechnical terms a nonmetal, refers to materials which are not metals. Depending upon context it is used in slightly different ways. In everyday life it would be a generic term for those materials such as plastics, wood or ceramics which are not typical metals such as the iron alloys used in bridges. In some areas of chemistry, particularly the periodic table, it is used for just those chemical elements which are not metallic at standard temperature and pressure conditions. It is also sometimes used to describe broad classes of dopant atoms in materials. In general usage in science, it refers to materials which do not have electrons that can readily move around…

Evidence: 45 • authority: 72

Niobium compounds are compounds containing the element niobium (Nb). In many ways, niobium is similar to tantalum and zirconium. It reacts with most nonmetals at high temperatures; with fluorine at room temperature; with chlorine at 150 °C and hydrogen at 200 °C; and with nitrogen at 400 °C, with products that are frequently interstitial and nonstoichiometric. The metal begins to oxidize in air at 200 °C. It resists corrosion by fused alkalis and by acids, including aqua regia, hydrochloric, sulfuric, nitric and phosphoric acids. Niobium is attacked by hydrofluoric acid and hydrofluoric/nitric acid mixtures. Although niobium exhibits all of the formal oxidation states from +5 to −1, the mos…

Evidence: 42 • authority: 72

In electromagnetism, a dielectric (or dielectric medium) is an electrical insulator that can be polarised by an applied electric field. When a dielectric material is placed in an electric field, electric charges do not flow through the material as they do in an electrical conductor, because they have no loosely bound, or free, electrons that may drift through the material, but instead they shift, only slightly, from their average equilibrium positions, causing dielectric polarisation. Because of dielectric polarisation, positive charges are displaced in the direction of the field and negative charges shift in the direction opposite to the field. This creates an internal electric field that…

Evidence: — • authority: 72

An ion () is an atom or molecule with a net electrical charge. The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by convention. The net charge of an ion is not zero because its total number of electrons is unequal to its total number of protons. A cation is a positively charged ion with fewer electrons than protons (e.g. K+ (potassium ion)) while an anion is a negatively charged ion with more electrons than protons (e.g. Cl− (chloride ion) and OH− (hydroxide ion)). Opposite electric charges are pulled towards one another by electrostatic force, so cations and anions attract…

Evidence: — • authority: 72

The metallic elements in the periodic table located between the transition metals to their left and the chemically weak nonmetallic metalloids to their right have received many names in the literature, such as post-transition metals, poor metals, other metals, p-block metals, basic metals, and chemically weak metals. Physically, these metals are soft (or brittle), have poor mechanical strength, and usually have melting points lower than those of the transition metals. Being close to the metal-nonmetal border, their crystalline structures tend to show covalent or directional bonding effects, having generally greater complexity or fewer nearest neighbours than other metallic elements. Chemica…

Evidence: — • authority: 72

The word metalloid comes from the Latin metallum ("metal") and the Greek oeidḗs ("resembling in form or appearance"). However, there is no standard definition of a metalloid and no complete agreement on which elements are metalloids. Despite the lack of specificity, the term remains in use in the literature. The six commonly recognised metalloids are boron, silicon, germanium, arsenic, antimony and tellurium. Five elements are less frequently so classified: carbon, aluminium, selenium, polonium and astatine. On a standard periodic table, all eleven elements are in a diagonal region of the p-block extending from boron at the upper left to astatine at lower right. Some periodic tables include…

Evidence: — • authority: 92

Nonzero spontaneous electric polarization in metals: novel predictive methods and applications.. Ferroelectricity in metals has advanced since the initial discovery of nonmagnetic ferroelectric-like metal LiOsO[Formula: see text], anchored in the Anderson and Blount prediction. However, evaluating the spontaneous electric polarization (SEP) of this metal has been hindered by experimental and theoretical obstacles. The experimental challenge arises from difficulties in switching polarization using an external electric field, while the theoretical limitation lies in existing methods applicable only to nonmetals. Zabalo and Stengel (Phys Rev Lett 126:127601, 2021, https://doi.org/10.1103/PhysR…

Evidence: — • authority: 92

Fundamentals of Flexoelectricity, Materials and Emerging Opportunities Toward Strain-Driven Nanocatalysts.. Flexoelectricity, an intrinsic property observed in materials under nonuniform deformation, entails a coupling between polarization and strain gradients. Recent catalyst advancements have reignited interest in flexoelectricity, particularly at the nanoscale, where pronounced strain gradients promote robust flexoelectric effects. This paper comprehensively examines flexoelectricity, encompassing methodologies for precise measurement, elucidating its distinctions from related phenomena, and exploring its potential applications in augmenting catalytic properties. So far, the greatest pot…