"Metal" - what is it, definition of the term
A metal is a category of chemical elements distinguished by a crystalline lattice of positively charged ions surrounded by a sea of delocalized electrons, which confers high electrical and thermal conductivity, ductility, and the ability to reflect light; these properties enable metals to be shaped, alloyed, and employed in structures, machinery, and electronic components.
Detailed information
Metallic substances are characterized by high electrical conductivity, malleability, and a crystalline lattice that permits deformation without fracture. Their atomic structure features delocalized electrons, which enable the flow of electric current and reflect light, producing a characteristic shine.
Classification divides metallic materials into pure elements (such as iron, copper, aluminum) and engineered alloys (steel, brass, bronze). Pure elements exhibit predictable mechanical and chemical behavior, while alloys combine properties to achieve specific strength, corrosion resistance, or magnetic performance.
Key physical properties include density, melting point, and hardness. Density determines weight-to-volume ratios, influencing structural applications. Melting points range from under 1 000 °C for aluminum to above 2 800 °C for tungsten, dictating suitability for high‑temperature environments. Hardness, measured on scales such as Vickers or Rockwell, guides selection for wear‑resistant components.
Common industrial uses encompass:
- Structural frameworks in construction and transportation
- Electrical wiring and circuitry
- Thermal management systems
- Protective coatings and plating
Interaction with arthropod pests involves several mechanisms. Metal‑based compounds, such as copper sulfate or zinc phosphide, serve as acaricides and insecticides, disrupting metabolic pathways in ticks, bugs, lice, and fleas. Metallic surfaces can deter attachment; smooth steel or aluminum surfaces reduce the ability of parasites to anchor, limiting infestation on medical instruments and livestock housing. Additionally, nano‑scale metallic particles (silver, titanium dioxide) exhibit antimicrobial activity, impairing the survival of ectoparasites on textiles and wound dressings.
Environmental considerations include the potential for metal leaching into soil and water, which can affect non‑target organisms. Recycling and proper disposal mitigate accumulation, preserving ecosystem balance while maintaining the functional benefits of metallic materials in pest control strategies.