molekulái

Molekulái, or molecules, are the fundamental units of chemical substances that consist of two or more atoms bonded together, forming discrete entities with defined structures and properties. They are the smallest units that retain the characteristic chemical behavior of a compound.

Most molecules are held together by covalent bonds, which involve the sharing of electron pairs between atoms. Some substances are held together mainly by ionic bonds, forming lattices of ions rather than discrete molecules, and metals exhibit metallic bonding with a delocalized electron system. The arrangement of atoms within a molecule—its geometry—strongly influences its physical and chemical properties.

Molecular polarity, shape, and size affect properties such as solubility, boiling and melting points, and reactivity. Symmetrical molecules tend to be nonpolar, while asymmetrical ones are often polar, leading to distinct interactions with solvents and other molecules. Isomers share the same molecular formula but have different arrangements, resulting in different properties and activities.

Common small molecules include water (H2O), oxygen (O2), carbon dioxide (CO2), and methane (CH4). Larger molecules, called macromolecules, form the basis of organic chemistry and biology, including carbohydrates, proteins, and nucleic acids.

Techniques to study molecules include spectroscopy, mass spectrometry, infrared spectroscopy, nuclear magnetic resonance, and X-ray crystallography. These methods help determine composition, structure, and dynamics. Molekulái are central to chemistry, biology, materials science, and medicine, providing the link between atomic interactions and bulk properties.