Search results
Results from the WOW.Com Content Network
Chemistry is the scientific study of the properties and behavior of matter. It is a physical science within the natural sciences that studies the chemical elements that make up matter and compounds made of atoms, molecules and ions: their composition, structure, properties, behavior and the changes they undergo during reactions with other substances.
Hypervalent molecule. In chemistry, a hypervalent molecule (the phenomenon is sometimes colloquially known as expanded octet) is a molecule that contains one or more main group elements apparently bearing more than eight electrons in their valence shells. Phosphorus pentachloride ( PCl5 ), sulfur hexafluoride ( SF6 ), chlorine trifluoride ...
Chemical nomenclature. Chemical nomenclature is a set of rules to generate systematic names for chemical compounds. The nomenclature used most frequently worldwide is the one created and developed by the International Union of Pure and Applied Chemistry (IUPAC). IUPAC Nomenclature ensures that each compound (and its various isomers) have only ...
The 15-crown-5 crown ether, a cyclic oligomer, and its monomer, ethylene oxide. In chemistry and biochemistry, an oligomer ( / əˈlɪɡəmər / ⓘ) is a molecule that consists of a few repeating units which could be derived, actually or conceptually, from smaller molecules, monomers. [1] [2] [3] The name is composed of Greek elements oligo ...
Organic geochemistry, the study of the role of processes and compounds that are derived from living or once-living organisms. [13] Photogeochemistry is the study of light-induced chemical reactions that occur or may occur among natural components of the Earth's surface. [14]
Stereochemistry, a subdiscipline of chemistry, involves the study of the relative spatial arrangement of atoms that form the structure of molecules and their manipulation. The study of stereochemistry focuses on the relationships between stereoisomers , which by definition have the same molecular formula and sequence of bonded atoms ...
In organic chemistry, an addition reaction is an organic reaction where two or more molecules combine to form a larger one (the adduct ). [1] [2] Addition reactions are limited to chemical compounds that have multiple bonds, such as molecules with carbon–carbon double bonds ( alkenes ), or with triple bonds ( alkynes ), and compounds that ...
By Sarah Morland. (Reuters) - More than 2,500 people were killed or injured in gang violence in Haiti from January through March, up 53% from the last three months of 2023, the United Nations ...