Search results
Results from the WOW.Com Content Network
In chemistry, the history of molecular theory traces the origins of the concept or idea of the existence of strong chemical bonds between two or more atoms . A modern conceptualization of molecules began to develop in the 19th century along with experimental evidence for pure chemical elements and how individual atoms of different chemical ...
Molecular geometry. Geometry of the water molecule with values for O-H bond length and for H-O-H bond angle between two bonds. Molecular geometry is the three-dimensional arrangement of the atoms that constitute a molecule. It includes the general shape of the molecule as well as bond lengths, bond angles, torsional angles and any other ...
Valence shell electron pair repulsion ( VSEPR) theory ( / ˈvɛspər, vəˈsɛpər / VESP-ər, [ 1]: 410 və-SEP-ər[ 2]) is a model used in chemistry to predict the geometry of individual molecules from the number of electron pairs surrounding their central atoms. [ 3] It is also named the Gillespie-Nyholm theory after its two main developers ...
Cis–trans isomerism, also known as geometric isomerism, describes certain arrangements of atoms within molecules. The prefixes " cis " and " trans " are from Latin: "this side of" and "the other side of", respectively. [ 1] In the context of chemistry, cis indicates that the functional groups (substituents) are on the same side of some plane ...
Bent's rule provides an additional level of accuracy to valence bond theory. Valence bond theory proposes that covalent bonds consist of two electrons lying in overlapping, usually hybridised, atomic orbitals from two bonding atoms. The assumption that a covalent bond is a linear combination of atomic orbitals of just the two bonding atoms is ...
In chemistry, trigonal planar is a molecular geometry model with one atom at the center and three atoms at the corners of an equilateral triangle, called peripheral atoms, all in one plane. [ 1] In an ideal trigonal planar species, all three ligands are identical and all bond angles are 120°. Such species belong to the point group D 3h.
In molecular biology, the term double helix[ 1] refers to the structure formed by double-stranded molecules of nucleic acids such as DNA. The double helical structure of a nucleic acid complex arises as a consequence of its secondary structure, and is a fundamental component in determining its tertiary structure.
Tetrahedral molecular geometry. In a tetrahedral molecular geometry, a central atom is located at the center with four substituents that are located at the corners of a tetrahedron. The bond angles are cos −1 (− 1⁄3) = 109.4712206...° ≈ 109.5° when all four substituents are the same, as in methane ( CH4) [ 1][ 2] as well as its ...