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  2. Ball-and-stick model - Wikipedia

    en.wikipedia.org/wiki/Ball-and-stick_model

    Double and triple bonds are usually represented by two or three curved rods, respectively, or alternately by correctly positioned sticks for the sigma and pi bonds. In a good model, the angles between the rods should be the same as the angles between the bonds , and the distances between the centers of the spheres should be proportional to the ...

  3. Collision theory - Wikipedia

    en.wikipedia.org/wiki/Collision_theory

    The rate for a bimolecular gas-phase reaction, A + B → product, predicted by collision theory is [6] = = ⁡ ()where: k is the rate constant in units of (number of molecules) −1 ⋅s −1 ⋅m 3.

  4. Quadruple bond - Wikipedia

    en.wikipedia.org/wiki/Quadruple_bond

    A quadruple bond is a type of chemical bond between two atoms involving eight electrons. This bond is an extension of the more familiar types of covalent bonds: double bonds and triple bonds. [1] Stable quadruple bonds are most common among the transition metals in the middle of the d-block, such as rhenium, tungsten, technetium, molybdenum and ...

  5. Wikipedia : Vital articles/Level/5/Physical sciences/Chemistry

    en.wikipedia.org/wiki/Wikipedia:Vital_articles/...

    Triple bond; Hydrogen bond ; Ionic bonding Metallic ... Pi bond; Sigma bond; Electrochemistry. This section contains 15 articles. Electrochemical cell.

  6. Orbital hybridisation - Wikipedia

    en.wikipedia.org/wiki/Orbital_hybridisation

    Chemist Linus Pauling first developed the hybridisation theory in 1931 to explain the structure of simple molecules such as methane (CH 4) using atomic orbitals. [2] Pauling pointed out that a carbon atom forms four bonds by using one s and three p orbitals, so that "it might be inferred" that a carbon atom would form three bonds at right angles (using p orbitals) and a fourth weaker bond ...

  7. Graphene - Wikipedia

    en.wikipedia.org/wiki/Graphene

    It is an allotrope of carbon in the form of a plane of sp 2-bonded atoms with a molecular bond length of 0.142 nm (1.42 Å). In a graphene sheet, each atom is connected to its three nearest carbon neighbors by σ-bonds, and a delocalized π-bond, which contributes to a valence band that extends over the whole sheet.

  8. Molecular symmetry - Wikipedia

    en.wikipedia.org/wiki/Molecular_symmetry

    For example, the water molecule has three normal modes of vibration: symmetric stretch in which the two O-H bond lengths vary in phase with each other, asymmetric stretch in which they vary out of phase, and bending in which the bond angle varies. The molecular symmetry of water is C 2v with four irreducible representations A 1, A 2, B 1 and B 2.

  9. Gaussian integral - Wikipedia

    en.wikipedia.org/wiki/Gaussian_integral

    A different technique, which goes back to Laplace (1812), [3] is the following. Let = =. Since the limits on s as y → ±∞ depend on the sign of x, it simplifies the calculation to use the fact that e −x 2 is an even function, and, therefore, the integral over all real numbers is just twice the integral from zero to infinity.