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  2. Linnett double-quartet theory - Wikipedia

    en.wikipedia.org/wiki/Linnett_Double-Quartet_Theory

    The dot-and-cross diagram of the LDQ structure of the ground state of acetylene is shown on the left and that of the first excited state of acetylene is shown on the right. The nuclei are as indicated and the electrons are denoted by either dots or crosses, depending on their relative spins.

  3. Magnesium oxide - Wikipedia

    en.wikipedia.org/wiki/Magnesium_oxide

    Magnesium oxide (Mg O), or magnesia, is a white hygroscopic solid mineral that occurs naturally as periclase and is a source of magnesium (see also oxide). It has an empirical formula of MgO and consists of a lattice of Mg 2+ ions and O 2− ions held together by ionic bonding .

  4. Molecular orbital diagram - Wikipedia

    en.wikipedia.org/wiki/Molecular_orbital_diagram

    Molecular orbital diagram of NO. Nitric oxide is a heteronuclear molecule that exhibits mixing. The construction of its MO diagram is the same as for the homonuclear molecules. It has a bond order of 2.5 and is a paramagnetic molecule. The energy differences of the 2s orbitals are different enough that each produces its own non-bonding σ orbitals.

  5. Lewis structure - Wikipedia

    en.wikipedia.org/wiki/Lewis_structure

    [1] [2] [3] Introduced by Gilbert N. Lewis in his 1916 article The Atom and the Molecule, a Lewis structure can be drawn for any covalently bonded molecule, as well as coordination compounds. [4] Lewis structures extend the concept of the electron dot diagram by adding lines between atoms to represent shared pairs in a chemical bond.

  6. Lewis acids and bases - Wikipedia

    en.wikipedia.org/wiki/Lewis_acids_and_bases

    A center dot may also be used to represent a Lewis adduct, such as Me 3 B·NH 3. Another example is boron trifluoride diethyl etherate , BF 3 ·Et 2 O . In a slightly different usage, the center dot is also used to represent hydrate coordination in various crystals, as in MgSO 4 ·7H 2 O for hydrated magnesium sulfate , irrespective of whether ...

  7. Ethenone - Wikipedia

    en.wikipedia.org/wiki/Ethenone

    Ethenone is a highly reactive gas (at standard conditions) and has a sharp irritating odour.It is only reasonably stable at low temperatures (−80 °C). It must therefore always be prepared for each use and processed immediately, otherwise a dimerization to diketene occurs or it reacts to polymers that are difficult to handle.

  8. Dewar–Chatt–Duncanson model - Wikipedia

    en.wikipedia.org/wiki/Dewar–Chatt–Duncanson...

    H 2 O the C−C bond length has increased to 134 picometres from 133 pm for ethylene. In the nickel compound Ni(C 2 H 4)(PPh 3) 2 the value is 143 pm. The interaction also causes carbon atoms to "rehybridise" from sp 2 towards sp 3, which is indicated by the bending of the hydrogen atoms on the ethylene back away from the metal. [4]

  9. Energy profile (chemistry) - Wikipedia

    en.wikipedia.org/wiki/Energy_profile_(chemistry)

    Any chemical structure that lasts longer than the time for typical bond vibrations (10 −13 – 10 −14 s) can be considered as intermediate. [4] Figure 5:Potential Energy Surface and Corresponding 2-D Reaction Coordinate Diagram derived from the plane passing through the minimum energy pathway between A and C and passing through B