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  2. Substitution reaction - Wikipedia

    en.wikipedia.org/wiki/Substitution_reaction

    Substitution reactions in organic chemistry are classified either as electrophilic or nucleophilic depending upon the reagent involved, whether a reactive intermediate involved in the reaction is a carbocation, a carbanion or a free radical, and whether the substrate is aliphatic or aromatic. Detailed understanding of a reaction type helps to ...

  3. Displacement (geometry) - Wikipedia

    en.wikipedia.org/wiki/Displacement_(geometry)

    Displacement is the shift in location when an object in motion changes from one position to another. [2] For motion over a given interval of time, the displacement divided by the length of the time interval defines the average velocity (a vector), whose magnitude is the average speed (a scalar quantity).

  4. Displacement - Wikipedia

    en.wikipedia.org/wiki/Displacement

    Displacement (geometry), is the difference between the final and initial position of a point trajectory (for instance, the center of mass of a moving object).The actual path covered to reach the final position is irrelevant.

  5. Quantum chemistry composite methods - Wikipedia

    en.wikipedia.org/wiki/Quantum_chemistry...

    Removing steps 3 and 4 and relying only on the MP2 result from step 5 is significantly cheaper and only slightly less accurate. This is the G2MP2 method. Sometimes the geometry is obtained using a density functional theory method such as B3LYP and sometimes the QCISD(T) method in step 2 is replaced by the coupled cluster method CCSD(T).

  6. VSEPR theory - Wikipedia

    en.wikipedia.org/wiki/VSEPR_theory

    In effect, they considered nitrogen dioxide as an AX 2 E 0.5 molecule, with a geometry intermediate between NO + 2 and NO − 2. Similarly, chlorine dioxide (ClO 2) is an AX 2 E 1.5 molecule, with a geometry intermediate between ClO + 2 and ClO − 2. [citation needed] Finally, the methyl radical (CH 3) is predicted to be trigonal pyramidal ...

  7. Lattice constant - Wikipedia

    en.wikipedia.org/wiki/Lattice_constant

    Unit cell definition using parallelepiped with lengths a, b, c and angles between the sides given by α, β, γ [1]. A lattice constant or lattice parameter is one of the physical dimensions and angles that determine the geometry of the unit cells in a crystal lattice, and is proportional to the distance between atoms in the crystal.

  8. SN2 reaction - Wikipedia

    en.wikipedia.org/wiki/SN2_reaction

    The bimolecular nucleophilic substitution (S N 2) is a type of reaction mechanism that is common in organic chemistry. In the S N 2 reaction, a strong nucleophile forms a new bond to an sp 3 -hybridised carbon atom via a backside attack, all while the leaving group detaches from the reaction center in a concerted (i.e. simultaneous) fashion.

  9. Stoichiometry - Wikipedia

    en.wikipedia.org/wiki/Stoichiometry

    For example, in the reaction CH 4 + 2 O 2 → CO 2 + 2 H 2 O, the stoichiometric number of CH 4 is −1, the stoichiometric number of O 2 is −2, for CO 2 it would be +1 and for H 2 O it is +2. In more technically precise terms, the stoichiometric number in a chemical reaction system of the i-th component is defined as