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  2. VSEPR theory - Wikipedia

    en.wikipedia.org/wiki/VSEPR_theory

    [1]: 410–417 The total number of X and E is known as the steric number. For example in a molecule AX 3 E 2, the atom A has a steric number of 5. When the substituent (X) atoms are not all the same, the geometry is still approximately valid, but the bond angles may be slightly different from the ones where all the outside atoms are the same.

  3. Seesaw molecular geometry - Wikipedia

    en.wikipedia.org/wiki/Seesaw_molecular_geometry

    The seesaw geometry occurs when a molecule has a steric number of 5, with the central atom being bonded to 4 other atoms and 1 lone pair (AX 4 E 1 in AXE notation). An atom bonded to 5 other atoms (and no lone pairs) forms a trigonal bipyramid with two axial and three equatorial positions, but in the seesaw geometry one of the atoms is replaced ...

  4. Steric effects - Wikipedia

    en.wikipedia.org/wiki/Steric_effects

    Regioselective dimethoxytritylation of the primary 5'-hydroxyl group of thymidine in the presence of a free secondary 3'-hydroxy group as a result of steric hindrance due to the dimethoxytrityl group and the ribose ring (Py = pyridine). [2] Steric hindrance is a consequence of steric effects. Steric hindrance is the slowing of chemical ...

  5. Molecular geometry - Wikipedia

    en.wikipedia.org/wiki/Molecular_geometry

    This constraint removes one degree of freedom from the choices of (originally) six free bond angles to leave only five choices of bond angles. (The angles θ 11, θ 22, θ 33, and θ 44 are always zero and that this relationship can be modified for a different number of peripheral atoms by expanding/contracting the square matrix.)

  6. Stereocenter - Wikipedia

    en.wikipedia.org/wiki/Stereocenter

    The number of hypothetical stereoisomers can be ... stereocenters can have either sp 3 or sp 2 hybridization. ... certain configurations may not exist due to steric ...

  7. Trigonal pyramidal molecular geometry - Wikipedia

    en.wikipedia.org/wiki/Trigonal_pyramidal...

    The nitrogen in ammonia has 5 valence electrons and bonds with three hydrogen atoms to complete the octet.This would result in the geometry of a regular tetrahedron with each bond angle equal to arccos(− ⁠ 1 / 3 ⁠) ≈ 109.5°.

  8. Square pyramidal molecular geometry - Wikipedia

    en.wikipedia.org/wiki/Square_pyramidal_molecular...

    Structure of xenon oxytetrafluoride, an example of a molecule with the square pyramidal coordination geometry.. Square pyramidal geometry describes the shape of certain chemical compounds with the formula ML 5 where L is a ligand.

  9. 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 ...