.. _sphx_glr_api_gallery_structure_vsepr:

VSEPR geometry prediction
--------------------------

Steric number and lone-pair count to idealized 3D molecular geometry,
via real electron-domain coordinate generation -- not a shape-name
lookup table.


.. raw:: html

  <div id='sg-tag-list' class='sphx-glr-tag-list'></div>


.. raw:: html

    <div class="sphx-glr-thumbnails">

.. thumbnail-parent-div-open

.. raw:: html

    <div class="sphx-glr-thumbcontainer" tooltip="Builds four molecules spanning the five idealized electron-domain polyhedra -- methane (AX4E0, tetrahedral), water (AX2E2, bent from a tetrahedral parent), sulfur tetrafluoride (AX4E1, seesaw from a trigonal bipyramidal parent), and xenon tetrafluoride (AX4E2, square planar from an octahedral parent) -- via build_vsepr_molecule, and verifies the exact idealized bond angles each shape predicts.">

.. only:: html

  .. image:: /api/gallery/structure/vsepr/images/thumb/sphx_glr_plot_01_vsepr_geometries_thumb.png
    :alt:

  :doc:`/api/gallery/structure/vsepr/plot_01_vsepr_geometries`

.. raw:: html

      <div class="sphx-glr-thumbnail-title">VSEPR geometry prediction: from steric number to real 3D coordinates</div>
    </div>


.. raw:: html

    <div class="sphx-glr-thumbcontainer" tooltip="Jacobus van&#x27;t Hoff and Joseph Le Bel independently proposed in 1874 that a carbon atom&#x27;s four bonds point toward the vertices of a regular tetrahedron -- and that a carbon bonded to four different substituents therefore has no internal mirror symmetry: its mirror image cannot be superimposed on itself by any rotation, giving two distinct, non- interconvertible molecules (enantiomers). This builds a genuinely tetrahedral AX4 center -- bromochlorofluoromethane, CHFClBr, the textbook minimal chiral carbon -- from domain_positions&#x27;s real 3D vertex coordinates, confirms the exact 109.47-degree bond angles van&#x27;t Hoff and Le Bel&#x27;s model predicts, and then demonstrates the chirality itself numerically: a scalar-triple-product handedness invariant flips sign under reflection but is exactly preserved under any proper rotation (built with rotation_matrix), so no rotation can ever turn the molecule into its own mirror image.">

.. only:: html

  .. image:: /api/gallery/structure/vsepr/images/thumb/sphx_glr_plot_02_tetrahedral_chirality_thumb.png
    :alt:

  :doc:`/api/gallery/structure/vsepr/plot_02_tetrahedral_chirality`

.. raw:: html

      <div class="sphx-glr-thumbnail-title">Van't Hoff and Le Bel's tetrahedral carbon: chirality from real 3D coordinates</div>
    </div>


.. raw:: html

    <div class="sphx-glr-thumbcontainer" tooltip="James Musher (1969) grouped molecules such as \mathrm{PCl_5}, \mathrm{SF_6}, \mathrm{ClF_3} and the xenon fluorides into one class: hypervalent molecules, whose central main-group atom appears to hold more than the eight electrons of Lewis&#x27;s octet. Counting the Lewis electrons around the central atom (two per bond plus two per lone pair) gives 10 or 12 for all of them.">

.. only:: html

  .. image:: /api/gallery/structure/vsepr/images/thumb/sphx_glr_plot_03_hypervalent_molecules_thumb.png
    :alt:

  :doc:`/api/gallery/structure/vsepr/plot_03_hypervalent_molecules`

.. raw:: html

      <div class="sphx-glr-thumbnail-title">Musher's hypervalent molecules: main-group centres beyond the octet</div>
    </div>


.. thumbnail-parent-div-close

.. raw:: html

    </div>


.. toctree::
   :hidden:

   /api/gallery/structure/vsepr/plot_01_vsepr_geometries
   /api/gallery/structure/vsepr/plot_02_tetrahedral_chirality
   /api/gallery/structure/vsepr/plot_03_hypervalent_molecules