Structure Names

[Emily_Stenzler_2H]

I'm guessing I missed this in lecture, but can someone explain why the octahedral structure is called octahedral when it has 6 bonds rather than 8? I am also a bit confused as to how the bipyramidal structures got their names- is it just because they have two 'points'?

If someone can explain the logic behind the structure names I would greatly appreciate it!

[abby hyman]

The reason that a molecule with 6 electron regions has an octahedral geometry is that the shape that is made in which the atoms would be the most stable is called an octahedron. This shape has 6 vertices which would represent the positions of the 6 electron regions.
As for trigonal bipyramidal, a molecule with this shape would have 5 bound atoms and the way I think of it is that 3 atoms are arranged in a flat triangle and then the fourth and fifth atoms would be above and below the triangle which would form a top trigonal pyramid and a bottom trigonal pyramid.

[Eliana Witham 2H]

For octahedral, when you create a shape out of the atoms, making each one a vertex, then you get an octahedron. This shape has 8 faces, hence the name. If you look up the shape online, it will make more sense!

[Michael Cardenas 3B]

The reason that the shape of a molecule with 6 bonding regions is called octahedral is because the most stable shape for this molecule is an octahedron which has 8 faces.

[Bai Rong Lin 2K]

I'm guessing I missed this in lecture, but can someone explain why the octahedral structure is called octahedral when it has 6 bonds rather than 8? I am also a bit confused as to how the bipyramidal structures got their names- is it just because they have two 'points'?

If someone can explain the logic behind the structure names I would greatly appreciate it!

There is 6 bonding region which results in 8 faces hence the name!

[Joshua Chung 2D]

Octahedral structures are formed when 6 bonds orient regularly around a central atom, forming a structure with 8 faces (thus lending the name "octahedron"). I think of bipyramidal structures as two pyramids sharing a base, forming a shape similar to the green thing from Sims.