Expanded Octets

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Megan Purl 1E
Posts: 49
Joined: Fri Sep 29, 2017 7:07 am

Expanded Octets

Postby Megan Purl 1E » Sun Nov 05, 2017 4:46 pm

How can you tell if a molecule will have an expanded octet or not when drawing the Lewis structures?

Suchita 2I
Posts: 59
Joined: Fri Sep 29, 2017 7:04 am

Re: Expanded Octets

Postby Suchita 2I » Sun Nov 05, 2017 4:57 pm

Elements from Period 3 and higher can have an expanded octet due to the d orbitals which can accommodate more electrons, but generally look out for Phosphorus and Sulfur, as in PCl5 and SF6.

Ryan Sydney Beyer 2B
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Re: Expanded Octets

Postby Ryan Sydney Beyer 2B » Sun Nov 05, 2017 5:13 pm

Main group elements that form more bonds than what would be predicted by the normal octet rule are called hypervalent compounds. These compounds have an expanded octet meaning that there are more than eight electrons around one atom. The octet can be expanded by some elements by utilizing the empty d - orbitals found in the third principal energy level and beyond. Sulfur, phosphorous,and chlorine are common examples that have an expanded octet. You can tell that a molecule might have an atom with an expanded octet if (1) the element is capable of accessing the d - orbital and if (2) the atom is more stable with a lower overall formal charge if an element that has access to the d - orbitals is surrounded by more than 8 electrons.


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