Home > Uncategorized > Introduction to Solid State Chemistry Lecture 9

Introduction to Solid State Chemistry Lecture 9

Overview
Today’s lecture is 51 minutes long.

Details
The Madelung constant tells us the energy gain if we pack atoms into a 3D structure.

Octet stability via electron transfer.

Lewis in 1916 posited that octets could be filled by electron sharing. Electrons may be divided into bonding domains and non-bonding domains.

Bond formation comes from cooperative use of valence electrons or covalent bonds. Ionic bonds from electron transfer, covalent bonds from electron sharing.

Sulfuryl chloride is SO2Cl2. O=S=O with the clorines up and below. When both electrons come from one element, its a dative bond. That was the case for the O=S bond.

Pauling – let’s mix the orbitals; ie hybrid orbitals in order to maximize the number of bonds and minimize the energy. s2 p6 turn into sp3.

H-H bond is 435 kJ/mol
F-F is 160
H-F is 569
Electrons are not shared equally. In fact the electrons are drawn to the flourine. Charge displacement is stored energy. Neteronuclear bonds are formed by share and pull.

The degree of unequal sharing is electronegativity.
EN = sqrt(Ehh.Eff) + 96.3(Xh-Xf)^2 kJ/mol

For HF, 264 + 344 = 608 but the real value is 569.

One term is purely sharing term, another term is the ionic term.

A capacitor is just a bunch of aligned dipoles. More energy per electric field.

0-100 % ionic character
]1-exp(-.25(difference in ENs))^2] x 100

Freon is CF2Cl2. In the atmosphere, the reaction that occurs is: Cl2 + O3 = ClO + O2-

Review
Tissue: nerve, muscle, connective, epithelial

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