Home > Uncategorized > Introduction to Solid State Chemistry Lecture 8: Energetics and Ion Pair Attraction

Introduction to Solid State Chemistry Lecture 8: Energetics and Ion Pair Attraction

Overview
This class costs 51 minutes. We are slowly drifting into chemistry now.

Details
electron donor + electron acceptor = cation + anion

Coulombic attraction leads to ionic bonding.

NaCl = Na+ + Cl-
Sodium is the electron donor, chlorine is the electron acceptor.

He goes through the Eo versus r graph. Ro is the interionic seperation from nucleus to nucleus. Sodium ion at the origin. Hard shell models have no shrinkage when the two atoms touch.

E attractive = q1q2/4piEor

Sodium has 11 protons and 11 electrons. At Na+, there are 10 electrons.

“For grins and chuckles…”

Energy is decreasing as we move to the left, then reaches a peak and increases quickly.

E repulsion = b/(r^n) where n is the Born exponent, experimentally derived, from 6 to 12. You basically add the two curves, the attractive and repulsive. A minimum is reached when the ions are touching, then energy increases.

E ro = z+z-/4piEoRo(1-1/n) The ionic bond is ES attraction mediated by ER.

Ionic bonds have E fields that are omni directional. Unsaturated bonds mean that you may bond with other ions at the same time. Infinite atomic ordered arrays – crystals. Solids at room temperature.

E ion dispersion = N avagadro E(ro)

E = -M Nav e2/4pi EoRo (1-1/n)

Ionic Crystals: solid at room temperature, high MP and BP, transparent to visible light, electrical insulators, hard and brittle, soluble in polar solvents, melt to form ionic liquids

The energy change in a chemical reaction is path independent.

Hess’s Law
Na(s) + 1/2 Cl2(g)=NaCl(s,xtl)

Enthalpy=energy for condensed mater

When things crystalllize, alot of heat is given off.

Aluminum Production
2Al3+ + 6e-=2Al
3O2- + 1.5C=1.5CO2 + 6e-
So, 2Al3+ + 3O2- + 1.5C=2Al + 1.5CO2
For every ton of aluminum we make, we must give off 1/2 ton of carbon. This is bad for the environment. The teacher’s research is interested in an inert anode like O2 that would generate no GHGs.

Review
11ev>, metal and a electron donor. 13eV<, nonmetal and a electron acceptor.

Liquid: Hg, Br, Fr, Cs Ga, Rb

Pressure=dgh

HRT hostage rescue team

The American Drill: bellybutton to midthigh

Advertisements
Categories: Uncategorized
  1. No comments yet.
  1. No trackbacks yet.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: