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Topic: Some problems in Inorganic chemistry and I need help ..  (Read 2655 times)

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Offline anita

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Some problems in Inorganic chemistry and I need help ..
« on: October 03, 2011, 09:33:28 PM »
I want solve for this problems


1.    Determine the two values of r where the RDF of a 3pz orbital has maxima.

2.    Prove that the electron probability function for a ground state P atom has spherical symmetry, i.e. show that the sum of a px, py and pz orbital has no angular dependence.

3a.   Madelung constants can be derived by calculating a summation of coulombic interactions, each term in the series indicates all the interactions for a specific ion-ion distance.  For each coulombic contribution, the sign (from anion or cation), the total number of interactions, and interaction distance needs to be determined.  The lecture notes show a simple example for the infinite linear chain.

3b. Derive the first 30 terms (arising from 30 shortest distances) for determining the Madelung constant of CsCl.  For each term, indicate the number of interactions, the sign, and the distance in terms of the lattice parameter a.  To accomplish this, apply symmetry and permutations to (xyz) coordinates, and use a spreadsheet. Do not try to use drawings or models.

4.     After solving the above problem, what can you conclude about the convergence of the Madeling constant. Are 30 terms sufficient to determine which structures are most stable in terms of lattice enthalpy? Why or why not?

Offline iaminyourclass

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Re: Some problems in Inorganic chemistry and I need help ..
« Reply #1 on: October 06, 2011, 08:15:15 PM »
1. Take the derivative of the 3pz function and set it equal to 0.  You will get 4 answers.  Two are minimums two are maxima.

2. Take the angular portion of the three functions and multiply each one by their complex conjugate, then sum them up.  The angular portion becomes a constant and is therefore independent of theta and phi.

3. Read this paper from the computers on campus.  http://pubs.acs.org/doi/abs/10.1021/ed078p1198

4. Once you answer 3 this will become evident.

I am in your class, you can ask us.  But you'll have to squawk like a chicken so I know you are you. 

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