 |
Reply
| | From:  Albert1145 (Original Message) | Sent: 4/14/2008 11:36 AM |
Hi Steve,
There are five questions that I'm not sure of the answers. And could you show me how to calculate the magnet moment because I don't think my tutor actually taught us how to do that?
Thank you Steve. |
|
 First
Previous
2-5 of 5
Next
Last
|
|
Reply
| | | From: ·Steve· | Sent: 4/14/2008 5:50 PM |
Hi Albert, I copied the questions here for easier reference. For examples of calculating the spin-only magnetic moment, see the examples at http://wwwchem.uwimona.edu.jm:1104/spectra/MagExamples.html. In the formula, μs.o. = √{4S(S+1)}, S is the total spin, or Σms where ms is the electron spin quantum number (+½ or –�?. It gives examples of the calculation in transition metal complexes with 1 unpaired electron, 2 unpaired electrons, etc.
I'll have to look at the rest of these tonight, but meantime, go ahead and post your answers so I can see how you are doing with these! What you need to determine is the number of unpaired electrons in each complex. This will depend on the charge of the transition metal and in some cases, the type of ligand field (octahedral, square planar, tetrahedral, etc.) and whether the complex is in the low spin or high spin configuration (which depends on whether the transition metal in is a weak crystal field or strong crystal field).
Steve
Q1- The spin only magnetic moment for the complex [V(H2O)6]2+ is (water - weak field ligand):
2.83 BM
4.90 BM
5.92 BM
1.73 BM
3.88 BM
Q2- How many unpaired electrons are there in the complex ion [Ni(H2O)6]2+? (water - weak field ligand)
1
2
3
4
5
Q3- The oxidation state of the central metal ion in the complex [Mn(CN)6]3�?/SUP> is:
3+
4+
6+
2+
5+
Q4- What is the coordination number about the metal ion for the complex [Co(NH3)4Cl2]Cl?
2
4
3
6
5
Q5- The oxidation state of the central metal ion in the complex ion [CoCl2(NH3)4]+ is:
5+
3+
6+
2+
4+
|
|
Reply
| |
Hi Steve,
I'll look at question one tonight when I get home because I think the web link is blocked by the uni internet, and for question 4, I'm not really sure what it meant by the 'coordination number'.
My answer to Q2- 2, Q3- 3+, Q5- 5.
Are they right?
Thank you |
|
Reply
| | | From: ·Steve· | Sent: 4/15/2008 5:55 AM |
Q1. To calculate the spin-only magnetic moment, you only need to know the number of unpaired electrons in the complex. In the case of V2+ ion, it is 3 (it is a d3 system). Next we must know the type of ligand field, which is octahedral is 6 water molecules are coordinating to the V2+ ion. The three unpaired electrons will be in the d-orbitals in the lower energy t2g set, one electron in each orbital. The spin-only magnetic moment, μs.o. , is, μs.o. = √[4S(S+1)] S is the sum of the spin quantum numbers of the unpaired electrons. If there are n unpaired electrons, then the sum will be n(½) = n/2. Putting n/2 in place of S in the equation gives, μs.o. = √[n(n + 2)] which is a simpler equation. The values of μs.o. from this equation are, n μs.o. 0 0 1 1.73 2 2.83 3 3.87 4 4.90 5 5.92 Q2.  The two unpaired electrons are in the higher energy eg set of d-orbitals. Q3. Q4. Four ammine ligands plus two chloro ligands, all monodentate, makes the coordination number 6 (octahedral). The other chloride ion is outside of the coordination sphere (not in the brackets [ ] ). Q5. Look again!  |
|
|
First
Previous
2-5 of 5
Next
Last
|
|
Free Forum Hosting
Important Announcement
Return to General