How to Calculate Number of Metal-Metal Bonds and Number of Bonds per Atom
Number of M-M Bonds & Number of Bonds per Atom Calculator
Total number of valence electrons (X) in the complex = Number of valence electrons in the metal + Electrons from each ligand + Charge (use table).
Find out number of Metals in Complex (N)
Now, the number of M-M bonds in Complex = [N × 18) − X] ÷ 2
Now, number of Bond per Atom = 18 − (X/N)
Note: 'X' divided by 'N' gives the number of electrons per metal atom. If this number comes out to be 18 it implies there are no metal-metal bonds; for 17, there will be one M-M bond and if it is 16, there will be two M-M bonds and so on.
The Mo−Mo bond order in [(η5- C5H5)Mo(CO)2]2 which obeys the 18- electron rule is GATE: 2021
Answer: Total Valence Electron (X) = (5 × 2) + (6 × 2) + (4 × 2) = 30
Number of Metals in Complex (N) = 2
Now, the number of M-M bonds in Complex = [N × 18) − X] ÷ 2
or, Mo−Mo bond order in [(η5- C5H5)Mo(CO)2]2 = (2 × 18) − 30] ÷ 2 = 3
The number of metal-metal bonds in [Mo2(CH3CO2)4] complex is GATE: 2022
Answer: Total Valence Electron (X) = (6 × 2) + (4 × 4) = 28
Number of Metals in Complex (N) = 2
Now, the number of M-M bonds in Complex = [N × 18) − X] ÷ 2
or, Number of Mo−Mo bonds in [Mo2(CH3CO2)4] = (2 × 18) − 28] ÷ 2 = 4
The number of metal-metal bonds in [Co2Fe2(CO)11(µ4-PPh)2] is CSIR:NET/JRF: June 2016
Answer: Total Valence Electron (X) = 14 + 16 + 22 + 8 = 64
Number of Metals in Complex (N) = 4
So, the Number of M−M bonds in [Co2Fe2(CO)11(µ4-PPh)2] = (4 × 18) − 64] ÷ 2 = 4
The W-W bond order in [W(n5-C5H5)(µ-Cl)(CO)2]2 is CSIR:NET/JRF: Dec. 2015
Answer: Total Valence Electron (X) = 12 + 10 + 6 + 8 = 36
Number of Metals in Complex (N) = 2
So, the Number of M−M bonds in [W(n5-C5H5)(µ-Cl)(CO)2]2 = (2 × 18) − 36] ÷ 2 = 0
The number of metal-metal bonds in [Ni2(CO)6]2- that are consistent with 18 electron rule respectively are CSIR:NET/JRF: June 2014
Answer: Total Valence Electron (X) = 20 + 12 + 2 = 34
Number of Metals in Complex (N) = 2
So, the Number of M−M bonds in [Ni2(CO)6]2- = (2 × 18) − 34] ÷ 2 = 1
The number of metal-metal bonds in [Ir4(CO)12] is CSIR:NET/JRF: June 2013
Answer: Total Valence Electron (X) = 36 + 24 = 60
Number of Metals in Complex (N) = 4
So, the Number of M−M bonds in [Ir4(CO)12] = (4 × 18) − 60] ÷ 2 = 6
The number of metal-metal bonds in [W2(OPh)6] is CSIR:NET/JRF: June 2013
Answer: Total Valence Electron (X) = 12 + 18 = 30
Number of Metals in Complex (N) = 2
So, the Number of M−M bonds in [W2(OPh)6] = (2 × 18) − 30] ÷ 2 = 3
In the cluster [Co3(CH)(CO)9] obeying 18 electron rule, the number of metal-metal bonds are CSIR:NET/JRF: Dec. 2012
Answer: Total Valence Electron (X) = (3 × 9) + 2 + (9 × 2) = 27 + 2 + 18 = 47
Number of Metals in Complex (N) = 3
So, the Number of M−M bonds in [Co3(CH)(CO)9] = (3 × 18) − 47] ÷ 2 = 3.5 (Considered as 3)
The number of metal-metal bonds in the dimers, [CpFe(CO)(NO)]2 and [CpMo(CO)3]2 respectively are CSIR:NET/JRF: Dec. 2011
Answer:
[CpFe(CO)(NO)]2 Complex:
Total Valence Electron (X) = [5 + 8 + 2 + 3] × 2 = 18 × 2 = 36
Number of Metals in Complex (N) = 2
So, the Number of M−M bonds in [CpFe(CO)(NO)]2 = (2 × 18) − 36] ÷ 2 = 0
[CpMo(CO)3]2 Complex:
Total Valence Electron (X) = [5 + 6 + (2 × 3)] × 2 = 17 × 2 = 34
Number of Metals in Complex (N) = 2
So, the Number of M−M bonds in [CpMo(CO)3]2 = (2 × 18) − 34] ÷ 2 = 1
Calculate the number of metal meta bonds in the following complexes:
1. [Fe2(CO)4]2-
2. [Co3(CH)(CO)9]
3. [Ni2(CO)6]2+
4. [(η5-C5H5)Fe(CO)]2
5. [Ru2Cl4(CO)4]
6. [Ag4(CN)4]
7. [Cr2O7]2-
8. [Mn2(CO)10]
9. dimer [Mn2(CO)10]
10. [Ru3(CO)12]
11. [Ti2Cl8]2-
12. [Fe(CO)(PPh3)]2
13. [Co4(CO)(C5H5)]4
14. [V2O5]
| Answer | ||||||
|---|---|---|---|---|---|---|
| 1- 1 | 2- 0 | 3- 2 | 4- 0 | 5- 2 | 6- 3 | 7- 0 |
| 8- 1 | 9- 1 | 10- 3 | 11- 2 | 12- 0 | 13- 4 | 14- 0 |
Electrons Donated by Various Ligands
