Write the formula for a complex formed between Ni 2+ and NH3, with a coordination number of 5.
Write the formula for a complex formed between Ni 2+ and CN–, with a coordination number of 4.
I am having trouble with these problem because I don't really understand what coordination numbers are. I know that Ni is 2+ and I believe that NH3 is 1-, but I don't understand how to make the coordination number 5.
Thank you so much.
Coordination number has slightly different meanings depending upon how it is used. One is in crystallography and the other is in complex formation. Here is a site that you can read about both.
http://en.wikipedia.org/wiki/Coordination_number
Basically, coordination number in complex ion formation is the number of atoms bound to the central atom. So if you want Ni^2+ and CN^- with coordination number of 4 you write [Ni(CN)4]^2- . The 2- charge is figures just like oxidation numbers; i.e., Ni ion is ^2+ and 4 CN ions at -1 each is -4. Then +2 + (-4) = -2.
You're right that Ni^2+ is 2+ but NH3 is zero. All compounds are neutral; Ni is 2+ because that's the charge on the ion.
Rearrange this equation to isolate a
b
(a+ c) (d-e)=f
What is the formula of the compound formed between the ions CO32- and Ni2+
Well, coordination numbers are like the number of guests at a party that a central atom (like Ni 2+) can accommodate. Just like you can have different people with different roles and positions at a party, a central atom can form complexes with different ligands (like NH3 or CN–) surrounding it.
For the complex formed between Ni 2+ and NH3, with a coordination number of 5, we need to make sure the overall charge is balanced. Since Ni is 2+ and each NH3 molecule is neutral, we need a total of two NH3 ligands to neutralize the charge of Ni. So, the formula for this complex is [Ni(NH3)2]2+.
Now, for the complex formed between Ni 2+ and CN–, with a coordination number of 4, we similarly balance the charges. Since Ni is 2+ and CN– has a charge of 1–, we only need two CN– ligands to neutralize the charge of Ni. Therefore, the formula for this complex is [Ni(CN)2]2+.
I hope this explanation didn't leave you feeling too complexed! If you need any more assistance, feel free to ask!
No problem! I'm here to help you understand coordination numbers and solve these complex formation problems.
In coordination chemistry, coordination number refers to the number of coordination bonds formed between a central metal ion and its surrounding ligands. Ligands are molecules or ions that donate a pair of electrons to the metal ion.
Let's start with the first problem. You are given that the metal ion is Ni 2+ (nickel with a 2+ charge). To form a complex with a coordination number of 5, the nickel ion must be surrounded by 5 ligands. In this case, the ligand is NH3, which is ammonia.
Ammonia, NH3, is a neutral ligand. Each ammonia molecule can donate a pair of electrons to the nickel ion, forming a coordination bond. Since you need 5 ammonia ligands, the formula for the complex would be Ni(NH3)5^2+.
Next, let's move on to the second problem. You are given that the metal ion is still Ni 2+, but the ligand is CN– (cyanide ion). To form a complex with a coordination number of 4, the nickel ion must be surrounded by 4 ligands.
CN– is a negatively charged ligand with a charge of -1. Therefore, to balance the charges, two cyanide ions are required to form a coordination bond with the nickel ion. The formula for the complex would then be Ni(CN)2^2-.
In summary, the formulas for the complexes you are asked to write are:
1. Ni(NH3)5^2+ - complex formed between Ni 2+ and NH3 with a coordination number of 5.
2. Ni(CN)2^2- - complex formed between Ni 2+ and CN– with a coordination number of 4.
I hope this explanation helps you understand coordination numbers better and how to solve these types of problems. If you have any further questions, feel free to ask!