December 25, 2024, 10:16:12 AM
Forum Rules: Read This Before Posting


Topic: The nomenclature of coordination compounds  (Read 4074 times)

0 Members and 1 Guest are viewing this topic.

Offline emissivity

  • Regular Member
  • ***
  • Posts: 26
  • Mole Snacks: +1/-4
The nomenclature of coordination compounds
« on: October 06, 2013, 08:38:09 AM »
   Hi! I'm stuck in these problems so I've just come to ask you some favor..
well.. let's get started..

I've just tried to name these compounds. I'll show you the procedure of mine..
1. [Ag(NH3)2][Ag(CN)2]
First, left side is cation and the other side is anion. Next, each of them have +1, -1 charge(I think this procedure might have had my answer wrong). So, ammine has no charge at all,
diamminesilver(1) 
cyano has -1 charge so x-2=-1, x=1
dicyanoargentate(1)

thus its name is diamminesilver(1) dicyanoargentate(1)


2. [Pt(NH3)4)][Pt(Cl)4]
-> tetraammineplatinum(1) tetrachloroplatinate(3)


3. [Fe(NH3)6][Cr(CN)6]
-> hexaammineiron(1) hexacyanochromate(5)

Well.. However the answers were diamminesilver(I) dicyanoargentate(I), tetraammineplatinum(II) tetrachloroplatinate(II), hexaammineiron(III) hexacyanochromate (III) in order. I think it was the main problem that I assigned each anion and cation +1, -1. How can I overcome this problem? Please help me!



====
The first one was right. But the others were wrong though I have solved them in same way.

Offline Schrödinger

  • Chemist
  • Sr. Member
  • *
  • Posts: 1162
  • Mole Snacks: +138/-98
  • Gender: Male
Re: The nomenclature of coordination compounds
« Reply #1 on: October 06, 2013, 09:36:51 AM »
The problem is that you're starting off by assigning +1 oxidation state to the leftmost metal. This is not how it works, since it's not an algorithm that men have devised. These are common oxidation states found in nature.

You need to be able to read off data from the periodic table given the compounds. For instance, Fe(I) is not a common oxidation state. The most common ones for Fe are +2 and +3. And for Cr coordinated in an octahedral fashion, the most common oxidation state is +3, which gives rise to the d3 configuration.

Take the case of Pt. The most common oxidation states are +2, +4. +1 and +3 are, as far as I know, non-existent (although if they do exist, they must be very rare)

I would suggest familiarizing yourself with common oxidation states. You should be able to find this in any inorganic text.
"Destiny is not a matter of chance; but a matter of choice. It is not a thing to be waited for; it is a thing to be achieved."
- William Jennings Bryan

Offline emissivity

  • Regular Member
  • ***
  • Posts: 26
  • Mole Snacks: +1/-4
Re: The nomenclature of coordination compounds
« Reply #2 on: October 08, 2013, 09:22:43 AM »
Thank you, Schrödinger.
As you have already said that, I might have to get used to common oxidation states.

Thank you again!

Sponsored Links