# Naming coordination compound

• Chemistry
• jolly_math
In summary, XPS can be used to infer that there will be different oxidation states, while ESR can be used to determine the exact oxidation state.

#### jolly_math

Homework Statement
Name the following coordination compound:
[Pt(NH3)4I2][PtI4]
Relevant Equations
oxidation state
I know that the compound is tetraamminediiodoplatinum tetraiodoplatinate. To make the compound neutral, I find there are several possibilities of the platinum ion oxidation state in the complex cation and anion(3 and 3, 4 and 2, etc.) How would I be able to determine the oxidation state? Thank you.

How do you work out that there will be different oxidation states? Please show your work so we can follow your reasoning.

TeethWhitener said:
How do you work out that there will be different oxidation states? Please show your work so we can follow your reasoning.
I'm representing the charge of Pt as [Pt](1st or 2nd)
[Pt(NH3)4I2]: overall charge is [Pt](1st) - 2
[PtI4]: overall charge is [Pt](2nd) - 4
I want to find charge of Pt so that [Pt] - 2 + [Pt] - 4 = [Pt](1st) + [Pt](2nd) + 6 = 0,
possibilities are 3 + 3, 4 + 2, etc.

jolly_math said:
I'm representing the charge of Pt as [Pt](1st or 2nd)
[Pt(NH3)4I2]: overall charge is [Pt](1st) - 2
[PtI4]: overall charge is [Pt](2nd) - 4
I want to find charge of Pt so that [Pt] - 2 + [Pt] - 4 = [Pt](1st) + [Pt](2nd) + 6 = 0,
possibilities are 3 + 3, 4 + 2, etc.
I see. Unfortunately, there’s no way to figure it out by analyzing formal charges alone. You also need to know that Pt(IV) is the highest oxidation state you’ll see without going to heroic efforts, and also that Pt(III) is an incredibly rare oxidation state (I can’t think of a single example, but there might be some in the literature). Also, Pt(I) is a weird oxidation state that likely requires Pt-Pt bonding. All this is knowledge that you wouldn’t be able to glean from the chemical formula, but suffice it to say that if you’re working with platinum, the only oxidation states you’ll likely be dealing with are +2 and +4.

jolly_math
Also: don't treat oxidation states too religiously, especially in more complicated compounds, especially transition metal complexes. Apart from some very simple cases there is no physical property that we can measure to check what the oxidation state of an atom is. In molecules electrons are on molecular orbitals and are not assigned to any particular atom. Actually we can assign these numbers a bit at random, as long they produce decent logic. Your compound is a good example: no matter what oxidation states of both Pt atoms are, the only thing that really matters is that the overall charge is zero. Sure, we do expect them to have "reasonable" values, but it is not worth to dig too deep, as there is no sound logic that can be applied.

jolly_math, Bystander and TeethWhitener

## 1. What is a coordination compound?

A coordination compound is a type of molecule that contains a central metal atom or ion surrounded by a group of atoms or molecules called ligands. The ligands are attached to the metal atom or ion through coordinate covalent bonds.

## 2. How do you name a coordination compound?

The name of a coordination compound is determined by following a set of rules based on the type and number of ligands attached to the central metal atom or ion. The name will include the names of the ligands, followed by the name of the central metal atom or ion, and may also include any necessary prefixes or suffixes to indicate the oxidation state of the metal atom or ion.

## 3. What is the difference between a cation and an anion in coordination compounds?

A cation is a positively charged ion that is attracted to the negatively charged ligands in a coordination compound. An anion is a negatively charged ion that is attracted to the positively charged central metal atom or ion in a coordination compound.

## 4. How do you determine the oxidation state of a central metal atom or ion in a coordination compound?

The oxidation state of a central metal atom or ion in a coordination compound can be determined by considering the overall charge of the compound and the charges of the ligands. The sum of the charges must equal the overall charge of the compound, so the oxidation state of the central metal atom or ion can be calculated by subtracting the charges of the ligands from the overall charge.

## 5. Can coordination compounds have multiple names?

Yes, coordination compounds can have multiple names depending on the rules used to name them. For example, a coordination compound can have a common name, a systematic name, and a chemical name. It is important to use the correct naming convention when referring to a specific coordination compound.