The IUPAC name of `K_(4)[Ni(CN)_(4)]` is

Options

A. Tetrapotassium tetracyano nickelate (II)
B. Potassium tetracyano nickel (II)
C. Potassium tetracyano nickelate ( 0)
D. Potassium tetracyano nickelate (II)

Answer

To determine the IUPAC name of the complex compound \( K_4[Ni(CN)_4] \), we can follow these steps:

### Step 1: Identify the Cation and Anion
The compound consists of a cation and an anion. The cation is \( K^+ \) (potassium) and the anion is the complex ion \( [Ni(CN)_4]^{4-} \).

### Step 2: Name the Cation
The cation is potassium. In IUPAC nomenclature, we simply write "potassium" without any prefixes indicating the number of potassium ions present (even though there are four).

**Hint:** When naming cations, only the name of the cation is used without any numerical prefixes.

### Step 3: Name the Anionic Complex
The anionic part is the complex ion \( [Ni(CN)_4]^{4-} \).

- **Identify the Ligand:** The ligand here is cyanide, which is denoted as "cyano" in IUPAC nomenclature. Since there are four cyanide ligands, we use the prefix "tetra" to indicate this.

- **Identify the Central Metal Atom:** The central metal atom is nickel (Ni).

- **Determine the Oxidation State of the Metal:** The overall charge of the complex ion is -4. Since each cyanide ligand has a charge of -1 and there are four of them, the total negative charge contributed by the ligands is -4. Therefore, the oxidation state of nickel in this complex is 0 (since \( x + (-4) = -4 \) leads to \( x = 0 \)).

- **Name the Metal with Appropriate Suffix:** Since the oxidation state of nickel is 0, we use the suffix "-ate" to denote that it is part of an anionic complex. Thus, nickel becomes "nickelate".

**Hint:** When naming ligands, use the appropriate prefixes for the number of ligands and remember to change the metal name to reflect its oxidation state when it is part of an anionic complex.

### Step 4: Combine the Names
Now we can combine the names of the cation and the anionic complex. The full name will be:

**Final IUPAC Name:** Potassium tetracyanonickelate(0)

### Summary
The IUPAC name of \( K_4[Ni(CN)_4] \) is **Potassium tetracyanonickelate(0)**.