The complex `Na_(2)[Fe(CN)_(5)NO]` is called :

Options

A. sodium pentacyanonitrosoniumferrate (II)
B. sodium nitroprusside
C. sodium pentacyanonitrosylferrate (III)
D. sodium nitrosoferrocyanide

Answer

To determine the name of the complex \( \text{Na}_2[\text{Fe}(\text{CN})_5\text{NO}] \), we can follow these steps:

### Step 1: Identify the components of the complex
The complex consists of:
- Sodium ions (\( \text{Na}^+ \))
- A central metal ion, which is iron (\( \text{Fe} \))
- Ligands, which include five cyanide ions (\( \text{CN}^- \)) and one nitrosyl ligand (\( \text{NO} \))

### Step 2: Determine the oxidation state of the central metal ion
To find the oxidation state of iron in the complex, we can set up the equation based on the overall charge of the complex:
- The complex ion \( [\text{Fe}(\text{CN})_5\text{NO}] \) is neutral, and the sodium ions contribute a charge of \( +2 \) (since there are two sodium ions).
- The cyanide ion (\( \text{CN}^- \)) has a charge of \( -1 \), and there are five of them, contributing \( -5 \).
- The nitrosyl ligand (\( \text{NO} \)) is neutral in this case.

Let \( x \) be the oxidation state of iron (\( \text{Fe} \)):
\[ x + (5 \times -1) + 0 = 0 \\ x - 5 = 0 \\ x = +5 \]

### Step 3: Naming the ligands
- The cyanide ligand is named "cyano" and since there are five of them, we use the prefix "penta" to indicate five. Therefore, it is "pentacyano".
- The nitrosyl ligand (\( \text{NO} \)) is named "nitrosyl".

### Step 4: Naming the metal and its oxidation state
- The metal iron in this complex is in the +5 oxidation state. According to IUPAC nomenclature, we denote the oxidation state of the metal in Roman numerals in parentheses after the name of the metal. Thus, iron in +5 oxidation state is called "ferrate(V)".

### Step 5: Combine all parts to form the complete name
Putting it all together, we have:
- Cation: Sodium (2 sodium ions)
- Ligands: Pentacyano and nitrosyl
- Metal: Ferrate(V)

The complete name of the complex is:
**Sodium pentacyanonitrosylferrate(V)**

### Final Answer:
The complex \( \text{Na}_2[\text{Fe}(\text{CN})_5\text{NO}] \) is called **Sodium pentacyanonitrosylferrate(V)**.

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