IUPAC name of `Li[AIH_(4)]` is

Options

A. Lithium aluminium hydride
B. Lithium tetrahydrido aluminate (III)
C. Tetrahydride aluminium lithionate
D. Aluminium lithium hydride

Explanation

To find the IUPAC name of the compound `Li[AlH₄]`, we can follow these steps:

### Step 1: Identify the components of the compound
The compound consists of lithium (Li) and a coordination complex `[AlH₄]`. In the complex, aluminum (Al) is the central metal atom, and there are four hydride (H⁻) ligands surrounding it.

### Step 2: Name the cation
The cation in this compound is lithium. In IUPAC nomenclature, we simply write "lithium".

### Step 3: Identify and name the ligands
The ligands in the coordination complex are hydride ions (H⁻). Since there are four hydride ligands, we use the prefix "tetra-" to indicate the number. The name of the hydride ligand in coordination chemistry is "hydrido". Therefore, we write "tetrahydrido" for the four hydride ligands.

### Step 4: Name the central metal
The central metal in the complex is aluminum (Al). In coordination compounds, if the metal is in a positive oxidation state, we simply use its name. However, since the overall charge of the complex is negative, we need to modify the name of aluminum to reflect this. The correct modification is to use "aluminate" for aluminum in a negatively charged complex.

### Step 5: Determine the oxidation state of the metal
To find the oxidation state of aluminum in this complex, we consider the charges:
- Lithium has a +1 charge.
- Each hydride has a -1 charge, and there are four of them, contributing a total of -4 charge.

To balance the charges:
- Let the oxidation state of aluminum be \( x \).
- The total charge of the complex is \( +1 + x - 4 = 0 \).
- Solving for \( x \) gives us \( x = +3 \).

### Step 6: Combine the names
Now we can combine the names we have found:
- Cation: lithium
- Ligands: tetrahydrido
- Anion: aluminate (with the oxidation state indicated as 3)

Putting it all together, the IUPAC name of the compound `Li[AlH₄]` is:
**Lithium tetrahydridoaluminate(III)**.

### Final Answer:
**Lithium tetrahydridoaluminate(III)**

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