Which of the following is the electron-deficient molecule?

Options

A. `C_(2)H_(6)`
B. `SiH_(4)`
C. `SnCl_(4)`
D. `B_(2)H_(6)`

Explanation

To determine which of the given molecules is electron-deficient, we need to analyze the electron configuration and bonding of each molecule. Let's go through the options step by step:

### Step 1: Analyze C2H6 (Ethane)
- Ethane consists of two carbon atoms and six hydrogen atoms.
- Each carbon atom has 4 valence electrons.
- In C2H6, each carbon is bonded to three hydrogens, which provides a total of 8 electrons for each carbon (4 from the carbon and 1 from each hydrogen).
- Therefore, the octet for both carbon atoms is complete.

**Conclusion:** C2H6 is not electron-deficient.

### Step 2: Analyze SiH4 (Silane)
- Silane consists of one silicon atom and four hydrogen atoms.
- Silicon, like carbon, has 4 valence electrons.
- In SiH4, silicon is bonded to four hydrogens, which also provides a total of 8 electrons (4 from silicon and 1 from each hydrogen).
- Thus, the octet for silicon is complete.

**Conclusion:** SiH4 is not electron-deficient.

### Step 3: Analyze SnCl4 (Tin(IV) Chloride)
- SnCl4 consists of one tin atom and four chlorine atoms.
- Tin has 4 valence electrons, and each chlorine atom has 7 valence electrons.
- In SnCl4, the tin atom shares its electrons with four chlorine atoms, satisfying the octet rule for both tin and chlorine.
- Each chlorine has 8 electrons (7 from itself and 1 from tin).

**Conclusion:** SnCl4 is not electron-deficient.

### Step 4: Analyze B2H6 (Diborane)
- Diborane consists of two boron atoms and six hydrogen atoms.
- Boron has 3 valence electrons. In B2H6, each boron atom shares its electrons with hydrogen atoms.
- However, each boron atom only has 6 electrons in total (3 from each boron and 1 from each hydrogen), which means they do not achieve a complete octet.
- The structure of diborane involves "banana bonds," where the boron atoms share electrons in a way that does not complete their octets.

**Conclusion:** B2H6 is electron-deficient.

### Final Answer:
Among the given options, **B2H6 (Diborane)** is the electron-deficient molecule.

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