Boron with hydrogen forms a number of hydrides which are known
are boranes. These hydrides are classified into closoboranes and nidoboranes. The simplest hydride of boron is diborane. Boron
apart from having `(2c, 2e)` bonds also contain `(3c, 2e)` bonds.
Three centre two electron `(3c, 2e)` bond is present in :

Options

A. `BCl_(3)`
B. `B(OH)_(3)`
C. `B_(2)H_(6)`
D. `B_(4)H_(10)`

Answer

To determine which of the given compounds contains a three-center two-electron (3c, 2e) bond, we will analyze the structures of the compounds mentioned in the question: BCl3, BOH3, B2H6, and B4H10.

### Step-by-Step Solution:

1. **Understanding 3c, 2e Bonds**:
- A three-center two-electron bond involves three atoms sharing two electrons. This is commonly found in certain boron hydrides.

2. **Analyzing BCl3**:
- BCl3 (Boron Trichloride) has a trigonal planar structure. Each boron-chlorine bond is a two-center two-electron bond. There are no three-center two-electron bonds present in BCl3.
- **Conclusion**: BCl3 does not have a 3c, 2e bond.

3. **Analyzing BOH3**:
- BOH3 (Orthoboric Acid) also has a trigonal planar structure. The bonds formed between boron and hydroxyl groups are two-center two-electron bonds. There are no three-center two-electron bonds in this compound.
- **Conclusion**: BOH3 does not have a 3c, 2e bond.

4. **Analyzing B2H6**:
- B2H6 (Diborane) has a unique structure where it contains both two-center two-electron bonds and three-center two-electron bonds. The B-H-B bonds in diborane are examples of 3c, 2e bonds.
- **Conclusion**: B2H6 contains a 3c, 2e bond.

5. **Analyzing B4H10**:
- B4H10 (Tetraborane) is formed from two molecules of B2H6. It also contains 3c, 2e bonds similar to those found in diborane.
- **Conclusion**: B4H10 contains a 3c, 2e bond.

### Final Answer:
The compounds that contain a three-center two-electron bond are **B2H6 (Diborane)** and **B4H10 (Tetraborane)**.