Give the number of pair enantiomer of `[Ma_(2)b_(2)cd]` .

Explanation

To determine the number of pairs of enantiomers for the coordination compound \([Ma_2b_2cd]\), we will follow these steps:

### Step 1: Identify the Coordination Number and Geometry
The coordination compound \([Ma_2b_2cd]\) has a coordination number of 6, which typically indicates an octahedral geometry.

**Hint:** Remember that the coordination number indicates how many ligands are attached to the central metal atom.

### Step 2: Determine the Isomer Types
In octahedral complexes, we can have different types of isomers, including cis and trans isomers. For the given complex, we need to focus on the cis isomer because only the cis isomer will be optically active (i.e., capable of having enantiomers).

**Hint:** Consider how the arrangement of ligands affects the symmetry of the complex.

### Step 3: Draw the Cis Isomer
For the cis isomer of \([Ma_2b_2cd]\), we can arrange the ligands as follows:
- Place two A ligands adjacent to each other.
- Place the B ligand adjacent to one of the A ligands.
- Place C and D in the remaining positions.

This arrangement will look like this:
```
A
/ \
B A
/ \
C D
```

**Hint:** Visualize the arrangement of ligands in 3D to understand how they occupy space around the metal center.

### Step 4: Identify the Mirror Image
Next, we need to draw the mirror image of the cis isomer. The mirror image will switch the positions of the ligands, creating a non-superimposable structure.

**Hint:** Remember that in a mirror image, left and right positions are swapped.

### Step 5: Count the Pairs of Enantiomers
Since we have one cis isomer and its mirror image, we have one pair of enantiomers. Therefore, the number of pairs of enantiomers for the complex \([Ma_2b_2cd]\) is 1.

**Hint:** Enantiomers always come in pairs, so count them accordingly.

### Final Answer
The number of pairs of enantiomers of \([Ma_2b_2cd]\) is **1**.