Which of the following compounds does not have similarity in their structural aspects?

Options

A. `FeSO_(4)*7H_(2)O`
B. `Na_(2)CO_(3)*7H_(2)O`
C. `MgSO_(4)*7H_(2)O`
D. `ZnSO_(4)*7H_(2)O`

Answer

To determine which of the following compounds does not have similarity in their structural aspects, we will analyze the given compounds based on their structural characteristics and isomorphism.

### Step 1: Identify the Compounds
The compounds provided are:
1. FeSO4·7H2O (Iron(II) sulfate heptahydrate)
2. Na2CO3·7H2O (Sodium carbonate heptahydrate)
3. MgSO4·7H2O (Magnesium sulfate heptahydrate)
4. ZnSO4·7H2O (Zinc sulfate heptahydrate)

### Step 2: Understand Isomorphism
Isomorphism refers to the similarity in the crystal structure of different compounds. For compounds to be isomorphous, they should have:
- Similar ionic sizes
- Similar coordination numbers
- Similar crystal lattice structures

### Step 3: Analyze the Compounds
- **FeSO4·7H2O, MgSO4·7H2O, and ZnSO4·7H2O**:
- These compounds contain the sulfate ion (SO4^2-) and metal cations (Fe^2+, Mg^2+, Zn^2+).
- The sulfate ion has a similar size and charge, and the metal cations are also divalent, which allows for similar structural characteristics.

- **Na2CO3·7H2O**:
- This compound contains the carbonate ion (CO3^2-) instead of the sulfate ion.
- The carbonate ion has a different geometry and bonding characteristics compared to the sulfate ion, leading to a different structural aspect.

### Step 4: Conclusion
Since Na2CO3·7H2O has a different anion (CO3^2-) compared to the other three compounds (which have SO4^2-), it does not share the same structural characteristics. Therefore, the compound that does not have similarity in its structural aspects is:

**Answer: Na2CO3·7H2O (Option B)**

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