Question

The Formula Si 4 Nz Clq Hz can maky many different compounds. Identify the a most stalole monocyclic compounds. Iustify why you think the isomers chosen are the most stable variations compared t to the other possibilities? Justify using e the rules that helped you got this answer. €

formula is Si₄N₂Cl₈H₂

Answer 1

The question gives us a vague formula - Si4N2Cl8H2

The key to solving this problem is to think of the silicon atoms as carbon atoms . In fact, silicon can form chains that are 7 or 8 atoms long.

This formula attunes to a monocyclic compound. The straight chain will require more hydrogens .

Now, think of a 6 member cyclic compound, with 4 silicons and 2 nitrogens. We have to now figure out the order in which they'll be present and where the hydrogens and chlorines will go.

Firstly, think of atomic size and bond strength. The nitrogen and hydrogen atoms are small in size, compared to chlorine and silicon.

Nitrogen cannot possibly hold a chlorine atom in a stable covalent manner. So , all chlorines must be bonded to the silicon atoms.

The 2 hydrogens are hence bonded to one nitrogen each.

Next comes stability. Which way should they be present?

Think of some ways that would make the structure stable. Like resonance and hyperconjugation.

Since this compound is not aromatic, we have to place the nitrogens in a way such that either resonance or hyperconjugation stabilises the intermediates formed. This is possible only due to the lone pairs on nitrogen and silicon only acts like a carbon.

These must be 2 possible ways to achieve this.

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