2006-07-09 12:34:19 · 2 answers · asked by Anonymous in Science & Mathematics ➔ Chemistry
Aromatic compounds are stabilized because of conjugation/resonance.
Pentalene is a polycyclic hydrocarbon composed of two fused cyclopentadiene rings. However it is not aromatic. Although it meets most criteria for aromatics (cyclic, planar molecule, complete conjugation) it fails at one: an aromatic compound must contain an odd number of pairs of pi electrons; ie it must satisfy Huckel's rule: (4n+2) pi electrons, where n is an integer starting at zero.
Pentalene has 8 pi electrons.
On the other hand, the dianion has 10 (4*2+2) pi electrons. Thus all criteria are met, the dianion is a true aromatic compound and its stability stems from its aromatic character.
2006-07-11 02:35:03 · answer #1 · answered by bellerophon 6 · 3⤊ 1⤋
Because the dianion acts as a catalyst for "penta line"
therefor , it is a compound that is stable
2006-07-09 19:52:57 · answer #2 · answered by antman611756 2 · 0⤊ 0⤋