# Allotropy in Nitrogen and Bismuth of Group 15

Which elements of Group 15 of the periodic table have allotropes?

P: White, Red and Black;
As: Yellow, Black and Gray (Grey);
Sb: White, Yellow and Black.

What about Nitrogen and Bismuth?

• The same source suggests that Nitrogen has an allotrope named Dinitrogen while Bismuth has none.

• Chemwiki says:

$\ce{N2}$ does not have any allotropes.

and doesn't comment on Bismuth.

• Royal Society of Chemistry says yes for Nitrogen and no for Bismuth.

• Inorganic Reactions and Methods: The Formation of Bonds to N, P, As, Sb, Bi (Part 1), Volume 7 has an article which suggests that Bismuth allotrope exists.

• This not so reliable source says no for Bismuth.

• Wikipedia doesn't mention anything for Bismuth but for Nitrogen:

At atmospheric pressure, molecular nitrogen condenses (liquefies) at $\pu{77 K}$ ($\pu{−195.79^\circ C}$) and freezes at $\pu{63 K}$ ($\pu{−210.01^\circ C}$) into the beta hexagonal close-packed crystal allotropic form.

Unstable allotropes of nitrogen consisting of more than two nitrogen atoms have been produced in the laboratory, like $\ce{N3}$ and $\ce{N4}$. Other (as yet unsynthesized) allotropes include hexazine and octaazacubane.

According to me, nitrogen has allotropes and bismuth doesn't, but the above sources contradict. Any clarifications and reasons for them showing or not showing allotropy would be appreciated.

• I feel that the question has become so dense that it might already have the answer. – Del Pate Apr 1 '15 at 19:05
• Solid nitrogen exists in 2 states Alpha nitrogen having cubical structure. Beta nitrogen having hexagonal crystalline structure. – Sravan Chittupalli Sep 8 '16 at 9:14