Questions tagged [allotropes]

Different forms of an element which exist in the same state but have different molecular or crystalline structures. Classic examples of allotropes include diamond and graphite (allotropes of carbon), red phosphorous and white phosphorous, and $\ce{O2}$ and $\ce{O3}$ (allotropes of oxygen).

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46
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1answer
11k views

Why does sulfur, but not oxygen, catenate?

Oxygen is a rather boring element. It has only two allotropes, dioxygen and ozone. Dioxygen has a double bond, and ozone has a delocalised cloud, giving rise to two "1.5 bonds". On the other hand, ...
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6k views

Why do we not see silicon in a structure like graphite?

Silicon exists in a structure similar to diamond, with 4 silicon atoms bonded to each other in a tetrahedron. Why do we not see it exist in a structure like graphite? Is it even possible to get ...
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1answer
137 views

Which allotropes of sulfur exist naturally?

I'm writing a paper on chemistry and I would like to know which allotropes of sulfur exist naturally. I've searched on the Internet but I haven't found anything about natural sulfur allotropes except ...
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1answer
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Allotropy in Nitrogen and Bismuth of Group 15

Which elements of Group 15 of the periodic table have allotropes? P, As and Sb have well-known allotropes: P: White, Red and Black; As: Yellow, Black and Gray (Grey); Sb: White, Yellow and Black....
7
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1answer
9k views

Why does ozone have higher entropy than oxygen?

$$\ce{3O2(g) -> 2O3(g)} \qquad \Delta H^\circ (\pu{298 K}) = \pu{+142 kJ mol^-1}$$ Since the RHS of the equation contains less number of gaseous molecules, naturally I expected the $\Delta S$ to ...
12
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1answer
455 views

Allotropes of Phosphorus

Something I noticed whilst revising about group 15 is that the darker the allotrope of phosphorus, the more stable it is. white/yellow – very volatile, soluble, pyrophoric red – air ...
7
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1answer
9k views

Which allotrope of phosphorus is kinetically the most stable?

Which allotrope of phosphorus is kinetically the most stable? I ruled out white and yellow as being quite reactive. Red and black allotropes are both polymeric and comparitively less reactive. ...
5
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1answer
129 views

Polycyclic nitrogen network?

So today I suddenly stricken with this structure and started to wonder if this polymeric structure of nitrogen is possible or not? If possible then what's its stability?
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2answers
90 views

Stability of α, β, γ allotropes at different temperatures

While reading about elements or compounds I often come across allotropes (or forms) being referred to as α, β, γ forms. Examples: Sulfur has two allotropes: α rhombic and β monoclinic. Out of these ...
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1answer
470 views

Does sulfur have various allotropes at room temperature?

Recently I had a question in my chemistry test that said: Which of the following nonmetals does not have multiple allotropes at room temperature? A) Oxygen B) Hydrogen C) Sulfur D) ...
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1answer
550 views

Are allotropes of sulfur two different phases?

Monoclinic sulfur and rhombic sulfur are two allotropes of sulfur. In phase equilibria, part of the system that is having distinct boundary, mechanically separable and different chemical or physical ...