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).
30
questions
2
votes
0answers
58 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 ...
0
votes
0answers
76 views
What is “activated red phosphorus”? What made it so long to be discovered?
[WP = white phosphorus ; RP = red phosphorus ; ARP = activated red phosphorus]
Tom from Extraction & Ire did a video two years ago(2018) on converting WP to RP by keeping the former in sunlight ...
2
votes
1answer
73 views
Predicting sign of enthalpy of allotropic transition of phosphorus
How to predict the sign of enthalpy during the transition
$$\ce{P(s, white) -> P(s, red)}?$$
$\ce{P(s, red)}$ is more stable than $\ce{P(s, white)}$ due to release in angle strain.
Since during ...
0
votes
0answers
29 views
Can other group IV elements form graphene analogs with interesting properties? [duplicate]
Graphene has gathered quite a bit of press due to its unique physical properties which hold enormous promise in a wide range of applications from semiconductors to high strength materials. Given that ...
0
votes
1answer
61 views
Se+P White or red P?
I read this in an old chemistry book. It says:
When selenium is dropped into melted phosphorus, it dissolves rapidly, and the compound sinks through the liquid phosphorus in red streaks.
My ...
5
votes
0answers
64 views
What is tetrasulfur like? Why is there so little experimental information about it?
Phys.org's How sulfur helped make Earth habitable before the rise of oxygen says
Mapping the bonds and vibrational modes of molecules containing sulfur isotopes is helping to shed light on the ...
0
votes
0answers
25 views
why is white phosphorous given to have ZERO standard heat of formation [duplicate]
why is white phosphorous given to have ZERO standard heat of formation??
while it is well known fact that white phosphorous is highly reactive and is obviously less stable than red and black ...
18
votes
4answers
1k views
Does a neutral dimercury molecule exist?
Is a neutral $\ce{Hg2}$ molecule possible, as a gas under extremely low (partial) pressures? What is the enthalpy of formation or similar?
It is my impression that usual mercury vapors are monatomic? ...
0
votes
1answer
214 views
Why does diamond have no molecular formula?
Why does diamond have no molecular formula, while buckminsterfullerene does have it, despite both being allotropes of the same element?
2
votes
4answers
6k views
Calling Diamond an element?
Is it scientifically correct to call Diamond an element? Carbon has a wide range of allotropes, so would it be correct to actually just call graphite, diamond etc an element. For that matter, could we ...
7
votes
1answer
7k 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 ...
5
votes
1answer
116 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?
2
votes
0answers
1k views
Allotropes of hydrogen
Is it possible to chemically bond 8 hydrogen atoms together to form an allotrope like $\ce{H8}$?
1
vote
1answer
439 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) ...
15
votes
4answers
4k views
Aside from carbon, what other substances can be made “superhard”?
So diamonds are an allotrope of carbon, that is formed when carbon is put under immense pressure, right? What other elements or compounds can you make into "diamonds", as in more durable, harder ...
0
votes
1answer
486 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 ...
2
votes
1answer
3k views
Solubility of white phosphorus
Why is white phosphorus soluble in $\ce{CS2}$ but red phosphorus not? Is it something in relation with the structures of both? Please explain.
1
vote
1answer
137 views
Is Nuclear Spin Isomer a kind of allotrope?
In my book there's a question:
Does $\ce{H2}$ shows allotropy ? Enlist its allotropes and their application?
I pondered over different way Hydrogen can be arranged(I don't know but I have weak ...
1
vote
1answer
1k views
Is Changing between Allotropic forms a Physical or Chemical Process?
When a substance changes its alloptropic form, is this considered a physical change or a chemical change?
Right now, I am thinking that it would depend on what the change was. For example, if ...
-1
votes
2answers
348 views
Is ozone really a chemical element?
In our chemistry book is written that ozone ($\ce{O3}$) is a chemical element. Also our chemistry book gives a definition that agrees with that. But our teacher doesn't agree.
His reasons:
If ...
1
vote
1answer
1k views
Which elements exhibit allotropy?
I was just reading this article about allotropes which relates allotropy with some specific elements and also this wiki article. Also some other articles some of which relate allotropy with catenation ...
11
votes
1answer
422 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 ...
9
votes
1answer
5k 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 ...
7
votes
1answer
8k 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.
...
4
votes
1answer
11k views
Allotropy and polymorphism
Polymorphism is defined as the ability of a solid material to exist in more than one form or crystal structure, whereas allotropy is defined as the property of some chemical elements to exist in two ...
3
votes
1answer
20k views
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....
6
votes
2answers
961 views
Can powdered beta-tin be made from raising the temperature of alpha-tin?
When white tin ($\beta$-tin) is cooled to a temperature below $13.2\ \mathrm{^\circ C}$, it creates the allotrope of gray ($\alpha$-tin), a gray, amorphous powder.
My question is that once you have ...
2
votes
1answer
260 views
Does single-layered Aluminium Phosphide exist?
I'm currently working with the band structure of graphene and graphene-like compounds.
Ī±-Boron Nitride (hexagonal, single layer) has many interesting properties. I was wondering if the next period ...
9
votes
3answers
22k views
Is diamond an allotrope or polymorph of carbon?
Is diamond an allotrope or polymorph of carbon? When is something considered an allotrope vs a polymorph?
43
votes
1answer
10k 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, ...
