- #1
LogicalAcid
- 137
- 0
Why do some atoms bind with other atoms of their own elements, such as O2 and N2, and why do others not? What property of these atoms enable them to do this?
How are diatomic molecules formed?
- Thread starter LogicalAcid
- Start date
-
- Tags
- Molecules
In summary, some atoms bind with other atoms of their own elements due to a property called a "full octet", which makes them more stable. However, there are some exceptions, such as Beryllium, which form a "covalent-ish" bond that is stronger than a typical dispersion force. This is due to the strong correlation of electrons. All elements, except for noble gases, can form diatomic molecules in gas phase, but some are more stable than others due to their energy levels. Carbon is an example of an element that forms diatomic molecules.
- #2
espen180
- 834
- 2
Are you asking about covalent bonds exclusively? The short answer is that "a full octet is more stable, so they share their electrons", but this does not cover the atoms that no not form covalent dimers, like Be. The long answer involves what are called binding and antibinding molecular orbitals. I advice you to consult any first year university chemistry textbook for an introduction to this topic.
- #3
alxm
Science Advisor
- 1,848
- 9
espen180 said:
Ah, but Beryllium http://www.sciencemag.org/content/324/5934/1548.abstract" form a covalent dimer! Or perhaps I should say 'covalent-ish'; there really isn't a word for that peculiar bond, although it's certainly stronger than can be accounted for by 'proper' dispersion forces (which is what most theory would predict to be the only bonding force). You could say the bond is too weak to be covalent and too short to be dispersion.
It's a noteworthy failure of all the simple bonding theories (MO, VB, Lewis).
Last edited by a moderator:
- #4
espen180
- 834
- 2
Wow, thanks for that interesting read! 
Judging by the references provided, all the Earth alkali metals actually form dimers! My first "instinct" is that the error of the standard bonding models arise because they don't take into account the effect of both nuclei on the electron wavefunctions. Is that the case?
Judging by the references provided, all the Earth alkali metals actually form dimers! My first "instinct" is that the error of the standard bonding models arise because they don't take into account the effect of both nuclei on the electron wavefunctions. Is that the case?
- #5
DrDu
Science Advisor
- 6,345
- 970
No, the nuclei aren't important. The binding in Be_2 etc. is so complicated due to strong correlation of the electrons.
- #6
LogicalAcid
- 137
- 0
DrDu said:
I still don't see how they form. I mean I know Alkaline metals are reactive, but Nitrogen and Oxygen due this. Why don't other elements? And both ionic and covalent bonds.
- #7
DrDu
Science Advisor
- 6,345
- 970
I don't see the basis for your question. In gas phase, homonuclear diatomic molecules of practically all elements have been observed. With the exception of the bonding between noble gasses, these bonds are considerably stronger than van der Waals bonds, i.e. they are really covalent bonds. The classic reference is G. Herzberg, Molecular Spectra and Molecular Structure: Spectra of Diatomic Molecules
- #8
Borek
Mentor
- 28,947
- 4,238
If I understand correctly what is LogicalAcid current level of education, diatomics other than those most basic (H2, N2, O2 and halogens) are too esoteric to be not confusing.
It is all in energy - those commonly observed have much lover energy than atomic gases, so they dominate in conditions that we assume standard (around 1 atm and around room temperature). Those exotic ones have lower energy too, but the difference is very small, so they can survive only in gas phase and at low pressures, as in the presence of other elements they have many other ways of getting to the lowest energy state.
It is all in energy - those commonly observed have much lover energy than atomic gases, so they dominate in conditions that we assume standard (around 1 atm and around room temperature). Those exotic ones have lower energy too, but the difference is very small, so they can survive only in gas phase and at low pressures, as in the presence of other elements they have many other ways of getting to the lowest energy state.
Last edited:
- #9
DrDu
Science Advisor
- 6,345
- 970
You are probably right Borek, nevertheless then I do not quite understand what the question is. Maybe that not for all elements the diatomic molecules are the most stable ones in comparison with other struktures? I think LocigalAcid could precise that point.
- #10
LogicalAcid
- 137
- 0
DrDu said:
Basically, why do some elements form diatomic molecules and others not?
- #11
DrDu
Science Advisor
- 6,345
- 970
Tell me an element besides the noble gasses which does not form a diatomic molecule.
- #12
LogicalAcid
- 137
- 0
DrDu said:
I believe Carbon does not.
- #13
DrDu
Science Advisor
- 6,345
- 970
It does.
1. How do diatomic molecules form?
Diatomic molecules form through a process called bonding, where two atoms share electrons to create a stable molecule. This can happen through either covalent bonding, where the atoms share electrons equally, or ionic bonding, where one atom gives up an electron to the other.
2. What types of diatomic molecules exist in nature?
The most common type of diatomic molecules found in nature are homonuclear diatomic molecules, which consist of two atoms of the same element bonded together. Examples include oxygen (O2), nitrogen (N2), and hydrogen (H2).
3. How are diatomic molecules different from polyatomic molecules?
Diatomic molecules are composed of only two atoms, while polyatomic molecules contain more than two atoms. Diatomic molecules also tend to be more stable and have simpler structures compared to polyatomic molecules.
4. Can diatomic molecules exist in a gaseous state?
Yes, many diatomic molecules exist in a gaseous state at room temperature, such as hydrogen (H2), oxygen (O2), and nitrogen (N2). They can also exist in other states of matter, such as liquids (e.g. water) and solids (e.g. iodine).
5. How are diatomic molecules important in chemical reactions?
Diatomic molecules play a crucial role in many chemical reactions because they are often the building blocks of more complex molecules. They can also participate in reactions themselves, either by breaking apart or combining with other atoms to form new molecules.
Similar threads
-
Chemistry
-
Chemistry
-
Chemistry
-
Atomic and Condensed Matter
-
Atomic and Condensed Matter
-
Chemistry