How many possible chemical compounds are there?

Discussion in 'Chemistry' started by Magical Realist, Jul 5, 2013.

  1. Magical Realist Valued Senior Member

    "There are a huge number of possible chemicals. Estimates range from 1018 to 10200. For comparison the number of grains of sand on the Earth is about 7.5 x 1018, the number of particles in the universe is between 1072 and 1087. Clearly, if there really are more chemicals than this, then not every one even physically exists in the universe. The most abundant compound in the universe, by far, is diatomic hydrogen (H2) anyway.

    Out of the 117 known elements, only 94 are found naturally, and seven of these are noble gases, which only form compounds under very unusual conditions, such as when exposed to electron bombardment. This leaves 87 more elements to form chemical compounds, and most of these don't form many, nor are they very abundant.

    The most abundant elements in the universe are hydrogen (74%), helium (24%), oxygen (10%), carbon (0.46%), neon (0.13%), iron (0.1%), and nitrogen (0.1%). Helium and neon are noble gases and don't bond with anything. Iron mainly is locked up in iron oxide (rust). The others — carbon, hydrogen, oxygen, and nitrogen — are known by the acronym CHON, and together with phosphorous and sulfur, make up 99% of all living organisms, and more than 99% of all chemical compounds. These are called biological compounds.

    Biological compounds can form into long chains in ways that inorganic compounds can't. These compounds may be billions of atoms long, in the case of biopolymers such as DNA. These molecules may have tiny differences in just a few atoms, such as the genetic material of identical twins who have slight mutations due to copying errors or exposure to radiation. This produces an almost unlimited number of variations.

    In 2005, a group from the University of Berne, in Switzerland, tried to determine the total number of stable compounds with up to eleven atoms of just carbon, hydrogen, oxygen, nitrogen, and fluorine. Their number was just under 18 billion, but a subsequent analysis found they ignored many common chemicals, including many which could be easily ordered online, and the number may have been low by as much as three orders of magnitude. Even looking at just small chemicals, there is still an absolutely tremendous number of variations."---

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  3. exchemist Valued Senior Member

    ...which is why Chemistry remains a live subject in science, thank goodness.
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  5. Justin_Is_Here Registered Member

    You can just imagine total number of compounds present in universe. Everyday several new organic compounds are added to the list.
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  7. Captain Kremmen All aboard, me Hearties! Valued Senior Member

    Is it 1026?
  8. leopold Valued Senior Member

    probably 10 to the 26th power.
  9. KitemanSA Registered Senior Member

    To answer that question, determine the number on atoms in the universe, take its factorial, and square it... or there abouts.
  10. Arne Saknussemm trying to figure it all out Valued Senior Member

  11. exchemist Valued Senior Member

    Yeah, now, what was the question, again?
  12. nghia_dtvt5 Registered Member

    I thinks it's 42
  13. danshawen Valued Senior Member

    Compounds containing heavier or lighter isotopes of common substances, say, heavy water, are fundamentally different chemically. Drinking heavy water in place of ordinary water, for instance, is highly toxic. The number of possible variations of distinct chemical substances with different naturally occurring isotopes of common elements is correspondingly larger.
  14. DaveC426913 Valued Senior Member

    That set includes huge molecules such as proteins, enzymes RNA and DNA. Consider simply the number of possible permutations of a DNA molecule, as you'll start to get an inkling of the audacity of this question.
  15. Jake Arave Icthyologist/Ethologist Registered Senior Member

    For all intents and purposes, we'll say "almost infinite".
  16. river Valued Senior Member

    I thought at one time that the possible chemical compounds was limited

    not any more

    from what I have read

    I know agree the possibilities are , if not infinite , darn close to it
  17. Write4U Valued Senior Member

    I'm not sure if I understand the question, but if there are near infinite chemical compounds possible, then at some point the universe itself would be a compound.

    But as I understand it only a limited number of chemical elements (atoms) can be combined to form compounds. Their individual constituent atoms must be compatible and able to bond to begin with.

    Might it be better to say there is a near infinite number of chemical interactions, which would support the existence of naturally formed compounds in he universe, without making the universe itself a compound.
  18. exchemist Valued Senior Member

    I don't begin to follow why you say the universe itself would have to be a compound. That would imply that every atom was bound chemically to every other atom in the universe, which is self-evidently absurd. It's perhaps worth keeping mind that chemistry only exists in those parts of the universe cool enough for chemical bonds to reman intact. In stars for example, there is no chemistry because it is too hot for atoms to bond together at all.
  19. Write4U Valued Senior Member

    Of course I agree with you. But if all elements were able to bond, the universe would itself be a compound element. And that would be absurd. And of course this is why in the planck epoch of the universe, no chemicals or even atoms existed. As I understand it, quarks and leptons (essential in the formation of atoms) were some of the earliest particles to emerge from the chaos, long before the heavier elements appeared.

    But elements are "of their kind" and even as layman, it seems to me that some kinds cannot interact because they would annihilate one or each other, or revert back to simpler elements, due to loss of constituent particles.

    I have no clue how many elements can be formed, but it is obvious that the number is limited by natural restrictions.
  20. exchemist Valued Senior Member

    If all the elements were able to bond chemically, then you would still have huge amounts of matter in the universe that would not be chemically bound, due to the regimes, e.g. in stars, where matter is too hot for chemical bonds to form.

    What you seem to be talking about is something different, which is a "compound element." That implies nuclear binding, not chemical bonds. Chemistry forms compounds in which the atoms of the participating elements retain their integrity. To form new elements you need nuclear reactions.
  21. Write4U Valued Senior Member

    have enought data
    Yes, when I reread my post, I discovered my error. I was talking about compound elements (formed from joining different atoms), not basic elements (types of single atoms).

    I believe that my intuitive feeling is that in either case there can only be a limited number of possible atomic configurations.
    question: is there an equation of atomic structure?
    question: does chemical bonding depend on atomic structure?

    We know the properties of atomic nuclei and the rigid relationships between electrons, protons, and neutrons. This is probably more connected with physics, but if we fed everything we know about the fundamental atomic structural nature of known elements into a computer and compute the viability of all possible stable formations of elements. If we have enough data, it should be possible to calculate to a high degree and at the same time solve the question of chemical bonding of different elements.

    I think the estimates posted earlier are high. There may be environments that support unbalanced structures, But what we observe in the universe always falls within our known fundamental knowledge of elements. As I understand it, we have never found a newer element than those we can identify. We have made elements in a lab, but they do not exist in nature. Perhaps because they are unnecesary?
    Last edited: Dec 9, 2014
  22. exchemist Valued Senior Member

    I don't know about an "equation of atomic structure" exactly, but certainly there are patterns to nuclear stability, which varies as a function of the numbers of proton and neutrons present. This pattern follows rules predicted by quantum theory, in a somewhat analogous way to the rules of chemical stability of elements, which are predicted by applying quantum theory to the electrons (Schroedingers' equation and all that). But, being a chemist, I only learned about the electrons, not the nuclei.

    When a chemist talks of "atomic structure", he or she means the arrangement of electrons round the nucleus. The way this varies from one element to another is exactly what is responsible for explaining chemical bonding. In fact, the way the Periodic Table is laid out is according to this atomic structure, because that is what best correlates with chemical properties.

    Nuclear physicists talk of "nuclear structure", which explains nuclear stability and nuclear reactions. There are "islands of stability" corresponding to closed "shells" of nucleons, rather similar to the inert gases in chemistry which have closed shells of electrons. I understand that the quantum theory of the nucleus correctly predicts that increasingly heavy nuclei, say beyond uranium, tend to be less and less stable, which means increasingly liable to split or emit radioactive particles. That is the reason why a lot of these "transuranic" elements are only made in physics labs and only exist for a fleeting moment before they decay into something lighter.

    As for feeding data into a computer and predicting chemical bonding from it, this is in practice very hard indeed. In fact I don't think there is an exact solution for Schroedinger's equation for anything more complicated than the hydrogen molecule ion (H2+) ! See here for example
    Chemists rely on a large number of qualitative or semi-quantitative concepts to account for the chemistry for the elements, as there are many competing factors, once you have atoms with multiple electrons.
  23. Write4U Valued Senior Member

    Thank you for your responses. As layman I tend to oversimplify and I am sure these questions have been considered long before I asked them.

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