Thoughts about stability of chemical compounds

anonymous63 — Wed, 12 Aug 2009 16:28:51 +0000

Today, while reminiscing about my last weekend biking trip that lead through an old mining village I remembered reading an article describing some rare minerals found in those mines. Then I remembered my recent visit to the museum of natural history where I saw in the geology section various minerals naturally occurring on our planet. Many of them are chemically very similar and I wondered whether the set of chemical compounds that can be found on the planet (minerals) is limited. Alternatively it is conceivable that any combination of chemical compounds can be (has been) created by geological processes. In that case it would be futile to try to name all of the combinations of chemical elements as their number is huge. But is it infinite? Minerals are composed of chemical elements. When we look at the periodic table of elements, we can see that there is not an infinite number of them; in fact, as we go towards the heavy elements we start encountering radioactive ones that have a finite lifespan (or close to it). So we can see there are natural laws that restrict the number of stable elements. This fact is putting one kind of limit on the number of minerals*. Another one is that not all spatial arrangements of elements are possible. So the conclusion is – the number of minerals that can naturally occur is finite**.
Recently I read an article about search for new chemical elements and learned about a hypothesis that predicted islands of stable isotopes. The conjecture in the hypothesis postulated that stability of isotopes is dictated by spatial arrangement of protons and neutrons in the cores. As a consequence, we can say that there is only one cause limiting the number of naturally occurring minerals – a structural arrangement of the constituents on 2 levels – neutrons and protons on the lower and chemical elements on the upper one.

* We can define minerals as chemical compounds stable enough to live long enough to be found on the planet. Apparently this set does not have sharp boundary as it’s definition relies on a fuzzy term “stable”. But for the sake of this study the intuitive feel we have when we think about the set is sufficient.

** Currently there are about 3,000 to 4,000 known minerals

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Thoughts about stability of chemical compounds