Tuesday, April 5, 2011

Word Verifications: Isotope and Allotrope

wv = "isotope": noun. The prefix iso is obvious and means the same in Greek.  Topos as in topography has the meaning of place. The word isotope was coined by a Greek-schooled physician named Margaret Todd to convey the notion of at the same place in the Periodic Table. Thus only chemical species with different numbers of protons get separate seats at the Table. Elements having different numbers of neutrons must share the same seat. This is also true for radioisotopes.

wv =  "allotrope": noun:  The prefix allo is related to the Greek allos meaning other. Trope is a confusing root and in my opinion is a vague word having several different meanings. The combination allotrope means a structurally different form of the same element ("Graphite and diamond are allotropes of carbon"). 

Phosphorus and especially sulfur are allotrope-rich. The concept of allotrope is akin to an elemental alias. Sulfur has several different aliases or allotropes. Yes, I like that.

7 comments:

  1. Sulfur has another alias: brimstone. The notions of brimstone and hell and (by association) Satan and different disguises must be ancient. Sulfur held a special place amongst the eary chemists (al-chemists).

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  2. I think it's time for you to apply your chemical (or alchemical) genius into turning wanter to wine and feldspar into gold.

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  3. Wassonite is a mineral formed from only two elements, sulfur and titanium. How does this form in nature, create a (unique) crystal structure and remain stable?

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  4. Wassonite is a mineral formed from only two elements, sulfur and titanium.

    Minerals formed of only two elements are called binary combination. Other examples are cinnabar (HgS), galena (PbS, lol PBS-get it?) and molybdenite (MoS2).

    My astonishment is not that wassonite exists but rather why doesn't it exist more often? I suspect that the reason is that most of the world's titanium is tied up as the oxide. Some metals have stronger affinities for oxygen versus sulfur- it's a hard/soft thang. Titanium dioxide (the stuff of white paint) is thermodynamically more stable than wassonite, the corresponding disulfide. So, in a primordial soup, the titanium would more strongly bind to oxide than to sulfide. This preference is reversed for mercury, lead, and molybdenum-the sulfides are more stable.

    The upshot is that Wassonite exists because it formed in an anaerobic atmosphere or a non oxide place i.e., not of this earth. I'd be surprised if it had never been synthesized before though.

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  5. Wouldn't it break down/degrade naturally in an oxygen rich environment?

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  6. Wouldn't it break down/degrade naturally in an oxygen rich environment?

    Many things are unstable with respect to oxygen and yet inert. It is a special property of dioxgen which I tried (poorly) to explain back here.

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  7. Now if Wassonite were to bathe in water, it might degrade into the oxide as sulfide is swapped for oxide.

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