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Alternative interpretations

Is science sometimes in danger of getting tunnel vision? Recently published ebook author, Ian Miller, looks at other possible theories arising from data that we think we understand. Can looking problems in a different light give scientists a different perspective?

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Do we understand the chemical bond?
Following the Alternative interpretations theme, I shall write a series of posts about the chemical bond. As to why, and I hope to suggest that there is somewhat more to the chemical bond than we now consider. I suspect the chemical bond is something almost all chemists "know" what it is, but most would have trouble articulating it. We can calculate its properties, or at least we believe we can, but do we understand what it is? I think part of the problem here is that not very many people actually think about what quantum mechanics implies.

In the August Chemistry World it was stated that to understand molecules, all you have to do is to solve the Schrödinger equation for all the particles that are present. However, supposing this were possible, would you actually understand what is going on? How many chemists can claim to understand quantum mechanics, at least to some degree? We know there is something called "wave particle duality" but what does that mean? There are a number of interpretations of quantum mechanics, but to my mind the first question is, is there actually a wave? There are only two answers to such a discrete question: yes or no. De Broglie and Bohm said yes, and developed what they call the pilot wave theory. I agree with them, but I have made a couple of alterations, so I call my modification the guidance wave. The standard theory would answer no. There is no wave, and everything is calculated on the basis of a mathematical formalism.

Each of these answers raises its own problems. The problem with there being a wave piloting or guiding the particle is that there is no physical evidence for the wave. There is absolutely no evidence so far that can be attributed solely to the wave because all we ever detect is the particle. The "empty wave" cannot be detected, and there have been efforts to find it. Of course just because you cannot find something does not mean it is not there; it merely means it is not detectable with whatever tool you are using, or it is not where you are looking. For my guidance wave, the problem is somewhat worse in some ways, although better in others. My guidance wave transmits energy, which is what waves do. This arises because the phase velocity of a wave equals E/p, where E is the energy and p the momentum. The problem is, while the momentum is unambiguous (the momentum of the particle) what is the energy? Bohm had a quantum potential, but the problem with this is it is not assignable because his relationship for it did not lead to a definable value. I have argued that to make the two slit experiment work, the phase velocity should equal the particle velocity, so that both arrive at the slits at the same time, and that is one of the two differences between my guidance wave and the pilot wave. The problem with that is, it puts the energy of the system at twice the particle kinetic energy. The question then is, why cannot we detect the energy in the wave? My answer probably requires another dimension. The wave function is known to be complex; if you try to make it real, e.g. represent it as a sine wave, quantum mechanics does not work.

However, the "non-real" wave has its problems. If there is actually nothing there, how does the wave make the two-slit experiment work? The answer that the "particle" goes through both slits is demonstrably wrong, although there has been a lot of arm-waving to preserve this option. For example, if you shine light on electrons in the two slit experiment, it is clear the electron only goes through one slit. What we then see is claims that this procedure "collapsed the wave function", and herein lies a problem with such physics: if it is mysterious enough, there is always an escape clause. However, weak measurements have shown that photons go though only one slit, and the diffraction pattern still arises, exactly according to Bohm's calculations (Kocsis, S. and 6 others. 2011. Observing the Average Trajectories of Single Photons in a Two-Slit Interferometer Science 332: 1170 – 1173.) There is another issue. If the wave has zero energy, the energy of the particle is known, and following Heisenberg, the phase velocity of the wave is half that of the particle. That implies everything happens, then the wave catches up and sorts things out. That seems to me to be bizarre in the extreme.

So, you may ask, what has all this to do with the chemical bond? Well, my guidance wave approach actually leads to a dramatic simplification because if the waves transmit energy that equals the particle energy, then the stationary state can now be reduced to a wave problem. As an example of what I mean, think of the sound coming from a church organ pipe. In principle you could calculate it from the turbulent motion of all the air particles, and you could derive equations to statistically account for all the motion. Alternatively, you could argue that there will be sound, and it must form a standing wave in the pipe, so the sound frequency is defined by the dimensions of the pipe. That is somewhat easier, and also, in my opinion, it conveys more information.

All of which is all very well, but where does it take us? I hope to offer some food for thought in the posts that will follow.
Posted by Ian Miller on Aug 28, 2017 12:19 AM BST
Where to Publish?
In a recent Chemistry World there was an item on chemistry in India, and one of the things that struck me was that Indian chemists seemed to be criticized because they published a very low proportion of the papers in journals such as JACS and Angewandte Chemie. The implication was, only the "best" stuff gets published there, hence the Indian chemists were not good enough. The question I want to raise is, do you think that reasoning is valid?
One answer might be that these journals (but not exclusively) publish the leading material, i.e. they lead the way that chemistry is taking in the future. When I started my career, these high profile journals were a "must read" because they were where papers that at least editors felt was likely to be of general interest or of practical interest to the widest number of chemists were published.
But these days, these sort of papers do not turn up. There may be new reactions, but they are starting to involve difficult to obtain reagents, and chemical theory has descended into the production of computational output. These prestige journals have moved on to new academic fields, which is becoming increasingly specialized, which increasingly needs expensive equipment, and which also needs a school that has been going for some time, so that the background experience is well embedded. There are exceptions, but they do not last, thus graphene was quite novel, but not for long. There are still publications involving graphene, but chemists working there have to have experience in the area to make headway. More importantly, unless the chemist is actually working in the area, (s)he will never touch something like graphene. I am certainly not criticizing this approach by the journals. Rather I am suggesting the nature of chemical research is changing, but I feel that in countries where the funding is not there to the same extent, chemists may well feel they might be more productive not trying to keep up with the Joneses.
Another issue is, by implication it is claimed that work published in the elite journals is more important. Who says? Obviously, the group who publish there, and the editorial board will, but is this so? There may well be work that is more immediately important, but to a modest sized subset of chemists working in a specific area. Now the chemist should publish in the journal that that subset will read.
My view is that chemistry has expanded into so many sub-fields that no chemist can keep up with everything. When I started research, organic chemists tended not to be especially interested in inorganic or physical chemistry, not because they were not important, but simply because they did not have the time. Now it has got much worse. I doubt there is much we can do about that, but I think it is wrong to argue that some chemistry that can only be done in very richly funded Universities is "better" or more important than a lot of other work that gets published in specialized journals. What do you think?
Posted by Ian Miller on Jul 3, 2017 3:23 AM BST
Where did life begin?
Some time ago now I published an ebook "Planetary Formation and Biogenesis", which started with a review including over 600 references, following which I tried analyzing their conclusions and tried to put them together to make a coherent whole. This ended up with a series of conclusions and predictions on what we might find elsewhere. It was in light of this I saw the article in the May edition of "Chemistry World". That article put up reasons to back some of the various thoughts as to where life started, but I found it interesting that people formed their views based on their chemical experience, and they tended to carry out experiments to support that hypothesis. That, of course, is fair enough, but it still misses what I believe to bee the key point, and that is, what is the most critical problem to overcome to get life started, and how hard is it to do?

The hardest thing, in my opinion, is not to make polymers. I know that driving condensation reactions forwards in water is difficult, but as Deamer pointed out in the article, if you can get a lipid equivalent, it is by no means impossible. No, in my opinion, the hardest thing to do is to make phosphate esters. Exactly how do you make a phosphate ester? As Stanley Miller once remarked, you don't start with phosphoryl chloride in the ocean. The simplest way is to heat a phosphate and an alcohol to about 200 degrees C.  Of course, water will hydrolyse phosphate esters at 200 degrees C, so unless you drive off the water, which is difficult to do in an ocean, high temperature is not your friend because the concentration of water in the ocean always exceeds the concentration of phosphate or alcohol. You simply cannot do that around black smokers.

The next problem is, why did nature choose ribose? Ribose is not the only sugar that permits the formation of a duplex when suitably phosphated and bound to a nucleotide. Almost all other pentoses do it. So the question remains, why ribose? The phosphate ester is an important solubilizing agent for a number of biochemicals necessary for life but it invariably occurs bound to a ribose, which in turn is usually bound to adenine. The question then is, is this a clue? If so, why is it largely unnoticed? My conclusion was, ribose alone can form a phosphate ester on a primary alcohol group in solution because only ribose naturally has reasonable concentrations of itself in the furanose form.

It was not always unnoticed. There is a clearly plausible route, substantiated by experiment (Ponnamperuma, C., Sagan, C., Mariner, R., 1963. Synthesis of adenosine triphosphate under possible primitive earth conditions. Nature 199: 222-226.) that shows the way. What was shown here was that if you have a mixture of adenine, ribose and phosphate, and shine UV light that can be absorbed by the adenine, you make adenosine, and then phosphate esters, mainly at the 5 position of the furanose form, so you can end up with ATP, a chemical still used by life today. Why is that work neglected? Could it be that nobody these days goes back and reads the literature from 1963?
Why does this synthesis work? My explanation is this. You do not have to get to 200 degrees to form a phosphate ester. What you have to do is provide an impact between the alcohol group and phosphate equivalent to that expected at 200 degrees. If we think about the experiment described above, there is no way an excited electronic state of adenine can be delocalized into the ribose, so why is the light necessary?

My conclusion was that the excited state of the adenine can decay so that quite a considerable amount of vibrational energy is generated. That will help form the adenosine, but after that the vibrational energy will spread through the sugar. Now we see the advantage of the furanose: it is relatively floppy, and it will vibrate well, and even better, the vibrational waves will focus at C-5. That is how the phosphate ester is formed, and why ribose is critical. The pyranose forms are simply too rigid to focus the mechanical vibrations. Once you get adenosine phosphate, in the above experiment the process continued to make polyphosphates, but if  some adenosine was also close by, it would start to form the polymer chain. Now, if that is true, then life must have started on the surface, either of the sea or on land. My view is the sea is more probable, because on land it is difficult to see where further biochemicals can come from.
Posted by Ian Miller on May 28, 2017 11:45 PM BST
What Role Theory?
One issue that has puzzled me is what role, if any, does theory play in modern chemistry, other than having a number of people writing papers. Of course some people are carrying out computations, but does any of their work influence other chemists in any way? Are they busy talking to themselves? The reason why this has struck me is that the latest "Chemistry World" has an article "Do hydrogen bonds have covalent character?" Immediately below is the explanation, "Scientists wrangle over disagreement between charge transfer measurements." My immediate reaction was, what exactly is meant by "covalent character" and "charge transfer"?  I know what I think a covalent bond is, which is a bond formed by two electrons from two atoms pairing to form a wave function component with half the periodic time of the waves on the original free atom. I also accept the dative covalent bond, such as that in the BH3NH3 molecule, where two electrons come from the same atom, and where the resultant bond has a strength and length as if the two electrons originated from separate atoms. That is clearly not what is meant for the hydrogen bond, but the saviour is that word "character".  What does that imply?
 What puzzles me here is that on reading the article, there are no charge transfer measurements. What we have, instead, are various calculations based on models, and the argument is whether the model involves transfer of electrons. However, as far as I can make out, there is no observational evidence at all. In the BH3NH3 molecule, obviously the two electrons for the bond start from the nitrogen atom, but the resultant dipole moment does not indicate a whole electron is transferred, although we could say it is, and then sent back to form the bond. However, in that molecule we have a dipole moment of over 6 Debye units. What is the change of dipole moment in forming the hydrogen bond? If we want to argue for charge transfer, we should at least know that.
From my point of view, the hydrogen bond is essentially very weak, and is at least an order of magnitude less strong than similar covalent bonds. This would suggest that if there were charge transfer, it is relatively minor. Why would such a small effect not be simply due to polarization? With the molecule BH3NH3 it is generally accepted that the lone pair on the ammonia enters the orbital structure of the boron system, with both being tetrahedral in structure, more or less. The dipole moment is about 6 Debye units, which does not correspond to one electron fully transferring to the boron system. There is clear charge transfer and the bond is effectively covalent.
Now, if we then look at ammonia, do we expect the lone pair on the nitrogen to transfer itself to the hydrogen atom of another ammonia molecule to form this hydrogen bond? If it corresponded to the boron example, then we would expect a change of at least several Debye units but as far as I know, there is no such change of dipole moment that is not explicable in terms of it being a condensed system. The article states there are experimental data to support charge transfer, but what is it?
Back to my original problem with computational chemistry: what role, if any, does theory play in modern chemistry? In this article we see a statement such as the NBO method falls foul of "basis set superposition error". What exactly does that mean, and how many chemists appreciate exactly what it means? We have a disagreement where one is accused of focusing on energies, while they focus on charge density shifts.  At least energies are measurable. What bothers me is that such arguments on whether different people use the same terminology differently is a bit like arguing about how many angels can dance on the head of a pin.  What we need from theory is a reasonably clear statement of what it means, and a clear statement of what assumptions are made, and what part validation plays in the computations.
Posted by Ian Miller on Apr 24, 2017 12:54 AM BST
Evidence requiring a change of paradigm?
An interesting thing happened for planetary science recently: two papers (Nature, vol 541 (Dauphas, pp 521 – 524; Fischer-Gödde and Kleine, pp 525 – 527) showed that much of how we think planets accreted is wrong. The papers showed that the Earth/Moon system has isotope distributions across a number of elements exactly the same as that found in enstatite chondrites, and that distribution applied over most of the accretion. The timing was based on the premise that different elements would be extracted into the core at different rates, and some not at all. Further, the isotope distributions of these elements are known to vary according to distance to the star, thus Earth is different from Mars, which in turn is clearly different from the asteroid belt. Exactly why they have this radial variation is an interesting question in itself, but for the moment, it is an established fact. If we assume this variation in isotope distribution follows a continuous function, then the variations we know about have sufficient magnitude that we can say that Earth accreted from material confined to a narrow zone.
 Enstatite chondrites are highly reduced, their iron content tends to be as the metal or as a sulphide rather than as an oxide, and they may even contain small amounts of silicon as a silicide. They are also extremely dry, and it is assumed that they were formed at a very hot part of the accretion disk because they contain less forsterite and additionally you need very high temperatures to form silicides.
In my mind, the significance of these papers is two-fold. The first is, the standard explanation that Earth's water and biogenetic material came from carbonaceous chondrites must be wrong. The ruthenium isotope analysis falsifies the theory that so much water arrived from such chondrites. If they did, the ruthenium on our surface would be different. The second is the standard theory of planetary formation, in which dust accreted to planetesimals, these collided to form embryos, which in turn formed oligarchs or protoplanets (Mars sized objects) and these collided to form planets must be wrong. The reason is that if they did collide like that, they would do a lot of bouncing around and everything would get well-mixed. Standard computer simulations argue that Earth would have formed from a distribution of matter from further out than Mars to inside Mercury's orbit. The fact that the isotope ratios are so equivalent to enstatite chondrites shows the material that formed Earth came from a relatively narrow zone that at some stage had been very strongly heated. That, of course, is why Earth has such a large iron core, and Mars does not. At Mars, much of the iron remained as the oxide.
In my mind, this work shows that such oligarchic growth is wrong and that the alternative, monarchic growth, which has been largely abandoned, is in fact correct. But that raises the question, why are the planets where they are, and why are there such large gaps? My answer is simple: the initial accretion was chemically based, and certain temperature zones favoured specific reactions. It was only in these zones that accretion occurred at a sufficient rate to form large bodies. That, in turn, is why the various planets have different compositions, and why Earth has so much water and is the biggest rocky planet: it was in a zone that was favourable to the formation of a cement, and water from the disk gases set it. If anyone is interested, my ebook "Planetary Formation and Biogenesis" explains this in more detail, and a review of over 600 references explains why. As far as I am aware, the theory outlined there is the only one that requires the results of those papers. So, every now and again, something good happens! It feels good to know you could actually be correct where others are not.
So, will these two papers cause a change of thinking. In my opinion, it may not change anything because scientists not directly involved probably do not care, and scientists deeply involved are not going to change their beliefs. Why do I think that? Well, there was a more convincing paper back in 2002 (Drake and Righter, Nature 416: 39-44) that came to exactly the same conclusions. Instead of ruthenium isotopes, it used osmium isotopes, but you see the point. I doubt these two papers will be the straw that broke the camel's back, but I could be wrong. However, experience in this field shows that scientists prefer to ignore evidence that falsifies their cherished beliefs than change their minds. As a further example, neither of these papers cited the Drake and Righter paper. They did not want to admit they were confirming a previous conclusion, which is perhaps indicative they really do not wish to change people's minds, let alone acknowledge previous work that is directly relevant.
Posted by Ian Miller on Feb 5, 2017 9:41 PM GMT
A Chem ArXiV?
The recent edition of Chemistry World had an article in which it was reported that the American Chemical Society is planning to start up a ChemRxiv, a preprint server. In this context, I note that chemists are strangely resistant to change, and the article was hardly overly enthusiastic about the concept. You probably know that the physics community has preprints on the ArXiV server, and by and large, physicists submit papers there for community peer review before submitting to a final journal. I started writing an article for this blog a little while ago on this topic, and never finished it, but this part of what I wrote. This, to me, makes a lot of sense, and a number of years ago some prominent chemists started up the Chemistry Preprint Server. The response from chemists was strangely disappointing. Very few submitted anything, and of those submitted, some were distinctly of low quality. Nevertheless, it seemed a good idea at the time. However, the main part of the chemistry community then proceeded to ignore it. Now I feel this should have been a great place for two things: getting an important paper into a form that the average community would accept, and secondly getting enough support for it that a journal would publish it. However, that preprint server did not work because very few were interested.
According to the Chemistry World article, the previous preprint server died because the quality of the publications was too low, and because the American Chemical Society would not publish anything that had been published before. That may be unfair on the ACS; I doubt it was unique in that. My belief is it died because most of the chemists of stature refused to take part, although in fairness at the time I also refused to put my experimental work on it because I was afraid that it would not be accepted later by the journal where most of my experimental work was then being published.
What are the purposes of a preprint server? One might be to get information out there earlier, but my feeling is that is not really that important in most cases. What I used the earlier server for was to archive material that was otherwise difficult to publish, and possibly get some idea what I could do to improve its acceptability.  Now, you might say, reading that, that I was a contributor to the "low quality" chemistry. Before jumping to such conclusions, consider these.
I submitted a logic analysis once to a chemical journal, the purpose was to show that the published data did not support the concept that the cyclopropane ring could delocalize electrons into adjacent unsaturated substituents. The standard position was it did, largely because it stabilized adjacent positive charge and gave bathochromic shifts to many UV absorptions, and extending the wave function would do that, as in the allyl cation. However, there is another way, namely a polarization field, i.e. the problem is one of electromagnetic theory rather than quantum mechanics. I wrote a logic analysis that showed not only did this alternative give correct predictions, but there were over 60 different types of experiment that falsified, or at least cast a lot of doubt, over the then accepted "delocalization" explanation. Note that demonstrating that cyclopropane stabilized adjacent positive charge 250 times still only adds one datum into a logic analysis. As a further aside, one previous review argued that quantum computations verified the presence of extra stability through delocalization. You may be amused to note that such computations used the same MO programs that "proved" the stability of polywater.
The first journal rejected it because they argued "it was not what the average chemist wanted to see" (or something like that). There were not enough diagrams (I assumed that a triangle headed towards a substituent X should have been general enough for many cases). One journal rejected the proposal "because this issue is settled". Who cares about the data and the logic? Others simply said they did not publish logic analyses. Fair enough in one way, but how could it get published? I will concede immediately that it could have been made easier to follow, but what I hoped was that chemists would tell me what it should have looked like to convince them. No such luck.
Similarly with a paper where I showed a pencil and paper route to getting a reasonably accurate estimate of the covalent bonds of the group 1 elements. That was rejected by editors because "nobody would be interested". They may or may not have been right, but the interesting point is it argued there was a hitherto unrecognized quantum effect applying.
Now some will say that was rubbish. Either it was right or it was wrong. If it were right, should it not be published somewhere? If it were wrong, should not someone be able to show where? And that is where a preprint server should be useful. It gives the scientific community the opportunity to comment and act as public referees, and takes away the ability to block something by editors who do not have to give excuses.
Posted by Ian Miller on Nov 3, 2016 9:44 PM GMT
The future for chemistry
The RSC should be complimented for its "Future of the Chemical Sciences" initiative, but this raises the question, is anything seriously missing from the output so far. I think the answer is, unfortunately, yes.
First, consider the four plausible scenarios. There is no doubt that chemistry will be needed to address many of the problems facing the world. That suggests there will always be a job for chemists, although not necessarily every type of chemist, so that is well identified, if not somewhat obvious. Of course some of the other options contradict this option.
The concept that we can have "do it yourselves" chemists where chemical processes that are stocked away in computers, and the future chemist can go to a "black box", key in what he wants, the computer tells him what feedstocks it needs, the chemist gets them, fills up some hoppers or whatever, presses "go", and waits for the product to come out, neatly bottled, might be plausible eventually, but this does not really require much in the way of chemistry, and it suggests there is not much future for synthetic chemists. This, to me, is an invitation to disaster, because like it or not, you should understand what you are doing. How many tragedies would there have to be before people were stopped from making something that was highly dangerous?
The third option, "no chemists" speaks for itself, and it is interesting that it focuses on "no new fundamental research". The free market chemistry option simply focuses on funding, and on all funding coming from the private sector. Neither of these options offers much hope for chemistry making our future better.
What do we note about these scenarios? What I see is a fixation on solving immediate problems, with the top problem being jobs for emerging students, and the implication is that current education, etc., is unsuited for purpose. How did we come to this? As far as I know, the major problems we face now have arisen largely because people with little knowledge of science have been at the helm, and the free market has let them at it. Exactly how will the free market solve the problems of climate change or pollution when it is the financial interests of certain players to keep doing what is counterproductive? The only thing stopping them now is regulations, and the voice of those who know. If nobody knows, where then?
What I notice is missing is the concept of trying to understand our discipline. There is no doubt that experienced chemists in a small section of chemistry know all about that small section very well, although whether it is understanding, or more the ability to recall what happened last time something like this was tried, is another matter. I have this feeling that chemists have now become very keen on "how to do something", but seem to have lost the spirit of discovery, wherein we might ask, why does x, y, z happen? Am I right? Who stands up and confesses they want to understand the basis for what they are doing? I do, but how many others are there? I recall earlier in the year I put up a blog post that raised the issue that maybe the energies of the A – B molecules of the group 1 elements were additive for their component atoms. That verges on heresy, and despite the evidence it may well be wrong, but nobody said a thing. So, what I would like to see is at least a little encouragement for understanding. After all, chemistry might be the first science to have all its fundamentals settled. We know all of chemistry is determined by quantum mechanics and electromagnetic theory. Why don't we want to use these a little more deeply?
Finally, here is a little example problem. In my novel, "A Face on Cydonia" the story needed small amounts of powerful explosives, so I "invented" a molecule: tetranitrotetrahedrane. My argument was that apart from its propensity to turn itself into carbon dioxide and nitrogen gas with serious vigour, it would be one of the more stable tetrahedranes. Can you guess why that might be? Or why I think it might be? Then, do you want little black box synthesizers in the hands of some of the terrorists who seem to want to go around blowing stuff up?
Posted by Ian Miller on Oct 2, 2016 10:46 PM BST
Brexit procedure
Far away, on the other side of this planet (in New Zealand, to be precise) we have watched the Brexit issue with a sort of stunned puzzlement. Why on Earth did this happen? And more to the point, now it has happened, why is it unclear what to do next? Even when trying an experiment, my view is you think out what you expect to happen, what you have to do to make it happen, then you try. It does not always work out correctly, because sometimes the molecules decide to be perverse, but I can't recall ever doing an experiment where I did not know what I wanted from it.
With Brexit, it seems the opposite has happened. Britain did it, and the question now is, now what? All of which raises an interesting question for the scientific community: you are trained to ask questions relating to procedure, so why did nobody or no organization stand up and demand to know from those advocating exiting what the consequences of exiting were? Why is it that that a vote was organized, but nobody knew the pros and cons of each position? Why is an informed vote something to be avoided?
All of which raises the question, where now for UK science? Presumably it will be out of major EU projects, although in principle there is no reason why that aspect of cooperation with the EU cannot continue. Perhaps the biggest single problem is immigration. Restricting immigration from the East seems to have been a major reason why the exit vote won, but when Switzerland as an associate began to impose immigration restrictions, it had that status suspended from Horizon 2020. The EU has to remain consistent, and since immigration was a major cause of the vote, the UK government is effectively ignoring the voters if it goes back on that. Chemists may feel that such ejection is no bad thing because chemistry mainly avoids big projects. It is physics that has the LHC, and ESA. I would hope that that sort of attitude is voided, and chemists, and the RSC, start lobbying for science as a whole, and not an insulated part.
Posted by Ian Miller on Jul 11, 2016 4:13 AM BST
The value of Theory overstated
In the recent Chemistry World, we read the heading "Technetium carbide refuted; proof that the compound cannot exist after all". The article then goes on to show that a team of computational chemists made calculations and showed that the carbide cannot exist, and what experiment had shown was there is a new phase of the metal.
 
Sorry, but that is just plain wrong. Not the calculations, necessarily, which may or may not be correct. The point is, you cannot prove anything by theory. One of the most successful theories of all time, in my opinion, was Newtonian mechanics, and when used to calculate the orbit of Uranus, observation failed to match the calculations. Either the theory was wrong or it was not, but whatever, nobody argued that the theory was right and observation wrong. The only way out was to postulate a new planet and Neptune was discovered. That was a triumph for theory. It put observable facts into the theory to predict something new, and there it was. However, when Newtonian mechanics was used to calculate the orbit of Mercury, observation failed to match the calculations. Again, either the theory was wrong or it was not, but whatever, nobody argued that the theory was right and observation wrong, and worse, no new planet could fix this problem. In the end, it was found that Newtonian mechanics is merely a good approximation to Einsteinian relativity.
 
As far as I am concerned, I have no idea whether technetium carbide exists. I know manganese carbide exists, and I know it is not especially resistant to certain reagents, so it is easy to make it and then lose it. Because of the nuclear instability, I doubt anyone really worries too much about technetium carbide, because it is extremely unlikely to be of significant use, but that does not matter. Further, the failure to make something in a synthesis does not prove the compound does not exist, but merely that is not the way to make it. There are an awful lot of unstable compounds that can be made, if you know how to go about it. As an aside, from my experience with manganese carbide, you may be better off not starting with the metal, as then that new metallic phase is far less likely to form.
 
As for the calculations, the best theory can do is make predictions. Only Nature can tell us whether they are correct. For me, calculations help us know we understand nature, but you cannot use calculations to prove something. All you can say is, if my theory is correct, then this is what you should expect.
Posted by Ian Miller on May 23, 2016 5:08 AM BST
Should we do something about climate change?
By now it is apparent that either chemists are not reading these posts, or they are not interested in evidence suggesting bond strengths are additive, or why, sometimes, they are not.
I must change my approach.  In the most recent Chemistry World there is a comment on climate change. What we see is that two proposals have been made to reduce carbon dioxide levels. One is to introduce crushed silicates into soils. Of course, they have to be the right silicates. One that has been proposed is peridotite. Most certainly, the earth is not short of this; it makes up most of the mantle, but of course the mantle is somewhat difficult to access, and we wo0uld have to deal with outcrops that have reached the surface.
The problem with this proposal is the rate of reaction. Some rocks weather tolerably quickly but overall the process is slow. It can be accelerated by at least a million times by injecting carbon dioxide into a suitable fractured rock layer, but that requires a lot of energy. This sort of proposal depends on sufficient of the right silicates being available, and the energy demands on the processing not generating, either directly or indirectly, more carbon dioxide than is removed. One problem is the source of the rock; if you can find it on the surface, obviously it is not reacting very quickly.
A more straightforward method suggested was to greatly increase afforestation. One point noted briefly in the article was that such forests might generate unintended consequences. Does not the logic of this comment grate a little?
First, huge amounts of forest have already been cut down. Allowing them to regrow would merely return the system to where it was before. A particularly good area to let re-develop would be the tropical rain forests. Huge areas of Brazil have had their forests removed, and the land is not that useful for anything else, so it tends to lie barren or be eroded. Replanting the forest, or simply stopping cutting it down and letting it regrow and spread would be a start.
One scheme that I think is worth further consideration is ocean fertilization, to let algae grow. There are two forms of algae: micro and macro algae. Microalgae grow simply with modest fertilization, usually with iron containing materials because the ocean waters away from the coast are remarkably deficient in certain cations. This proposal has been examined, and rejected because it was argued that only a minor part of the algae sunk to the depths and thus would be taken out of circulation. That, to my mind is ridiculous. What happened to the rest? Some, at least, would be eaten by fish and if we helped the fish population regenerate, would that be such a bad idea? Similarly, in the 1970s the US Navy showed that macroalgae could be grown in deep water on rafts, fertilized by sucking up water from the depths using wave power. The experiment ran into trouble during a major storm, and the consequent drop in oil prices killed it, but it might still be worth while. Some algae are the fastest growing plants on the planet, and as I have argued in my ebook "Biofuels", it is reasonably straightforward to make biofuel from it, which would replace fossil oil.
But for me, the biggest problem with the logic of "unintended consequences" is we are going to see some really major unintended consequences. There is a possibility of a sea level rise of up to 60 meters, as a consequence of our fossil fuel consumption. London sits between 5 and 30 meters above sea level. Is not drowning London an adverse consequence? Check with Google Earth, and if you live somewhere near the coast, your descendants may not be living where you live.
My view is the Society should be making as many efforts as it can to persuade various governments to invest more money into geoengineering research, and to coordinate it, because geoengineering alone can reduce the carbon dioxide levels in the atmosphere. What do you think?
Posted by Ian Miller on Apr 18, 2016 12:50 AM BST
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