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    This blog entry and all other text on this blog is copyrighted, you are free to read it, discuss it with friends, co-workers and anyone else who will pay attention.

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Urea nitrate

Dear Reader,

It has come to my attention that a man and his wife have recently been in court accused of the heinous crime of preparing a terrorist bombing. The explosive in this case is urea nitrate which is formed by the protonation of urea by nitric acid. As I have not heard of this substance before I looked its crystal strucutre. Yu.V.Nelyubina, K.A.Lyssenko, D.G.Golovanov and M.Yu.Antipin published a study of this compound which was published in CrystEngComm 2007, volume 9, page 991. The unit cell looks like this, you might think it does not look very interesting.

Unit cell of urea nitrate

Unit cell of urea nitrate

To get a true idea of what the solid looks like you need to grow this fragment and then trim off some atoms, then you will be able to see the hydrogen bonded layers.

Hydrogen bonded layer in urea nitrate

Hydrogen bonded layer in urea nitrate

When you look at the a different urea salt where the anion is hexafluorosilicate, you can see a different type of layer in the solid. Here the number of possible hydrogen bonds are smaller as there is a much lower charge to radius ratio of the anion. The anion is less coordinating. The layers here again like a chess board. Here is a picture of part of a layer.

Ball and stick version of urea hexafluorosilicate

Ball and stick version of urea hexafluorosilicate


Spacefilling version of urea hexafluorosilicate

The basic unit in this solid is a protonated urea which is hydrogen bonding to the hexafluorosilicate anion. Here it is in all its glory.

Hydrogen bonding between the protonated urea and the hexafluorosilicate

Hydrogen bonding between the protonated urea and the hexafluorosilicate


Small snail

Dear Reader,

I am sure that anyone who grew up in Sweden or has a child in Sweden will be aware of a song about a small snail. Which is about a snail being warned again and again. In Swedish it is “Lilla Snigel”.

I think that it is a sweet song, but it is one of those simple songs that can get stuck in you head (ear worm) and become irksome. I would be interested to know if someone is going to create a trance or techno version of it.

I am not sure of the origins of the song about the snail, I will have to ask my coworkers about it.

Ticket yourself ?

Dear Reader,

I was interested to read that in the USA a police officer stopped in a disabled space for a moment expecting another officer to then move his car for him. As the other officer failed to move it the car was parked wrongly in a disabled bay.

The policeman when he discovered this then ticketed himself. While I do not agree with the use of disabled bays as just for a moment stopping places, I have to say I am impressed by the fact that the policeman when his error was pointed out had the honesty to ticket himself and pay the fine.

IARC and meat

Dear Reader,

It has come to my attention that the international body which considers the evidence regarding the question of is agent X a carcinogen in humans has decided that red meat is probably carcinogenic to humans while processed meat is carcinogenic to humans. Now I imagine that lots of people have visions of doom in their mind, rather than looking at a nice beef burger or another meat ite m as a nice meal they might feel rather nervous about it. This terror is increased by comments such as those made in the Guardian which seems to equate meat eating with smoking and asbestos. I hold the view that the headline on the Guardian article is the product of either ignorance, laziness or some ideological desire to demonize meat eating.

The problem is that the IARC classes do not represent the level of the threat, they relate to the degree of scientific confidence regarding the question of “is agent X carcinogenic in humans” and not the question of “how carcinogenic is agent X”. This might to some people seem like an attempt to divide hairs but it is an important question.

We should consider some menacing IARC class one carcinogens, I will not go through all of them but here are some.

Estrogen (This is needed by women to maintain healthy bones)

Alcohol in drinks (This is a well known street drug but it is considered safe in small / moderate doses)

Sunlight (Well do not overdo it, while moderate exposure is unlikely to be dangerous it is best to wear sunblock if you will expose large areas of skin to daylight.)

Tamoxifen (this is an anticancer drug)

Now while these four substances I listed which are all class one, I can hardly say that they are all clear menaces to health and society. Maybe as another writer has commented it is time for the IARC to change the way they communicate with the outside world.

The problem is that to get into class one one of the best ways is for an agent to cause a rare form of cancer which can be spotted with ease. This form of cancer might result in very little human suffering is it is a very rare cancer, on the otherhand a more powerful carcinogen which causes a common form of cancer or a large number of common cancers will be much harder to spot. The reason why DES (Diethylstilbestrol) was spotted as a carcinogen was that caused a distinctive and rare form of cancer. It is interesting to note that in Sweden berylium (IARC class 1) is not strongly regulated under the carcinogen law while dimethyl sulfate and diethyl sulfate (IARC class 2a) are very strongly regulated by Swedish law.

Free speech at university sites

Dear Reader,

While I have never pretended that an absolute right to free speech exists, in general I hold the view that even those people who I disagree should be allowed to express their views. That is as long as their expression of their views does not harm society or the interests of others.

I was dismayed to see that Imperial College was not listed as a bastion of freedom of the thought and expression in a ranking of the freedom of speech at UK universitys. This caused me to examine the evidence, I found that the survey recorded Imperial College and Imperial College’s student union as having and environment “that chills free speech and free expression”. Sound scary !

I then found out the sins of Imperial College included the outrage of having a IT policy which includes an agreement not to

“display, store, receive or transmit images or text which could be considered offensive e.g. material of a sexual, pornographic, paedophilic, sexist, racist, libellous, threatening, defamatory, of a terrorist nature or likely to bring the College into disrepute.”

<Sarcasm>Shocking stuff !</sarcasm> But I have to say that such a policy is a reasonable one for a university, I think that it is unreasonable for the university to permit students to send, make and access such things. So I think that the people making the ranking of “free speech” at university sites have made a big error of judgement.

The student union’s safe spaces rules seem reasonable to me, a university student union which lacks such rules would be in my view unreasonable. A student union which does not outlaw violence, sexual harassment, discriminatory comments / behaviour and other forms of abuse would be a rather disturbing one.

Science education for youngsters

Dear Reader,

I took my two year old son to a science education centre today in Trollhattan in Sweden, he had a great time. But I noticed something. The centre had a vast number of physics and engineering experiments on offer, it had experiments on friction, transverse waves moving along a long spring, soap bubbles, mechanical experiments, energy conversion experiments (mechanical to electric to heat), optics, space rockets and toys such as marble runs but I could not find any chemistry experiments.

Also the experiments often had little explanation of why and how they worked, I would be more happy if the experiments each came with a short explanation of why and how they work. I think that while it would be a challenge to write an explanation of a physics experiment which a primary school child can understand it would possible and be a great addition to the experiments. I have a perfectly delightful home chemistry handbook from the 1940s, which sadly in common with many books aimed at the hobby chemist does not explain the theory of how and why the experiments work.

I think that chemistry has a scary and bad reputation which it does not deserve, the challenge is to dream up cheap and easy chemistry experiments which do not require hazardous reagents. I am sure that such experiments can be devised and put into action.

New SSM project, Lets make banish radiation accidents to science fiction.

Dear Reader,

It has come to my attention, and I imagine many of my readers attention, that radiation accidents feature on a regular basis in science fiction. Many science fiction tales have at their core some form of radiological misadventure for example the incredible hulk and spider man both were “normal” men until they were subjected to a dose of radiation or bitten by a radioactive spider.

I am sure that my readers will be glad to know that governments, university academics and other groups are working towards a world where horrid radiation accidents are only found in science fiction. As part of this effort the Swedish radiation protection authority (SSM) are supporting work in the Nuclear Chemistry unit at Chalmers. In this work the effects of chloride contamination on the release of fission products from fuel and the capture of organic forms of radioactive iodine onto charcoals is being investigated.

The chloride contamination issue became of interest during the Fukushima accident, in this accident sea water was used to cool the stricken nuclear reactors for some time. If the reactors had dried out a second time then nuclear fuel could have been exposed to molten salt. Some of my readers will be aware of the fact that metal chlorides tend to be more volatile than metal oxides. For example copper chloride is more volatile and is able to enter a flame where it generates green light. The effect of dichloromethane on the flame coming from a brass butane torch can be seen in the following film.

It is reasoned that if a similar process is able to increase the mobility of a fission product then a salt addition could increase the threat posed by a reactor accident to the public. Also this study could offer an insight into an accident in a chloride based pyro-reprocessing process using a molten salt such as a NaCl/KCl eutectic.

The other area relates to both sampling and personal/collective protection. One of the methods of measuring radioactive iodine in air is to use a Maypack filter. This is a device through which a large volume of air is sucked. After sucking the air the Maypack is dismantled and the different parts measured for radioactivity. It is possible to determine what chemical form the iodine was in when it reached the Maypack. Aerosols, elemental iodine, HOI and organic iodine all collect in different parts of the device. Methyl iodide is known to react with charcoals which are impregnated with chemcials such as potassium iodide and DABCO. However if an organic form of iodine which is unable to react quickly with KI and DABCO was to enter the charcoal pad in the filter then it could revapourise and be lost from the charcoal pad. As the organic iodine fraction is often a major part of the radioactive iodine released from a nuclear plant this could result in an underestimation of the amount of radioactive iodine released from a plant.

Also if the organic iodine compound is more able to pass through charcoal pads in respirators then it could cause the protection factor of a respiratory to be lower than that predicted by tests using methyl iodide which seems to be the de facto standard alkyl iodide used in nuclear safety experiments. We hope in this project to test the hypothesis that the DABCO loaded charcoal is able to capture all the organic forms of iodine which can form during an accident. This work is of interest to the ISO organization (ISO TC94 SC15 WG2&WG3 PG3 JTG CBRN) as the ISO organization is currently considering a standard for protective clothing for use in the nuclear / radioactivity sector.

Now while nuclear / radiological accidents are clearly not “fun” and are not joking matters, it is important to understand that the nuclear chemistry section at Chalmers is not a “Fun Free Zone” (FFZ). Years ago I read a chemistry laboratory manual which commented “Chemistry should be done while sober but not while somber”. A trip to a chemistry department should not have to be sad and unhappy, even those who toil in the nuclear chemistry section are allowed to share a joke, well that is as long as it is in good taste and on an acceptable subject.

Here are some of the people who work on nuclear accident chemistry eating gazpacho soup, now you might ask what is so funny about gazpacho soup. Well to understand the cultural significance of this soup to me you need to know of Red Dwarf.

Emma on the left and Mark on the right, both are enjoying some soup.

Emma on the left and Mark on the right, both are enjoying some soup.

One classic British comedy which is well known to people of my generation is Red Dwarf which is about the last man left alive in the universe, again in the first episode this sci-fi story features a radiation accident which I would rank being at least. INES level five (based on the death of the whole crew of a spaceship). Maybe it might be an INES level of six based on the large number of deaths.

One of the central figures (Rimmer) who is a rather disagreeable fellow died in the first series before returning as a hologram. His last words were “gazpacho soup” which relates to the event which he credited with ending his career. He sent the cold soup back in disgust in front of the ship’s captain demanding that it be heated up. In fact the pompous, officious and cowardly Rimmer was doomed to failure because of other matters.

He spends many hours with a more laid back man in this science fiction comedy often being the subject of many jokes. For years I was in blissful ignorance thinking that gazpacho soup was something invented by the script writers of Red Dawrf, while as a postdoc on a busniess trip to Spain years ago I saw it on the menu of a restaurant. I then tried it partly out of curiosity and partly as it felt funny to be eating the substance that troubled Rimmer so much.


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