Letters: March 2016

Make room for Moseleyium

The ratification of claims for the discovery of four new elements last December came at the end of the year which marked the centenary of the death of English physicist Henry Moseley in the Gallipoli campaign during the first world war on 10 August 1915. In a brief but mercurial research career lasting less than four years, he had established that it was possible to assign a number to each element based on the frequencies of the radiation emitted from elemental targets in an x-ray tube. He further proposed that what came to be known as the atomic number could be equated with the charge on the nucleus, and that this number determined the order of elements in the periodic table. These discoveries led to the identification of four missing elements between aluminium and gold. X-ray spectroscopy quickly gained an important role in assessing the veracity (or otherwise) of claims for the discovery of new elements. 

A campaign launched in 1925 suggested that the then missing element with Z=43 should be called moseleyum when it was eventually discovered. However, 12 years elapsed before the element was found, and in 1947 it was assigned the name technetium in recognition of it being the first artificial element. Despite his pivotal role in putting the periodic table in to its modern form, no element has ever been named after Moseley. Is it time to revisit moseleyum – or moseleyium – as the name for an element?

Russell Egdell CChem MRSC
University of Oxford, UK

Peter Edwards FRSC FRS
University of Oxford, UK

Eric Scerri 
UCLA, US

Big trouble with Tu in China

I read with interest the recent analysis of the reaction of scientists in China to the award of the 2015 Nobel prize in physiology or medicine to Tu Youyou for her work on the antimalarial drug artemisinin. This has stimulated more reflections and discussions on research in China, with many asking why the honour of China’s first Nobel prize went to Tu, who does not have a PhD or any overseas study or research experience, instead of other high-profile scientists.

In the article, Wu Yishan criticised the prevailing paper-based evaluation system used in China, observing it does not focus on innovation. I agree that the current system places too much emphasis on papers, impact factors and citations. These easily quantified ‘facts’ are particularly favoured by the administrators of various funding agencies and universities; however, this system is stifling curiosity-driven education and research.

Last October, shortly after announcement of Tu’s news, I went to my catalyst characterisation class, well-equipped with artemisinin crystal samples and seeds along with a book written by Tu, intending to impress more than 70 postgraduate students with the discovery story. I was frustrated to barely see an excited and curious face among them. Instead, what concerns them most is how to get high marks, publish papers and gain quick success.

I cannot agree more with Nobel laureate Elias Corey: ‘It has always been my view that one should try to do one’s very best in teaching and research, and accept any honours which are bestowed as good fortune. But should one’s research go unrecognised, one could always take pleasure in the accomplishments themselves and in the joy of discovery. To do research because it is interesting and useful to one’s fellow scientists and to society as a whole is vastly wiser than choosing a line of research simply because it is more likely to be rewarded.’ 

Certainly we have a long way to go in Chinese chemistry education and research.

Yang Gan FRSC
Harbin, China

Systematic shock

I notice that names are to be selected for the final four elements on row seven of the periodic table. I purchased a wall chart of the table last autumn where the new elements were shown with their systematic names, such as ununtrium and ununoctium. I am surprised that the great and the good have not tried to get us to use the systematic names for all the elements. 

This has already been done in organic chemistry (dimethyl ketone will always be acetone for me). However, I suspect that customers seeing a bottle of diunium monoctide on the shelf in their supermarket would be less likely to buy it (let alone drink it) than if it were simply labelled ‘water’.

Norman Groocock MRSC
Bakewell, UK 

Lignin’s smoky scent

I read with interest your article on smoking foods. However, I have to take issue with its broad description of the chemical make-up of wood. 

Cellulose and the hemicelluloses are sugar-based, as stated in the article. However, lignin is not a carbohydrate but a large, complex phenol propyl-based polymer. Essentially it’s what makes wood hard and acts as a cementing substance that holds the cellulose fibres together, although, to add to the complexity, it varies somewhat with plant types and species. Lignin will clearly be a part of the smoking process and, as such, it yields a multiplicity of aromatic compounds to the mix, contributing to the overall taste of the end product.

In addition, the article makes no mention of the so-called extractives of heartwood timber, which often characterise the species and must also contribute to the smoking process. These include a wide variety of organic molecules (such as tannins in flavonoids), mostly phenolic, some of which must be beneficial to the end flavour of the smoked product. Presumably, this is why oak timber in the UK is favoured for smoking. 

Recently, much has been made of the carcinogenic possibilities arising from smoked products. It would have been instructive if this topic had also been covered.

Reginald Orsler CChem FRSC
Prince’s Risborough, UK

Boron doesn’t blast off

I was most interested to hear about the new green rocket fuel developed in China using borohydride-rich ionic liquids. It evoked memories of my boron hydride research under Norman Greenwood at Nottingham University, UK, in the early 1960s. 

Boron hydrides had been tested as rocket fuels because their heat of combustion was 50% higher than the corresponding weight of a hydrocarbon fuel. Theoretically, this considerably reduced the weight of fuel needed to have the same range as conventional rockets. However, it was soon realised that one of the two products of combustion was boron oxide, with a melting point of 450ºC, which formed a glassy deposit. 

Not only did the rocket’s thrust perform below expectations as the products were not all gases, but some of the boron oxide deposited on the edge of the exhaust and eventually blocked the thrust entirely.

I hope that the much lower concentration of boron in this new fuel won’t have the blockage problems of the previous rocket fuel experiments with boron hydrides. As the current researchers are finding, boron hydrides are hazardous compounds which can cause severe neurological problems, as well as showing instability in oxygen and water.

Paul Roebuck CChem FRSC
Nottingham, UK

Keeping your (reactor) cool

I was interested to read Wylfa Magnox, the UK’s oldest nuclear power plant and last to use gas-cooled reactors, has closed. 

While water-cooled designs have become common, gas-cooled and other non-water cooled reactors offer an important advantage: the higher outlet temperature of the coolant (heat transfer fluid) enables the production of steam with a higher temperature. The use of hotter steam in a turbine can greatly increase the efficiency of the plant.

In water-cooled designs, a series of precipitates (crud) can form on the fuel during normal use. The crud on boiling water reactor fuel is hematite (a-Fe₂O₃) and black spinel (M_xFe_3–xO₄), while grey spinel (Ni_xFe_3–xO₄) tends to form on pressurised water reactor fuel. The metals in the crud can become neutron-activated before migrating to other parts of the primary cooling loop. Here, the deposited radionuclides can increase worker dose during servicing. In a gas-cooled reactor this process, which causes radioactivity to migrate, does not exist. This could make servicing easier in a gas-cooled reactor.

One advantage water-cooled reactors have over the graphite designs is that the moderator can be changed with ease. One limitation on the life of a reactor is the neutron irradiation of the reactor’s pressure vessel; water-cooled reactors protect this with a layer of water. On the other hand, an important limiting factor for the graphite or gas reactors is the corrosion of graphite by CO₂, which forms CO. As the core of a magnox plant is a series of interlocking graphite blocks it is not possible to change the moderator and thus extend the life of the reactor.

Mark Foreman CChem MRSC
Chalmers University of Technology, Sweden

Let’s dance

I enjoyed the news item on the ‘Dance your PhD’ competition, where chemists were using the medium of interpretive dance to describe their research. It is a shame there were only five entries in the chemistry category. 

Surely we could improve on that figure? Perhaps we could start by asking any PhD chemists we know to dance their work retrospectively, maybe during breaks or in the work canteen?

Ian Brooks 
Fife, UK