Chemistry

2D becomes 3D with pen

A pen as a 3D printer. Watch a 2D drawing of a flower on a stone turn into a three-dimensional flower after immersion in a solution of potassium persulphate.

3D pens have been around for some time. They form a kind of hand-held 3D printer, fed with a roll of 3D filament that can be used to draw shapes in the air.

This technique works differently, with two types of material. One type, the 'glue' (here: the black ink), adheres to both the substrate and the second type. The second type, here red, contains a water-repellent agent and therefore detaches when the solution squeezes under the ink.

In its original form, the ink was too weak and the object lost its shape. The inventors remedied this by adding iron to the water-repellent ink. This reacts with the persulfate ions in the solution and forms a hard layer on the outside. Thanks to this layer, the flower retains its shape.

Colleagues elsewhere in the world of South Korean inventors Sumin Lee and Seo Woo Song call the discovery a breakthrough. It is now possible to send 3D objects by letter post. The recipient can place these in a development solution and let the 3D object dry. They also see many applications for the manufacture of electronics. That is, if it succeeds in printing electronic circuits.

And for creative artists of course.

This is just a simple example. The source contains much more complex designs. Such as butterflies that can flap their wings under the influence of a magnetic field.

Source

Sumin Lee and Seo Woo Song, Direct 2D-to-3D transformation of pen drawings, Science Advances, 2021

Nitrogen auction with emission rights solution for nitrogen problems

The Netherlands is a small, densely populated country with an extensive livestock population. That does not go well together. Naturally low-nitrogen nature reserves are increasingly dying. Is a nitrogen auction the solution?

Why is nitrogen a problem?
Just under eighty percent of the Earth's atmosphere consists of nitrogen gas (N2). Nitrogen is an indispensable element for life. We consist of proteins and proteins from amino acids, a nitrogen compound. The Netherlands contains millions of nitrogen sources, ranging from pets to pig fattening, and of course you, dear reader. Car traffic and construction activities also emit nitrogen, albeit much less than people and especially fattening farms. In the nitrogen discussion, we mean all nitrogen sources, other than atmospheric nitrogen and nitrogen bound in proteins. These are mainly ammonia (NH3) and nitrogen oxides (NO, NO2 and the controversial laughing gas N2O). Nitrate (NO3-) that washes out of fertilized fields is an environmental problem.

Nitrogen emissions in the Netherlands have already fallen enormously, but unfortunately insufficient for the new strict EU standard. Source: [2] [3]
Brutal construction freeze due to an administrative emergency
The EU has enacted strict rules for nitrogen emissions. Rules that are easy to enforce in a sparsely populated country such as France or Bulgaria, but very difficult in the Netherlands. The problem is not that nitrogen emissions in the Netherlands are increasing. On the contrary. This has fallen considerably, partly due to strict laws and regulations such as the mineral accounting for farmers [2] [3]. The problem is that partly due to the appalling lack of foresight by the Rutte cabinet, emissions did not fall quickly enough. As a result, a building freeze was declared with significant economic damage - and a continuation of the housing crisis.

Nitrogen Auction: Pros and Cons
The free market is very good at finding the economic optimum. This can be an advantage, at least if the scope of the free market is limited in such a way that no externalities occur. Creating externalities happens quite quickly. For example, clever entrepreneurs started breeding muskrats themselves, when the government put a premium of ten guilders on each rodent killed. In principle, the government can sell the right to emit nitrogen, for example, through a nitrogen auction. If a pig farmer quits, he can sell his emission rights through the auction to another farmer, to a builder or a nature organization (which then does not use them). At a certain point, the entrepreneurs who can earn the most euros per kilo of nitrogen emissions hold the emission rights, creating an economic optimum. According to the school booklet economics.

Any system of laws and regulations involving money has the potential for fraud. Nitrogen emissions take place in the form of gaseous compounds. Gases are notoriously difficult to trace from a single source. For example, a farmer can report that he has installed an expensive capture installation that he does not actually have, or a much worse cheaper model, which means that his emissions are much higher than official figures show. It is therefore necessary to check thoroughly here, preferably also with regular field measurements in the vicinity of major nitrogen pollutants. On balance, this system is therefore feasible.

Sources
1. Emissions authority: give nitrogen rights trading a second chance, FD, 2019
2. Acidification and large-scale air pollution: emissions, 1990 - 2017, Center for the Living Environment, 2017
3. O. Oenema, Fact sheet nitrogen sources, Wageningen University, 2019

Is Inorganic Life Possible?

Carbon compounds are called organic compounds in chemistry. This is not for nothing. Carbon is indispensable for life. The carbon chemistry is unimaginably rich. There are more compounds with carbon than all known compounds without carbon. But what if, for whatever reason, there is no carbon in a certain place, but other elements and energy? Or if not even chemistry as we know it is possible? Could life form in that place? The answer: maybe, although the chances of this are not very high as far as we know. Below one overview with the, mainly speculative, knowledge we have acquired at this time.

In a breakthrough in 2017, researchers discovered something remarkable. With the help of directed evolution, they were able to convert an enzyme of the bacterium, Rhodothermus marinus, into an effective catalyst for the formation of bonds between carbon and silicon. A bacteria capable of processing silicon proves that it is theoretically possible for partially silicon-based life forms to exist. this video.

Work by Caltech researcher Frances Arnold proved that it is possible for bacteria to use silicon. And that life is conceivable partly based on silicon. Source: Caltech

At present there is no ecological benefit to such life forms on Earth, but on worlds much hotter than Earth, such as Venus, silicon-based life forms may have the advantage. Silicones and other silicon compounds are sometimes more resistant to high temperatures than carbon compounds. And silicon is just the beginning of the possibilities ...

Source
Frances H. Arnold et al., Directed evolution of cytochrome c for carbon – silicon bond formation: Bringing silicon to life, Science Magazine, 2016 (DOI: 10.1126 / science.aah6219)

 

Isotope separation with cage molecules brings nuclear fusion closer

Deuterium, an important raw material for nuclear fusion, is now difficult to extract and therefore expensive.

Back in the eighties of the last century, it was big news: the existence of buckyballs (C60), football-shaped carbon molecules. With the discovery of buckyballs, the concept also arose that atoms, ions and small molecules could be trapped in this “cage”. Since then, things have been quiet around buckyballs and similar molecules. Only graphene and carbon nanotubes should enjoy continued interest. Now there appears to be a spectacular new application. Deuterium is needed for nuclear fusion. This differs from the most common form of hydrogen because there is not only a proton, but also a neutron in the nucleus. About one of the 6240 hydrogen atoms is a deuterium atom. (There is also a third hydrogen isotope, tritium (perhaps known from the 'tritium lights'), a radioactive variety with a half-life of just over ten years. Tritium is therefore almost non-existent by nature).

Separating deuterium from protium, 'normal' hydrogen, is a laborious process: both isotopes are chemically almost identical. It is true that because of the double mass, deuterium is slightly slower in chemical reactions than protium, and high concentrations of deuterium are in the body (think of many percentages of all hydrogen) toxic, but this difference is not very great. Very annoying, because now both isotopes have to be separated from each other using expensive techniques, such as gas diffusion. Pure deuterium currently costs several thousand euros per kilogram.

This new technique may change this. The special molecular structure of the separator layer - with strategically placed large and small cavities - accelerates the heavier deuterium particles compared to the protium particles. This creates an enrichment in deuterium in the concentrate. If this step is repeated often enough, a very deuterium-rich concentrate will eventually be formed. Once deuterium makes up a high percentage of the concentrate, it is much easier to boost the deuterium content even further.

Deuterium is the heavier version of hydrogen. Deuterium is rare: only 1 in every 3,200 hydrogen atoms on Earth is a deuterium atom. Source: dancingwithwater.com

The technique used only works at temperatures that are about thirty degrees above absolute zero. The researchers hope to develop a variant of the isotope separation that can also be used at higher temperatures.

Source:
Ming Liu et al. Barely porous organic cages for hydrogen isotope separation, Science (2019). DOI: 10.1126 / science.aax7427

Direct air capture: the CO2 economy is now really going to break through

Carbon dioxide is a controversial greenhouse gas and is often demonized. Increasingly, CO2 is now being used as a carbon source. Does direct air capture (DAC) solve both the fossil fuel problem and man-made global warming?

Carbon dioxide, a gas with two sides
Carbon dioxide is a dreaded greenhouse gas, but aside from this, carbon dioxide is a valuable and inseparable part of the Earth's ecosystem. From a plant standpoint, humanity has brought a welcome end to a dire one CO2 famine. Carbon is an indispensable element in living organisms and industry. Carbon atoms can form four stable covalent bonds, both with highly electronegative elements such as oxygen and with electropositive elements. Carbon has the richest chemistry of all elements. Carbon chains therefore form the backbone of fats and carbohydrates and are also indispensable in amino acids, the building blocks of proteins.

The main branch of chemistry, organic chemistry, deals only with carbon compounds. At present, the main source of carbon is petroleum. Until now, petroleum, with natural gas and the hard-to-handle coal, was the cheapest alternative. That now seems to be changing. The reason: DAC.

What is direct air capture?
Our atmosphere consists of 78% nitrogen, 21% oxygen and 1% argon, a noble gas. Carbon dioxide makes up 0.04% of our atmosphere. Direct air capture distills carbon dioxide from the air. The traditional but high energy method is to compress and cool air to the sublimation point of carbon dioxide: -78 degrees at atmospheric pressure. A lot of research is currently being done into special filters and chemicals to selectively filter carbon dioxide from the air. The theoretical maximum efficiency for this process is 250 kilowatt hours per ton of CO2 extracted. That is an extremely high amount of energy: the energy bill of an average family for a season, or, in other words: to generate this 250 kWh, 125 kg of CO2 is released with gray electricity. And we are talking here about a theoretical optimum: more energy is needed in practice. Until recently, this was an insurmountable barrier for DAC, but the advance of cheap solar energy and smarter separation techniques now makes DAC interesting. [1]

Climeworks is one of the companies that is now strongly committed to CO2 extraction from the air. Source: Climeworks

What do we do with this CO2?
Some companies pump water with this CO2 into a subterranean CO2-absorbing layer, such as porous basalt, in which the carbon dioxide mineralizes. With this the CO2 is indeed effectively stored. Others use the CO2 as fertilizer for gardeners (under high CO2 concentrations, yields increase by 25% or more) or for carbonizing soft drinks.
In fact, this is just the beginning of the possibilities. In principle, carbon dioxide can be converted into simple organic molecules such as methanol [2] or ethanol. Graphene. Diamond. Or perhaps biochar, powdered charcoal that allows the soil to retain water and nutrients better. Once we have abundant energy, the possibilities are almost endless.

Sources
1. M. Fasihi et al., Techno-economic assessment of CO2 direct air capture plants, Journal of Cleaner Production
Volume 224, 1 July 2019, Pages 957-980, DOI: 10.1016 / j.jclepro.2019.03.086
2. Xiaowa Nie, Xiao Jiang, Haozhi Wang, Wenjia Luo, Michael J. Janik, Yonggang Chen, Xinwen Guo, Chunshan Song. Mechanistic Understanding of Alloy Effect and Water Promotion for Pd-Cu Bimetallic Catalysts in CO2 Hydrogenation to Methanol. ACS Catalysis, 2018; 8 (6): 4873 DOI: 10.1021 / acscatal.7b04150

‘Moleculair zwart gat’ gecreëerd met extreem krachtige röntgenlaser

Een onderzoeksgroep van SLAC (Stanford Universiteit) slaagde er in om een ‘moleculair zwart gat’ te creëren in een klein molecuul. Goed nieuws dus voor medicijnontwikkelaars en andere chemici, en hiermee ook ons.

Stel je voor: alle zonlicht dat de aarde bereikt, geconcentreerd in een gebiedje ter grootte van een peperkorrel. Dit is de intensiteit die gedurende 30 femtoseconden bereikt werd met de röntgenlaser die voor dit experiment ingezet werd, de Coherent X-ray Imaging instrument, CXI. De laserbundel van de CXI werd geconcentreerd in een gebiedje met een doorsnede van 300 nanometer.

De gebruikte harde röntgenstraling heeft een energie per foton van 8300 elektronvolt. Ter vergelijking: licht heeft minder dan 2 elektronvolt energie per foton. 8300 elektronvolt is de ionisatie-energie van de twee elektronen in de (binnenste) K-schil van een jodiumatoom, precies voldoende om deze selectief weg te slingeren. .

Deze bundel werd afgevuurd op xenonatomen en van jodiumatomen die onderdeel uitmaakten van een klein molecuul, methyljodide (CH3I). Zoals verwacht, werden de elektronen van de binnenste atoomschillen totaal gestript. Het atoom werd als het ware uitgehold. Daardoor ontstond er een enorme zuigkracht van de positief geladen atoomkern naar de rest van de elektronen in het atoom. Omdat dit binnen femtoseconden gebeurt, werden ook deze elektronen door de laserbundel weggestript tot het molecuul, dat bijna alleen nog uit positief geladen atoomkernen bestond, explodeerde.

Een moleculair zwart gat slorpt alle elektronen op en spuwt ze uit. Bron: SLAC

Onverwacht was dat er minimaal 54 elektronen werden weggeslingerd uit het jodiumatoom. Het atoomnummer van jodium is 53. Dit betekent dat ook elektronen uit het nabijgelegen koolstofatoom, en mogelijk ook de waterstofatomen betrokken werden in de cascade. Dit had dus veel weg van een moleculair zwart gat, waarbij de positief geladen atoomkern van het jodiumatoom alle elektronen in het molecuul aantrok. Een opmerkelijk technisch staaltje, waarmee het research team het befaamde wetenschappelijke tijdschrift Nature wist te halen.

Sloopwerk is natuurlijk altijd een interessant doel op zich, maar de voornaamste wetenschappelijk waardevolle uitkomst is hier dat het measured pulse model het juiste blijkt te zijn, niet het concurrerende Gaussiaanse pulsmodel. De voorspellingen van het measured pulse-model bleken tot op 2% nauwkeurig. Goed nieuws voor bijvoorbeeld medicijnontwikkelaars, die nu veel nauwkeuriger het gedrag van moleculen kunnen voorspellen. Ook dient dit experiment als voorbereidend werk voor een belangrijke upgrade van de laser. Hiermee kunnen tot 1 miljoen pulsen per seconde worden afgevuurd (nu 250 per seconde).

Sources
1. The World’s Most Powerful X-ray Laser Beam Creates ‘Molecular Black Hole’, SLAC Communications, 2017
2. A. Rudenko et al., Femtosecond response of polyatomic molecules to ultra-intense hard X-rays, Nature (2017). nature.com/articles/doi:10.1038/nature22373

Pomegranate precursor life-extending substance urolithin A.

De stof urolithine A, die door micro-organismen in de darm uit granaatappel wordt gemaakt, vertoont levensverlengende effecten bij twee diersoorten, waaronder muizen. Dit maakt de kans groot, dat een dergelijk effect ook bij mensen optreedt, aldus de onderzoekers.

Levensverlengend effect van urolithine A

Ontdekker Johan Auwerx met een granaatappel. Micro-organismen produceren het levensverlengende urolithine A.

Urolithine A wordt door micro-organismen gevormd uit stoffen zoals elligatannines en in het bijzonder punicalagines, die in granaatappels voorkomen. De effecten van urolithine A bleken opmerkelijk. De stof verlengde de levensduur van het wormpje Caenorhabditis elegans, wegens zijn korte levensduur massaal in laboratoria gekweekt, met maar liefst 45%. In absolute termen een dag of vier, want C. elegans is al na tien dagen bejaard. Ook in muizen bleek het effect sterk. Laboratoriummuizen worden doorgaans niet ouder dan twee jaar. De groep die met de stof werden behandeld, deden het qua uithoudingsvermogen 42% beter dan de controlegroep.

Hoe werkt de stof?

Auwerx en de zijnen gingen niet over één nacht ijs. Toen ze het levensverlengende effect op C. elegans hadden vastgesteld, probeerden ze het exacte mechanisme te achterhalen door alternatieven uit te sluiten. Zo bleek het niets te maken te hebben met bacteriën in en rond de worm: zelfs bacterievrije samples toonden het effect. In vervolgonderzoek testten ze diverse genetisch gemanipuleerde varianten van de worm. Bij alle varianten trad het levensverlengende effect op, behalve bij de variant met gebrekkige mitochondrieën (kleine celonderdelen die ooit zelfstandig levende bacteriën waren. Deze ‘energiecentrales’ produceren de energiedrager ATP uit ADP en fosfaat met behulp van de energie uit de reactie van zuurstof en glucose). Verder onderzoek bevestigde dit beeld: het levensverlengende effect trad uitsluitend op door het effect op de mitochondrieën.

Ze waren duidelijk iets groots op het spoor en enthousiast gingen ze verder. Uit vervolgonderzoek bleek dat urolithine A gebrekkige mitochondriën opruimt (mitofagie), waarna zich jonge mitochondrieën vormen. Dit mechanisme bleek zich ook in zoogdiercellen voor te doen.
In een vervolgexperiment op muizen bleken de jonge, gezonde mitochondrieën het uithoudingsvermogen van de oudere muizen sterk, met bijna de helft, toe te laten toenemen.
Uit de proeven bleek ook dat het niet nodig is om dit supplement gedurende het gehele leven te slikken. Met urolithine A behandelde muizen begonnen vrijwel direct met de mitofagie en aanmaak van verde mitochondrieën.

Hoe kan ik deze resultaten zelf toepassen?

Het goede nieuws is dat urolithine A door onze darmflora wordt aangemaakt als we granaatappels eten. Dit verklaart dan de ervaringen van veel mensen dat granaatappels ze nieuwe energie geven. Helaas geldt dit niet voor alle mensen. De reden is dat hun darmflora niet de essentiële bacteriesoort bevat, of dat de stof niet door hun darmwand wordt geresorbeerd.

De structuurformule van een molecuul Urolithin A

Enkele leden van de onderzoeksgroep zijn daarom een startup begonnen die urolithine A gaat produceren.
Kortom: vaker, het liefst elke dag, granaatappels eten zal zeker helpen totdat hopelijk snel  de eerste urolithine A supplementen op de markt verschijnen. Als je darmflora de juiste bacteriën bevat.

Source
Urolithin A induces mitophagy and prolongs lifespan in C. elegans and increases muscle function in rodents, Nature Medicine, DOI: 10.1038/nm.4132

Analog computer makes a comeback

Analog computers are out. All computers we know from everyday life are digital computers. Quantum computers are increasingly in the news. Now the analog computer with its own programming language has become much more user-friendly. Will there be a comeback?

What Are Analog Computers?
Computers are devices that calculate, more broadly: process information. That can be done in different ways. The computers we know from everyday life use two voltage levels, which are interpreted as 0 and 1. These digital computers are much faster in processing exact numbers than other types of computers. They are also easy to program. No wonder, then, that we have been using digital computers en masse for two generations now, and not analog computers such as slide rules.

Analog computers are an analogy (corresponding structure) of a system on which they perform calculations. In fact, it is better to speak here of a measurement than of a calculation. In the 1950s, Statistics Netherlands used an impressive pipe system to practice the pseudoscience of economics. This analog computer worked through the principle of communicating vessels. Below a video with a surviving copy of such a thing, the MONIAC.

In fact, some issues are easier to deal with with an analogue than with a digital computer. A differential equation, for example, is difficult to express numerically. It costs a digital computer many calculation steps with algorithms like Runge-Kutta to determine the outcome of a differential equation. In principle, this can be done almost immediately with an analog computer, regardless of how complicated the differential equation system is. Most often, an electronic analog computer is used for this. The change of an electric current (ie the differential) generates a magnetic field. The more change, the stronger the magnetic peak. Measure that magnetic field with the desired accuracy and see, there is your answer in a split second, while the digital computer still sighs and groans.

AKAT-1, an analog computer. Once state of the art. Will analog computers make a comeback again? Source: Wikimedia Commons

Programming until now is a bottleneck
This sounds too good to be true and it is. The main bottleneck for the analog computer is the enormous effort it takes to program this jewel. In the 1950s, there was simply no other choice, but now differential equations can easily be found in programs like Maple or Mathematica, or for the less specially blessed, the open-source alternative. Sagemath, to be imported. Digital computers are so fast that even the cumbersome digital way still produces quick results. Even though really extensive systems, such as those you need to mimic complex biological systems, still take a lot of computing time. It is not without reason that many scientists are still eagerly looking at the possibilities of analog computers.

What are Derivatives and Differential Equations? What can you do with it?
Differential equations describe the relationship between a function, f (x) and the derivative of a function, f '(x). In normal human language: between the function and the rate of change of a function. If you know how a function behaves, you can predict its behavior.

Logistic (sigmoid) curve. Source: Wikipedia

There are many growth processes, for example that of a market, that behave as so-called sigmoid, an s-shaped function. The derivative of this s-shape is the well-known clock function or normal distribution, a hill around the zero point. If you want to be active in a market as a starting entrepreneur, it is smart to choose a market that is growing faster and faster. In other words, whose derivative grows. When this growth rate slows down, the competition becomes fierce and your chances are slim. I saw a graph of the more developed German market at a multilevel marketing company in the Netherlands and recognized the sigmoid. So I no longer believed the jubilation stories about the Dutch market, which formed the beginning of the sigmoid. This, I could deduce, would inevitably stagnate as well.

With a single differential equation you can, for example, describe very nicely physical fields. Groups of differential equations represent the interaction in a more complex system, such as a body cell or a chemical reactor. If you can predict the behavior of these differential equations, you know the system and the behavior of the system. And, knowledge is power.

Programming language for analog computers
Some of those people who are tired of the limitations of digital computers are Prof. Martin Rinard of the American top university MIT and former colleague Rahul Sapeshkar, who developed an analog chip with a number of doctoral students. This allows analog calculations to be performed. The chip can be programmed and read by means of a digital computer. They have developed a programming language for this chip (and similar chips) for this purpose.
In Arco, the programming language of the group of researchers, differential equations can be easily applied. It takes about a minute to program each differential equation. Even a complex system of seventy differential equations can be entered and compiled in about an hour. As with all analog computers, the results are basically known almost immediately.
A supercomputer can be replaced with a simple chip. At least: for these kinds of simulations.

Source
Sara Achour, Rahul Sarpeshkar, and Martin Rinard, Proceedings of the 37th ACM SIGPLAN Conference on Programming Language Design and Implementation (PLDI 2016), Santa Barbara, CA, June 2016

Tons of gold in rubbish dumps

At the moment there is more gold per kilogram in garbage and sewage sludge than in the ore from gold mines. This applies not only to gold, but also to silver, tungsten and other scarce metals. When will gold miners start mining the Dutch and Belgian rubbish dumps?

This is yet another example, which proves beyond any doubt that wealth is in fact a matter of properly arranging atoms. If all the atoms in garbage were to be processed into useful raw material, it would generate billions and make a large part of the mines obsolete.

Gold crystals from the wild. Source: Wikimedia Commons

Mines that now generate a lot of waste. For example, the extraction of the gold from one gold wedding ring causes around 20 tons of mining waste. Sodium cyanide, a deadly poisonous substance, and mercury, ditto, are currently used to extract gold. Rather than destroying our planet, let's create value from waste. Why eco coffee, and Forest Stewardship Council wood, but no Good Gold instead of the extremely bad gold of today?

Thanks to a scientific breakthrough at the University of Saskatchewan, Canada, there is now finally hope for a more environmentally and people-friendly extraction process for gold. When extracting gold from e-waste, residual waste from electronics such as smartphones, according to the three researchers led by Prof. Stephen Foley, 100 liters of low environmentally harmful and recyclable solvent are now used per kilogram of gold (of course they keep the composition of this solvent strictly secret), where up to now around 5000 liters of aqua regia have been used to soak the gold from the e-waste. Aqua regia is an extremely aggressive mixture of concentrated sulfuric and nitric acids.

Source
Golden Opportunity for U of S researchers, University of Saskatchewan, 2016

Video: Four new chemical elements are given names

Het is uitermate slecht voor je gezondheid is om een klontje moscovium of nihonium bij je in de buurt te hebben.

Dat valt namelijk uit elkaar in een fractie van een seconde, met een lawine aan ioniserende straling tot gevolg. Toch is de ontdekking en naamgeving van deze elementen groot nieuws. Nu kunnen we namelijk verder kijken.

De nieuwe elementen zijn:
Nihonium met symbool Nh, voor element 113,
Moscovium met symbool Mc, voor element 115,
Tennessine met symbool Ts, voor element 117 en
Oganesson met symbool Og, voor element 118.

Er bestaan hardnekkige vermoedens dat er een zogeheten Eiland van Stabiliteit bestaat. Dat zijn atoomkernen, die veel langer intact blijven dan je zou vermoeden op basis van hun grote massa. Sommige natuurkundigen denken zelfs dat er enkele van deze superzware atomen zich schuilhouden op aarde. Op dit moment is het zwaarste natuurlijke atoom dat ooit is aangetroffen, uranium-238. Dit is dan ook meteen de meest voorkomende uranium-isotoop en komt ongeveer net zoveel voor als tin. Maar misschien blijft het hier dus niet bij…

Japan heeft nu haar eigen element: nihonium. Ooit ununtrium geheten.

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