May 6th, 2018
The site fairsharing.org is a repository of information about FAIR (Findable, Accessible, Interoperable and Reusable) objects such as research data.
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Tags: above site, chemical components, Findability, Human behavior, Information, Information architecture, Information science, Institutional repository, journal data editor, Knowledge, Knowledge representation, Open access, Open access in Australia, Oscar, PDF, recognition software, Technology/Internet, Web design
Posted in Interesting chemistry | 2 Comments »
April 18th, 2018
The molecules below were discussed in the previous post as examples of highly polar but formally neutral molecules, a property induced by aromatisation of up to three rings. Since e.g. compound 3 is known only in its protonated phenolic form, here I take a look at the basicity of the oxygen in these systems to see if deprotonation of the ionic phenol form to the neutral polar form is viable.
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Tags: Antiseptics, Aromatization, Chemistry, energy, energy minimum, Hydrogen, Molecule, Neurotoxins, Science
Posted in Interesting chemistry | No Comments »
April 13th, 2018
In several posts a year or so ago I considered various suggestions for the most polar neutral molecules, as measured by the dipole moment. A record had been claimed[cite]10.1002/anie.201508249[/cite] for a synthesized molecule of ~14.1±0.7D. I pushed this to a calculated 21.7D for an admittedly hypothetical and unsynthesized molecule. Here I propose a new family of compounds which have the potential to extend the dipole moment for a formally neutral molecule up still further.
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Tags: aromatisation stabilization energy, Chemical polarity, chemical properties, Chemistry, Dipole, Electric dipole moment, Electromagnetism, energy, Moment, Nature, Physical quantities, Physics, Potential theory
Posted in Interesting chemistry | 11 Comments »
March 18th, 2018
Around the time of the 2012 olympic games, the main site for which was Stratford in east London, I heard a fascinating talk about the “remediation” of the site from the pollution caused by its industrial chemical heritage. Here I visit another, arguably much more famous and indeed older industrial site.
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Tags: City: London, Environment, Environmental Issues, Environmental toxicology, Geography of London, industrial chemical heritage, industrial site, London Borough of Newham, London boroughs, Pollution, Province/State: Swansea, Queen Elizabeth Olympic Park, river Tawe, Stratford, Stratford London, Stratford station, Summer Olympics, the 2012 olympic games, unfortunate by-product, William Blake
Posted in Interesting chemistry | No Comments »
March 18th, 2018
I have posted often on the chemical phenomenon known as hypervalency, being careful to state that as defined it applies just to “octet excess” in main group elements. But what about the next valence shell, occurring in transition metals and known as the “18-electron rule”? You rarely hear the term hypervalency being applied to such molecules, defined presumably by the 18-electron valence shell count being exceeded. So the following molecule (drawn in three possible valence bond representations) first made in 1992 intrigues.[cite]10.1002/anie.199203231[/cite]
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Posted in Hypervalency | 3 Comments »
March 7th, 2018
C&EN has again run a vote for the 2017 Molecules of the year. Here I take a look not just at these molecules, but at how FAIR (Findable, Accessible, Interoperable and Reusable) the data associated with these molecules actually is.
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Tags: Carotenoids, Chemistry, Epoxides, Macrocycles, Organic chemistry, Organofluorides, PDF, Peptides, search engine, search program, search.datacite.org search engine, Technology/Internet
Posted in Chemical IT, crystal_structure_mining, Interesting chemistry | No Comments »
March 4th, 2018
A bond index (BI) approximately measures the totals of the bond orders at any given atom in a molecule. Here I ponder what the maximum values might be for elements with filled valence shells.
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Tags: Atom, Chemical bond, chemical bonding, chemical properties, Chemistry, metal bond indices, Molecule, Nature, Quantum chemistry, Residential REITs, Resonance, Tennessine, Valence, Valence electron
Posted in Interesting chemistry | No Comments »
February 24th, 2018
Another post inspired by a comment on an earlier one; I had been discussing compounds of the type I.In (n=4,6) as possible candidates for hypervalency. The comment suggests the below as a similar analogue, deriving from observations made in 1989.[cite]10.1016/S0040-4039(00)99132-9[/cite]
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Tags: C, chemical bonding, Chemistry, free energy, Hypervalent molecule, Matter, Molecular geometry, Nature, Nitrogen
Posted in Hypervalency | 3 Comments »
February 23rd, 2018
A little while ago I pondered allotropic bromine, or Br(Br)3. But this is a far wackier report[cite]10.1126/science.aao7293[/cite] of a molecule of light.
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Tags: Atomic physics, Bromine, Bromine compounds, chemist, Chemistry, Halogens, Hypobromite, Oxidizing agents
Posted in Interesting chemistry | No Comments »
February 16th, 2018
Last year, this article[cite]10.1038/nchem.2716[/cite] attracted a lot of attention as the first example of molecular helium in the form of Na2He. In fact, the helium in this species has a calculated‡ bond index of only 0.15 and it is better classified as a sodium electride with the ionisation induced by pressure and the presence of helium atoms. The helium is neither valent, nor indeed hypervalent (the meanings are in fact equivalent for this element). In a separate blog posted in 2013, I noted a cobalt carbonyl complex containing a hexacoordinate hydrogen in the form of hydride, H–. A comment appended to this blog insightfully asked about the isoelectronic complex containing He instead of H–. Here, rather belatedly, I respond to this comment!
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Tags: chemical bonding, Chemical elements, chemical shift, Chemistry, helium, Hydride, Hydrogen, Hypervalent molecule, Matter, Metal hydrides, Reducing agents, Transition metal hydride
Posted in Hypervalency | 4 Comments »