This weird chemical bond acts like a mash-up of hydrogen and covalent bonds tells about hybrids of hydrogen and and covalent bonds. For short bond lengths these bonds become strong valence bonds and for long bond lengths weak hydrogen bonds which can even have length of 3 Angstrom.
Strange bonds entirely new to chemists predicted in ammonia hydrides tells that ammonium NH3 can form in the presence of hydrogen in very high pressure an exotic compound NH7, which can decay to NH4+ + H2+ H. NH4+ is also exotic.
Sticking together: Another look at chemical bonds and bonding discusses the theory of chemical bonds proposed by Prof. David Brown, which has turned out to be very successful. His article Another look at bonds and bonding is published in Structural Chemistry 31(1), 2019.
The bond theory of David Brown
The bond theory of David Brown is of special interest.
- The theory involves the notion of electric flux as a purely classical element. The delocalization of valence electrons is of course a non-classical element and one can argue that this aspect is not well-understood in standard chemistry.
In the TGD framework, the counterpart of electric flux is a flux tube carrying magnetic flux, which can be monopole flux. Thetube can also carry an electric flux and a simple modification of purely magneticflux tubes gives tubes carrying also an electric flux.
- The key concept besides the notions of valence defined as the number Nv of valence electrons belonging to bonds, and the number of valence bonds Nb, is valence strength defined as Nv/Nb. The total electric flux is the sum of fluxes assignable to the bonds and equals to the total electric charge -Nve of valence electrons.
By flux conservation, the electric fluxes at the ends of a given bond are opposite and this gives a strong constraint on the model. This condition is new from the point of standard bond theory and is purely classical.
- The configurations with minimum energy are expected to be symmetric. In this case, the electric fluxes for the bonds are expected to be identical and proportional to the common bond strength.
- An important implication of flux conservation in the symmetric case is that the valence strengths must be the same for bonded atoms. This condition excludes a large number of candidates.
- If Nb is larger than Nv the flux is fractional. This would represent an exotic situation. An interesting question, is whether the flux could correspond to a quark pair or two quark pairs possible in TGD framework in long scales: in this case the flux would be 1/3:rd or 2/3:rd of the flux associated with a single valence electron.
- The model works for many kinds of bonds, and is claimed to work even for hydrogen bonds, and can be used to predict possible bonding structures. What is remarkable, that the notion of conserved electric flux assignable to chemical bonds resonates with the TGD view that non-trivial space-time topology behind the notion of flux tube is directly visible at the level of chemistry.
TGD view about chemical bonds
I remember the time when I realized that TGD suggests a description of the chemical bond in terms of the space-time topology. Could chemistry books be wrong, was the question, which I barely dared to articulate.
Gradually I learned that chemistry books do not really allow any deeper understanding of chemical bonds. One just says that they follow from Schodinger equation but computational complexity prevents proving this.
TGD indeed implies a revolution in chemistry. Some chemical bonds are accompanied by flux tubes carrying dark particles with effective Planck constant heff>h=6h0. Valence electrons of the less electronegative atom would get to the flux tube and become dark. This leads to a model of valence bonds and the value of heff/h0= n increases as one moves to the right along the row of the periodic table. This implies delocalization of the valence electrons to longer scale scaling like heff2 for the Bohr model and this is essential for the delocalization. This delocalization would be essential for chemistry of valence bonds and for biochemistry in particular.
The article also mentions bonds without electrons. Hydrogen bond is of course an example of such: now it would be a proton that becomes dark and has heff>h. In water one could have a spectrum of heff values with various bond lengths and this would give water its very special properties. Even flux tubes without any particles but creating correlations and correlates of entanglement between atoms involved are possible.
Also heff<h bonds are possible. Randell Mills has found evidence for a variant of hydrogenfor which energies are scaled by factor 1/4: this would mean heff=h/2.
An interesting possibility is that in the past scaled down atoms with heff= h/2 have existed. Could they correspond to most of the dark matter, the primordial dark matter? The strange disappearance ofthe valence electrons of some transition metals in heating has been also known for decades: heating would provide the energy needed to increase he<>ff for valence electrons so that they become dark relative to us?
In biology metabolic energy would be used to increase heff, which serves as a kind of universal IQ as a measure of algebraic complexity.
For the topics discussed, see the article Revolution in chemistry.
For a summary of the earlier postings see Latest progress in TGD.