Alkalides are anionic alkali compounds containing e.g. sodide (Na – ), kalide (K – ), rubidide (Rb – ) or caeside (Cs – ). Around 90 examples can be found in the Cambridge structure database (see DOI: 10.14469/hpc/3453 for the search query and results). So what about the ammonium analogue, ammonide (NH 4 – )? A quick search of Scifinder drew a blank!
An article with the title shown above in part recently appeared. Given the apparent similarity of HF1- to CH3F1- and CH3F2-, the latter of which I introduced on this blog previously, I thought it of interest to apply my analysis to HF1-.
FAIR data is increasingly accepted as a description of what research data should aspire to; Findable, Accessible, Inter-operable and Re-usable, with Context added by rich metadata (and also that it should be Open). But there are two sides to data, one of which is the raw data emerging from say an instrument or software simulations […]
For around 16 years, Floyd Romesberg’s group has been exploring un-natural alternatives (UBPs) to the Watson-Crick base pairs (C-G and A-T) that form part of the genetic code in DNA.
I started this story by looking at octet expansion and hypervalence in non-polar hypercoordinate species such as S(-CH3)6, then moved on to S(=CH2)3. Finally now its the turn of S(≡CH)2.‡
Previously: “Non-polar” species such as SeMe 6 , SMe 6 , ClMe 3 , ClMe 5 all revealed interesting properties for the Se-C, S-C or Cl-C “single” bonds. The latter two examples in particular hinted at internal structures for these single bonds, as manifested by two ELF basins for some of the bonds.
Following on from discussing octet expansion in species such as SeMe6, ClMe3 and ClMe5, I felt impelled to return to SF6, often used as an icon for hypervalence.
PIDapalooza is a new forum concerned with discussing all things persistent, hence PID. You might wonder what possible interest a chemist might have in such an apparently arcane subject, but think of it in terms of how to find the proverbial needle in a haystack in a time when needles might look all very similar.
A few years back, I took a look at the valence-shell electron pair repulsion approach to the geometry of chlorine trifluoride, ClF3 using so-called ELF basins to locate centroids for both the covalent F-Cl bond electrons and the chlorine lone-pair electrons.
One thread that runs through this blog is that of hypervalency . It was therefore nice to come across a recent review of the concept[1] which revisits the topic, and where a helpful summary is given of the evolving meanings over time of the term hypervalent.
An N-B single bond is iso-electronic to a C-C single bond, as per below. So here is a simple question: what form does the distribution of the lengths of these two bonds take, as obtained from crystal structures?