Hydride ions in oxide hosts hidden by hydroxide ions.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 24662678.
- Also identified by DOI 10.1038/ncomms4515 and PMC identifier 3973043.
- Licence recorded as CC BY-NC-ND.
- Because redistribution is not established, this page shows the abstract only. Follow the links below for the full text.
Abstract
The true oxidation state of formally 'H(-)' ions incorporated in an oxide host is frequently discussed in connection with chemical shifts of (1)H nuclear magnetic resonance spectroscopy, as they can exhibit values typically attributed to H(+). Here we systematically investigate the link between geometrical structure and chemical shift of H(-) ions in an oxide host, mayenite, with a combination of experimental and ab initio approaches, in an attempt to resolve this issue. We demonstrate that the electron density near the hydrogen nucleus in an OH(-) ion (formally H(+) state) exceeds that in an H(-) ion. This behaviour is the opposite to that expected from formal valences. We deduce a relationship between the chemical shift of H(-) and the distance from the H(-) ion to the coordinating electropositive cation. This relationship is pivotal for resolving H(-) species that are masked by various states of H(+) ions.