The unusual quadruple bonding of nitrogen in ThN.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 37996410.
- Also identified by DOI 10.1038/s41467-023-43208-z and PMC identifier 10667236.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Nitrogen has five valence electrons and can form a maximum of three shared electron-pair bonds to complete its octet, which suggests that its maximum bond order is three. With a joint anion photoelectron spectroscopy and quantum chemistry investigation, we report herein that nitrogen presents a quadruple bonding interaction with thorium in ThN. The quadruple Th≣N bond consists of two electron-sharing Th-N π bonds formed between the Th-6d<sub>xz</sub>/6d<sub>yz</sub> and N 2p<sub>x</sub>/2p<sub>y</sub> orbitals, one dative Th←N σ bond and one weak Th←N σ bonding interaction formed between Th-6d<sub>z</sub><sup>2</sup> and N 2s/2p<sub>z</sub> orbitals. The ThC molecule has also been investigated and proven to have a similar bonding pattern as ThN. Nonetheless, due to one singly occupied σ-bond, ThC is assigned a bond order of 3.5. Moreover, ThC has a longer bond length as well as a lower vibrational frequency in comparison with ThN.