Structures and Phase Transitions in (MoO2)2P2O7

Lister, S.E.; Soleilhavoup, A.; Withers, R.L.; Hodgkinson, P.; Evans, J.S.O.

Abstract

We report structural investigations into (MoO2)2P2O7 using a combination of X-ray, neutron and electron diffraction, and solid-state NMR supported by first principles quantum chemical calculations. These reveal a series of phase transitions on cooling at temperatures of 377 and 325 K. The high temperature γ-phase has connectivity consistent with that proposed by Kierkegaard at room temperature (but with improved bond length distribution), and contains 13 unique atoms in space group Pnma with lattice parameters a = 12.6577(1) Å, b = 6.3095(1) Å, c = 10.4161(1) Å, and volume 831.87(1) Å3 from synchrotron data at 423 K. The low temperature α-structure was indexed from electron diffraction data and contains 60 unique atoms in space group P21/c with cell parameters a = 17.8161(3) Å, b = 10.3672(1) Å, c = 17.8089(3) Å, β = 90.2009(2)°, and volume 3289.34(7) Å3 at 250 K. First principles calculations of 31P chemical shift and J couplings were used to establish correlation between local structure and observed NMR parameters, and 1D and 2D 31P solid-state NMR used to validate the proposed crystal structures. The intermediate β-phase is believed to adopt an incommensurately modulated structure; 31P NMR suggests a smooth structural evolution in this region.

Citation

Lister, S., Soleilhavoup, A., Withers, R., Hodgkinson, P., & Evans, J. (2010). Structures and Phase Transitions in (MoO2)2P2O7. Inorganic Chemistry, 49(5), 2290-2301. https://doi.org/10.1021/ic902166j

• Journal Article Type: Article
• Publication Date: 2010-03
• Deposit Date: Feb 1, 2012
• Journal: Inorganic Chemistry
• Print ISSN: 0020-1669
• Electronic ISSN: 1520-510X
• Publisher: American Chemical Society
• Peer Reviewed: Peer Reviewed
• Volume: 49
• Issue: 5
• Pages: 2290-2301
• DOI: https://doi.org/10.1021/ic902166j
• Public URL: https://durham-repository.worktribe.com/output/1508604