A first-principles study on new high-pressure metastable polymorphs of MoO{sub 2}

Journal Article · Sun May 15 00:00:00 EDT 2016 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/J.JSSC.2016.03.002· OSTI ID:22584096

Becker, Nils ^[1]; Dronskowski, Richard ^[1]

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1. Institut für Anorganische Chemie, RWTH Aachen University, Landoltweg 1, D-52056 Aachen (Germany)

The pressure-dependence of the stabilities of several MoO{sub 2} phases has been investigated by density-functional theory (GGA/PBE/PAW). Out of a set of 15 MX{sub 2} structures, the [SnO{sub 2}(II)], [α-PbO{sub 2}], and a modified rutile structure type were identified as possible metastable MoO{sub 2} polymorphs based on the analysis of thermodynamic properties and dynamic stability. High-pressure calculations suggest an orthorhombic TiO{sub 2} structure, dubbed [ortho-TiO{sub 2}], as a high-pressure polymorph at around 25 GPa. Furthermore, we find that the previously reported rutile-type MoO{sub 2} may be understood as a modified rutile type similar to the [VO{sub 2}] structure. - Graphical abstract: First-principles electronic structure and thermochemical calculations reveal four structure candidates as possible metastable polymorphs of MoO{sub 2}. Most promising is a distorted rutile-type similar to the known [VO{sub 2}] structure. An orthorhombic polymorph is proposed as a high-pressure polymorph. Display Omitted - Highlights: • Three possible metastable structure candidates for MoO{sub 2}. • Undistorted rutile type is improbable, a new distorted rutile-type MoO{sub 2} was suggested. • Orthorhombic phase of MoO{sub 2} (ortho-TiO{sub 2} type) should form at 25 GPa. • ab initio thermochemical data provided for MoO{sub 2}.

• OSTI ID: 22584096
• Journal Information: Journal of Solid State Chemistry, Vol. 237; Other Information: Copyright (c) 2016 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0022-4596
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
DENSITY FUNCTIONAL METHOD
ELECTRONIC STRUCTURE
LEAD OXIDES
MOLYBDENUM OXIDES
ORTHORHOMBIC LATTICES
PHONONS
PRESSURE DEPENDENCE
PRESSURE RANGE GIGA PA
PRESSURE RANGE MEGA PA 10-100
RUTILE
STABILITY
THERMODYNAMIC PROPERTIES
TIN OXIDES
TITANIUM OXIDES
VANADIUM OXIDES