ε-TiO, a Novel Stable Polymorph of Titanium Monoxide

Shinsaku Amano, Dimitri Bogdanovski, Hisanori Yamane, Masami Terauchi, Richard Dronskowski

    Research output: Contribution to journalArticlepeer-review

    34 Citations (Scopus)

    Abstract

    For the Ti/O system, three titanium monoxide (TiO) phases (α, β, and γ) with defective NaCl-type structures and a high-temperature hexagonal phase (H) have been known for decades. In this work, single crystals of a novel polymorph, ε-TiO, were synthesized by using a bismuth flux. X-ray diffraction (XRD) revealed a hexagonal crystal structure (a=4.9936(3) Å, c=2.8773(2) Å, P6? 2m) that is isotypic with ε-TaN. While the Ti atoms are surrounded by trigonal prismatic (sixfold coordination) and trigonal planar (threefold coordination) arrangements of O atoms, the O atoms are found in a pseudo-square-pyramidal arrangement of Ti atoms. First-principles calculations of the formation enthalpy and the electron and phonon density of states and crystal orbital Hamilton population (COHP) analysis revealed that ε-TiO is more stable than α-TiO, which had previously been regarded as the most stable phase at low temperatures.

    Original languageEnglish
    Pages (from-to)1652-1657
    Number of pages6
    JournalAngewandte Chemie - International Edition
    Volume55
    Issue number5
    DOIs
    Publication statusPublished - 2016 Jan 26

    Keywords

    • chemical bonding
    • computational chemistry
    • phase stability
    • polymorphism
    • titanium monoxide

    ASJC Scopus subject areas

    • Chemistry(all)
    • Catalysis

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