TY - JOUR
T1 - A synergistic approach to unraveling the thermodynamic stability of binary and ternary chevrel phase sulfides
AU - Lilova, Kristina
AU - Perryman, Joseph T.
AU - Singstock, Nicholas R.
AU - Abramchuk, Mykola
AU - Subramani, Tamilarasan
AU - Lam, Andy
AU - Yoo, Ray
AU - Ortiz-Rodríguez, Jessica C.
AU - Musgrave, Charles B.
AU - Navrotsky, Alexandra
AU - Velázquez, Jesús M.
N1 - Publisher Copyright:
Copyright © 2020 American Chemical Society.
PY - 2020/8/25
Y1 - 2020/8/25
N2 - State-of-the-art high temperature oxide melt solution calorimetry and density functional theory were employed to produce the first systematic study of thermodynamic stability in a series of binary and ternary Chevrel phases. Rapid microwave-assisted solid-state heating methods facilitated the nucleation of pure-phase polycrystalline MyMo6S8 (M = Fe, Ni, Cu; y = 0, 1, 2) Chevrel phases, and a stability trend was observed wherein intercalation of My species engenders stability that depends on both the electropositivity and ionic radii of the intercalant species. Ab initio calculations indicate that this stability trend results from competing ionic and covalent contributions, where transition metal intercalation stabilizes the Chevrel structure through increased ionicity but destabilizes the structure through reduced covalency of the Mo6S8 clusters. Our calculations predicted that over intercalation of high-valent My species leads to slight destabilization of the Mo6 octahedral cores, which we confirm using calorimetry and X-ray absorption spectroscopy. Our combined computational and calorimetric analysis reveals the interplay of the foundational principles of ionic and covalent bonding characteristics that govern the thermodynamic stability of Chevrel and other inorganic phases.
AB - State-of-the-art high temperature oxide melt solution calorimetry and density functional theory were employed to produce the first systematic study of thermodynamic stability in a series of binary and ternary Chevrel phases. Rapid microwave-assisted solid-state heating methods facilitated the nucleation of pure-phase polycrystalline MyMo6S8 (M = Fe, Ni, Cu; y = 0, 1, 2) Chevrel phases, and a stability trend was observed wherein intercalation of My species engenders stability that depends on both the electropositivity and ionic radii of the intercalant species. Ab initio calculations indicate that this stability trend results from competing ionic and covalent contributions, where transition metal intercalation stabilizes the Chevrel structure through increased ionicity but destabilizes the structure through reduced covalency of the Mo6S8 clusters. Our calculations predicted that over intercalation of high-valent My species leads to slight destabilization of the Mo6 octahedral cores, which we confirm using calorimetry and X-ray absorption spectroscopy. Our combined computational and calorimetric analysis reveals the interplay of the foundational principles of ionic and covalent bonding characteristics that govern the thermodynamic stability of Chevrel and other inorganic phases.
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U2 - 10.1021/acs.chemmater.0c02648
DO - 10.1021/acs.chemmater.0c02648
M3 - Article
AN - SCOPUS:85092036868
SN - 0897-4756
VL - 32
SP - 7044
EP - 7051
JO - Chemistry of Materials
JF - Chemistry of Materials
IS - 16
ER -