Uncovering the Thermo-Kinetic Origins of Phase Ordering in Mixed-Valence Antimony Tetroxide by First-Principles Modeling.

Title Uncovering the Thermo-Kinetic Origins of Phase Ordering in Mixed-Valence Antimony Tetroxide by First-Principles Modeling.
Authors C.E. Kim; S.H. Yoo; D.F. Bahr; C. Stampfl; A. Soon
Journal Inorg Chem
DOI 10.1021/acs.inorgchem.7b00661
Abstract

Phase ordering in the mixed-valence oxide Sb2O4 has been examined by density functional theory (DFT) calculations. We find that the ground-state total energies of the two phases (? and ?) are almost degenerate and are highly sensitive to the choice of the approximation to the exchange correlation (xc) functional used in our calculations. Interestingly, with the inclusion of the zero-point energy corrections, the ? phase is predicted to be the ground state polymorph for most xc functionals used. We also illustrate the pronounced stereochemical activity of Sb in these polymorphs of Sb2O4, setting an exception to the Keve and Skapski rule. Here, we find that the actual bonding in the ? phase is more asymmetric, while the anomalous stability of the ? phase could be rationalized from kinetic considerations. We find a non-negligible activation barrier for this ?-? phase transition, and the presence of a saddle point (? phase) supports the separation of Sb(III) over a continuous phase transition, as observed in experiments.

Citation C.E. Kim; S.H. Yoo; D.F. Bahr; C. Stampfl; A. Soon.Uncovering the Thermo-Kinetic Origins of Phase Ordering in Mixed-Valence Antimony Tetroxide by First-Principles Modeling.. Inorg Chem. 2017;56(11):65456550. doi:10.1021/acs.inorgchem.7b00661

Related Elements

Antimony

See more Antimony products. Antimony (atomic symbol: Sb, atomic number: 51) is a Block P, Group 15, Period 5 element with an atomic radius of 121.760. Antimony Bohr Model The number of electrons in each of antimony's shells is 2, 8, 18, 18, 5 and its electron configuration is [Kr] 4d10 5s2 5p3. The antimony atom has a radius of 140 pm and a Van der Waals radius of 206 pm. Antimony was discovered around 3000 BC and first isolated by Vannoccio Biringuccio in 1540 AD. In its elemental form, antimony has a silvery lustrous gray appearance. Elemental Antimony The most common source of antimony is the sulfide mineral known as stibnite (Sb2S3), although it sometimes occurs natively as well. Antimony has numerous applications, most commonly in flame-retardant materials. It also increases the hardness and strength of lead when combined in an alloy and is frequently employed as a dopant in semiconductor materials. Its name is derived from the Greek words anti and monos, meaning a metal not found by itself.

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