In the paragraph following eq 28, the average bond valence was incorrectly referred to as V/R. It has been corrected to V/N. The paper originally posted to the web on September 3, 2009, and was reposted on September 24, 2009.

http://pubs.acs.org/doi/pdf/10.1021/cr900053k

Recent developments in the methods and applications of the bond valence model.

Predicting the stability of the perovskite structure remains a long-standing challenge for the discovery of new functional materials for many applications including photovoltaics and electrocatalysts. We developed an accurate, physically interpretable, and one-dimensional tolerance factor, τ, that correctly predicts 92% of compounds as perovskite or nonperovskite for an experimental dataset of 576 ABX 3 materials ( X = O 2− , F − , Cl − , Br − , I − ) using a novel data analytics approach based on SISSO (sure independence screening and sparsifying operator). τ is shown to generalize outside the training set for 1034 experimentally realized single and double perovskites (91% accuracy) and is applied to identify 23,314 new double perovskites ( A 2 BB′X 6 ) ranked by their probability of being stable as perovskite. This work guides experimentalists and theorists toward which perovskites are most likely to be successfully synthesized and demonstrates an approach to descriptor identification that can be extended to arbitrary applications beyond perovskite stability predictions.

/pdf/new-tolerance-factor-to-predict-the-stability-of-perovskite-3gb1sn7v7l.pdf

New tolerance factor to predict the stability of perovskite oxides and halides

The existence of new compounds is often postulated by solid state chemists by replacing an ion in the crystal structure of a known compound by a chemically similar ion. In this work, we present how this new compound discovery process through ionic substitutions can be formulated in a mathematical framework. We propose a probabilistic model assessing the likelihood for ionic species to substitute for each other while retaining the crystal structure. This model is trained on an experimental database of crystal structures, and can be used to quantitatively suggest novel compounds and their structures. The predictive power of the model is demonstrated using cross-validation on quaternary ionic compounds. The different substitution rules embedded in the model are analyzed and compared to some of the traditional rules used by solid state chemists to propose new compounds (e.g., ionic size).

http://web.mit.edu/ceder/publications/Hautier_Ceder_ionic_substitutions.pdf

Data Mined Ionic Substitutions for the Discovery of New Compounds

Predicting the stability of the perovskite structure remains a longstanding challenge for the discovery of new functional materials for many applications including photovoltaics and electrocatalysts. We developed an accurate, physically interpretable, and one-dimensional tolerance factor, {\tau}, that correctly predicts 92% of compounds as perovskite or nonperovskite for an experimental dataset of 576 $ABX_3$ materials ($\textit{X} =$ $O^{2-}$, $F^-$, $Cl^-$, $Br^-$, $I^-$) using a novel data analytics approach based on SISSO (sure independence screening and sparsifying operator). {\tau} is shown to generalize outside the training set for 1,034 experimentally realized single and double perovskites (91% accuracy) and is applied to identify 23,314 new double perovskites ($A_2$$\textit{BB'}$$X_6$) ranked by their probability of being stable as perovskite. This work guides experimentalists and theorists towards which perovskites are most likely to be successfully synthesized and demonstrates an approach to descriptor identification that can be extended to arbitrary applications beyond perovskite stability predictions.

New Tolerance Factor to Predict the Stability of Perovskite Oxides and Halides

ABO3 perovskites are oxide materials that are used for a variety of applications such as solid oxide fuel cells, piezo-, ferro-electricity and water splitting. Due to their remarkable stability with respect to cation substitution, new compounds for such applications potentially await discovery. In this work, we present an exhaustive dataset of formation energies of 5,329 cubic and distorted perovskites that were calculated using first-principles density functional theory. In addition to formation energies, several additional properties such as oxidation states, band gap, oxygen vacancy formation energy, and thermodynamic stability with respect to all phases in the Open Quantum Materials Database are also made publicly available. This large dataset for this ubiquitous crystal structure type contains 395 perovskites that are predicted to be thermodynamically stable, of which many have not yet been experimentally reported, and therefore represent theoretical predictions. The dataset thus opens avenues for future use, including materials discovery in many research-active areas.

/pdf/high-throughput-dft-calculations-of-formation-energy-x3s1y04ge5.pdf

High-throughput DFT calculations of formation energy, stability and oxygen vacancy formation energy of ABO 3 perovskites.

On the basis of the bond-valence model (BVM) and structure-map technology, the structural stability and formability of ABO(3)-type perovskite compounds were investigated in 376 ABO(3)-type compounds. A new criterion of structural stability for ABO(3)-type perovskite compounds has been established by the bond-valence calculated tolerance factors, which are in the range 0.822-1.139. All global instability indices for ABO(3)-type perovskite compounds are found to be less than 1.2 v.u. (valence units) and increase with a decrease in oxidation state of the B cations (i.e. structural stability in the formation of an ideal cubic perovskite follows the order A(+)B(5+)O(3)-type > A(2+)B(4+)O(3)-type > A(3+)B(3+)O(3)-type). Three new two-dimensional structure maps were constructed based on the ideal A-O and B-O bond distances derived from the BVM. These maps indicate the likelihood of particular perovskite compounds being formed. The present work enables novel perovskite and perovskite-related compounds to be explored by screening all the possible elemental combinations in future crystal engineering.

/pdf/structural-stability-and-formability-of-abo3-type-perovskite-3m86vxok8t.pdf

Structural stability and formability of ABO3-type perovskite compounds.

Previous studies have displayed various conclusions about the effect of preparation factors on the photoreduction property of ZnIn2S4. Therefore, it is not easy to figure out the optimal preparation conditions of ZnIn2S4 for Cr(VI) photoreduction. To ensure Cr(VI) reduction efficiency, various ZnIn2S4 photocatalysts were prepared in different solvents (i.e., water and ethylene glycol) and temperatures (i.e., 120 °C, 150 °C and 180°C). Different characterization methods were used to explain the difference in optical performance and photocatalytic property among the obtained samples. The results show that all the samples exhibit a similar band gap. The reaction solvent and temperature have a great influence on the surface morphology and optical property, leading to the different photocatalytic properties. ZnIn2S4 synthesized at 120 °C in the solvothermal condition shows the optimal efficiency on Cr(VI) photoreduction due to the effective utilization of photo-induced carriers. The reasonable analysis and effective conclusion presented may provide the optimal synthesis method of ZnIn2S4 to effectively remove Cr(VI) from water environment.

/pdf/study-on-optimum-preparation-conditions-of-znin2s4-to-1cyqc72k.pdf

Huan Zhang

Papers

Structural stability and formability of ABO3-type perovskite compounds.

Study on Optimum Preparation Conditions of ZnIn2S4 to Effectively Reduce Cr(VI) under Visible Light Radiation