Expanding the library of known inorganic materials with functional electronic or magnetic behavior is a longstanding goal in condensed matter physics and materials science. Recently, the transition metal chalchogenides including selenium and sulfur have been of interest because of their correlated-electron properties, as seen in the iron based superconductors and the transition metal dichalcogenides. However, the chalcogenide chemical space is less explored than that of oxides, and there is an open question of whether there may be new materials heretofore undiscovered.We perform a systematic combined theoretical and experimental search over ternary phase diagrams that are empty in the Inorganic Crystal Structure Database containing cations, transition metals, and one of selenium or sulfur. In these 27 ternary systems, we use a probabilistic model to reduce the likelihood of false negative predictions, which results in a list of 24 candidate materials.We then conduct a variety of synthesis experiments to check the candidate materials for stability.While the prediction method did obtain previously unknown compositions that are predicted stable within density functional theory, none of the candidate materials formed in our experiments. We come to the conclusion that these phase diagrams are "empty" in the case of bulk synthesis, but it remains a possibility that alternate synthesis routes may produce some of these phases.

We report the magnetic phase diagram of Mn1−xFexPSe3 which represents a random magnet system of two antiferromagnetic systems with mixed spin, mixed spin anisotropies, mixed nearest neighbor magnetic interactions and mixed periodicities in their respective antiferromagnetic structure. Bulk samples of Mn1−xFexPSe3 have been prepared and characterized phase pure by powder X-ray and neutron diffraction and X-ray fluorescence. Nature and extent of magnetically ordered state has been established using powder neutron diffraction, dc magnetic susceptibility and heat capacity. Long-range magnetic ordering exists between x = 0.0 and 0.25 (MnPSe3-type) and between x = 0.875 and 1 (FePSe3-type). A short-range magnetic order with existence of both MnPSe3-and FePSe3-type nano-clusters has been established between x = 0.25 and 0.875. Irreversibility in dc magnetization measurements, also characterized by isothermal and thermoremanent magnetization measurements suggest similarities to magnetic nanoparticles where uncompensated surface spins result in a non-zero TRM and IRM response, further reinforcing existence of magnetic nano-clusters or domains. A spin glass state, observed in analogous Mn1−xFexPS3, has been ruled out and formation of nano-clusters exhibiting both ordering types results from unusually high anisotropy values. The effect of ligand contributions to the spin-orbit interactions has been suggested as a possible explanation for high D values in these compounds.

We report the first detailed investigation of K2MnS2 and K2MnSe2 from the K2MnS2 structure type and their magnetic solid solution K2MnS2−xSex and find that compounds of this structure type consist of strongly-coupled pseudo-one-dimensional antiferromagnetic chains that collectively represent a frustrated two-dimensional triangular antiferromagnet. Bulk samples of K2MnS2−xSex with 0 ≤ x ≤ 2 are characterized using X-ray diffraction, neutron diffraction, magnetization and heat capacity measurements. An incommensurate cycloid magnetic structure with a magnetic propagation vector k = [0.58 0 1] is observed for all samples in K2MnS2−xSex, and the ordering is robust despite a 12% increase in cell volume. Geometric frustration of chains results in incommensurability along a and a two-step magnetic transition. The varying geometries accessible in compounds of this structure type are presented as promising avenues to tune frustration.

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Rapid materials discovery in inorganic chemistry should combine predictive computational tools with fast experimental syntheses. We apply such a tandem approach to explore the Ba−Ru−S phase space, where no ternary compounds are yet known to exist. Related ternary oxide ruthenates and ternary iron sulfides exhibit interesting electronic properties due to d-electron correlations, such as superconductivity, metamagnetism, and quantum phase transitions. We use a combination of evolutionary algorithms and density functional theory to inform traditional and in situ diffraction methods. In the course of our investigation, we find that convex hull constructions of the binary constituents inform interpretation of the ternary hull, which in this case has two compounds near thermodynamic stability. Our experimental study does not reveal formation of the candidates BaRu 2 S 2 or BaRuS 3 , but it does provide the structure of a high-temperature polymorph of BaS 2 . This methodology can be exploited to study other ternary systems to screen for novel phases.