K0.72Fe0.72Ti1.28O4, a layered mixed-metal oxide belonging to the lepidocrocite structure type, was grown out of a molten KCl-KF mixture at 800 degrees C. The compound crystallizes in orthorhombic space group Cmcm and exhibits two-dimensional layers, composed of mixed Fe/Ti octahedra, separated by K ions that occupy the interlayer layer space and maintain charge balance. The targeted flux synthesis of the Ni, Cu, and Zn analogs was carried out after density functional theory (DFT) calculations predicted their formation to be energetically favorable, yielding K0.77Ni0.38Ti1.62O4, K0.77Cu0.38Ti1.62O4, and K0.73Zn0.36Ti1.64O4. All four compositions can be prepared via con-ventional solid-state technique by mixing and heating stoichiometric amounts of KNO3, appropriate transition metal oxide precursors, and TiO2.

A new mayenite-type strontium oxy-chloride, Sr(12)Al(3.44)Fe(8.1)6Ge(2.38)O(32)Cl(4.34), was grown from a SrCl2 flux at 1000 degrees C. The compound crystallizes in the complex three-dimensional chloromayenite structure type, a rare calcium aluminum oxide mineral of cubic symmetry, exhibiting nanocages that contain Sr and Cl ions. The lattice framework is composed of corner-sharing, three-component Al/Fe/Ge site-mixed tetrahedra. The compound crystallizes in the cubic space group I-43d with lattice parameter a = 12.6126(3) angstrom.

Single crystals of two new rubidium ferrites, RbFeSiO4 and RbFeGeO4, were grown out of a eutectic RbCl-RbF melt. Both compounds crystallize in the noncentrosymmetric orthorhombic space group Ima2 and exhibit a three-dimensional porous framework structure composed of statistically disordered (Fe/T)O-4 (T = Si, Ge) tetrahedra that corner-share to generate large channels running down the c-axis. These channels are occupied by Rb ions to maintain charge balance. RbFeSiO4 can also be prepared via a solid-state reaction by mixing and heating stoichiometric amounts of Rb2CO3, Fe2O3 and elemental Si; however, a similar approach for preparing RbFeGeO4 yielded a mixture of RbFeGeO4 and RbFeGe2O6. Powder second harmonic generation (SHG) measurements of RbFeSiO4 determined that the material is SHG-active with an intensity of 0.5 times of alpha-SiO2. First principles calculations in the form of density-functional theory indicated that it would be possible to ion exchange the Rb cation for other alkali metal cations. Applying a molten alkali nitrate salt-bath treatment at low soak temperatures of 350 degrees C-450 degrees C and short soak times of similar to 16 h resulted in the almost complete replacement of rubidium with potassium and the partial replacement of rubidium with cesium, yielding K0.92Rb0.08FeSiO4, K-0.91 Rb0.09FeGeO4, and Cs0.48Rb0.52FeGeO4. No ion-exchange was observed when RbFeSiO4 was soaked in molten CsNO3; however, it was possible to force the exchange by using a CsCl melt at 680 degrees C to yield Cs0.13RB0.87FeSiO4.

A new mayenite-type strontium oxy-chloride, Sr12Al3.44Fe8.16Ge2.38O32Cl4.34, was grown from a SrCl2 flux at 1000 °C. The compound crystallizes in the complex three-dimensional chloromayenite structure type, a rare calcium aluminum oxide mineral of cubic symmetry, exhibiting nanocages that contain Sr and Cl ions. The lattice framework is composed of corner-sharing, three-component Al/Fe/Ge site-mixed tetrahedra. The compound crystallizes in the cubic space group I-43d with lattice parameter a = 12.6126 Å.

We demonstrate a fast solution phase ligand exchange process to generate AgBiS2 nanocrystal inks using a cinnamic acid derivative as an additive to accelerate the phase transfer to polar solvents. Photoconductivity in thin films assembled from the AgBiS2 nanocrystal inks is achieved by using a single deposition step, avoiding multiple layer iterations. The inks remain colloidally stable after several days, and photoconductor devices showcase fast response times <4 ms, high on/off ratios similar to 20, and film conductivities of similar to 3 x 10(-8) S/cm, highlighting the promise in completely solution processed thin film electronics and optoelectronics using eco-friendly materials.

Single crystals of new cesium cobalt silicates and germanates exhibiting three-dimensional, ion-exchangeable crystal structures were grown from a mixed CsCl–CsF flux, and their electronic and magnetic properties were studied using DFT calculations.

Deep blue, prism-shaped, X-ray diffraction quality single crystals of a new quaternary rubidium cobalt germanate, exact composition Rb2Co1.85Ge1.15O6, were grown by soaking a pre-reacted polycrystalline powder in a molten RbCl/RbF eutectic flux (melting point = 546 °C) at 700 °C in a silver reaction vessel. The complex was characterized by single crystal X-ray diffraction and its elemental composition was semi-quantitatively confirmed by energy dispersive spectroscopy (EDS). Rb2Co1.85Ge1.15O6 crystallizes in the noncentrosymmetric orthorhombic space group C2221 with lattice parameters a = 6.5971(2) Å, b = 9.8791(3) Å and c = 10.8819(3) Å in the K2ZnSi2O6 structure type. The crystal structure consists of a three-dimensional network, composed of Co and mixed Co/Ge tetrahedra, and features cavities occupied by Rb cations. X-ray diffraction quality single crystals of a novel rubidium cobalt germanate, Rb2Co1.85Ge1.15O6, were grown by soaking a pre-reacted powder, targeted for preparing Rb4.51Co2.35Ge5.10O15F1.96, in a RbCl-RbF eutectic melt at 700 °C. The complex was characterized by single crystal X-ray diffraction and found to crystallize in the orthorhombic space group C2221 in the K2ZnSi2O6 structure type.

Single crystals of Rb0.74Ga6.62Ti0.38O11 (RGTO) were grown from a mixed RbCl-RbF flux at 850 degrees C. The compound crystallizes in the RbGa7O11 structure type, which is reminiscent of the hollandite and beta-Ga2O3 structure types. RGTO crystallizes in the monoclinic space group P2/m with lattice parameters a = 8.3355 (8) angstrom, b = 3.0286 (3) angstrom, c = 9.5028 (9) angstrom, and beta = 114.620 (3)degrees. The crystal structure of RGTO is comprised of GaO6 and mixed (Ga/Ti)O-6 octahedra and GaO4 tetrahedra connected in a complex three-dimensional, anionic framework exhibiting eight-sided channels that are occupied by disordered Rb cations required for charge balance. First principles calculations in the form of density functional theory were performed, which indicated the complex to be a charge transfer semiconductor.

RbMgF3, a perovskite halide, serendipitously crystallized from a reaction between MgCl2 and TiO2 in molten RbCl/RbF eutectic flux (melting point = 546 °C) and was characterized by single crystal X-ray diffraction. RbMgF3 crystals can also be grown directly in higher yield using a molten RbCl–RbF flux layered over MgCl2 or MgF2 contained in a silver tube at 575 °C. RbMgF3 crystallizes in the hexagonal space group P63/mmc in the 6H hexagonal perovskite structure type with lattice parameters a = 5.8368(2) Å and c = 14.2087(5) Å. The crystal structure exhibits face-sharing Mg2F9 octahedra connected via corner-sharing MgF6 octahedra. Elemental composition for RbMgF3 was semi-quantitatively confirmed by energy dispersive spectroscopy (EDS). X-ray diffraction quality single crystals of RbMgF3 were grown from a molten RbCl/RbFeutectic flux at 850 °C and used for structure determination using single crystal X-raydiffraction. The compound crystallizes in the hexagonal space group P63/mmc in the 6Hhexagonal structure type.

Single crystal growth of new germanate salt inclusion materials. [(Rb6F)(Rb4F)][Ge14O32] exhibits room temperature luminescence and [(Rb6F)(Rb3.1Co0.9F0.96)][Co3.8Ge10.2O30F2] demonstrates Co/Ge mixing and an unanticipated Rb/Co inclusion.

Two polymorphs of a new cesium ferrogermanate zeotype, CsFeGeO4, were synthesized using the molten CsCl-CsF flux growth approach at 900 °C. The orthorhombic polymorph, referred to as (1), crystallizes in the centrosymmetric nonpolar Pbcm space group. The compound exhibits a three-dimensional porous framework structure composed of disordered (Fe/Ge)O4 corner-sharing tetrahedra that generate large eight-sided channels running down the b-axis. These channels are occupied by Cs ions that provide charge balance to the anionic framework. Minor modifications in the reaction conditions lead to the synthesis of a monoclinic polymorph of CsFeGeO4, referred to as (2), crystallizing in the noncentrosymmetric polar space group P21 and exhibiting an identical framework structure to (1), albeit featuring ordered FeO4 and GeO4 tetrahedra. Solid state synthesis of CsFeGeO4 produces a polycrystalline mixture of (1) and (2), referred to as (6). Polarization-electric field (P-E) measurements of (6) indicate that the material is not ferroelectric. Powder second harmonic generation (SHG) measurements of (2) and (6) revealed them to be SHG active with intensities of 1.5 and 0.2 times that of α-SiO2, respectively. The temperature dependent magnetic susceptibility of (2) exhibits a downturn at T = 2.6 K, indicative of antiferromagnetic ordering. First-principles calculations in the form of density functional theory showed that (1) and (2) differ in stability by only 1.3 meV/atom, with (2) being the thermodynamically stabilized phase. Additional calculations for (1), using molten nitrate as reference, predicted the formation of energetically favorable phases, KFeGeO4 (3) and RbFeGeO4 (4). They were subsequently prepared via a molten nitrate salt bath treatment of (1) to replace Cs with K and Rb, affording (3) and (4) as single-crystal to single-crystal ion exchange products. Structure determination and property measurements for a pyroxene phase, CsFeGe2O6, referred to as (5), are also reported. This compound crystallized as a side product in the flux synthesis of CsFeGeO4.

A family of rubidium-containing mixed-metal titanates, RbxMyTi8-yO16 (M = Mg, Mn, Fe, Ni, and Cu) was prepared as high-quality single crystals employing a molten RbCl-RbF flux at 850 degrees C. This is the first report of rubidium-based mixed-metal titanium hollandite materials grown as single crystals. All compounds crystallize in the tetragonal space group I4/m in the hollandite structure type featuring a three-dimensional framework, composed of mixed Ti/M octahedra, containing square, 2 x 2 tunnels occupied by the Rb cations. Herein, we report on the molten salt-flux crystal growth and solid state synthesis of the phases, the structures of the flux grown crystals, and the magnetic and optical properties of these materials. Magnetization versus temperature measurements for the Fe, Ni, and Cu analogues indicate that all compositions are Curie paramagnets with effective magnetic moments consistent with their respective d-electron count. First-principles calculations in the form of density functional theory were performed to calculate the relative stability, adsorption indexes, and the density of states for select compositions, all of which exhibit stability at 0 K with the computed optical band gaps consistent with the observations.

Twenty new alkali rare earth thiosilicates and thiogermanates with the general formula ALnTS4 (A = alkali metal, Ln = lanthanide, and T = Si, Ge) were grown as X-ray diffraction-quality single crystals from molten alkali chloride fluxes. These include KNdSiS4, KPrSiS4, RbLnSiS4 (Ln = Ce, Pr, Nd, Gd, Tb, Dy, and Ho), RbLaGeS4, CsLnSiS4 (Ln = La, Pr, and Nd), and CsLnGeS4 (La, Ce, Pr, Nd, Eu, Gd, and Tb). Herein, we discuss the use of a molten chloride flux growth approach for the preparation of the title compounds and their structure determination via single-crystal X-ray diffraction. In addition, we comment on the magnetic properties of RbNdSiS4, CsNdSiS4, CsNdGeS4, and CsGdGeS4, which were found to be paramagnetic for T = 2-300 K and exhibited negative Weiss temperatures with no obvious antiferromagnetic transition down to 2 K. The optical properties of CsLaGeS4 and CsNdTS4(T = Si, Ge) were measured by UV-vis spectroscopy. Second harmonic generation measurements performed on CsLaGeS4 confirmed the crystallization of the compound in the noncentrosymmetric orthorhombic space group, P212121; CsLaGeS4 was found to be SHG-active with nearly half the intensity of α-SiO2 upon irradiation with a Nd:YAG 1064 nm laser, and a semiconductor exhibiting a band gap of 3.60 eV based on UV-vis diffuse reflectance measurements.

Single crystals of nine new quaternary and penternary rare earth containing thiophosphates, Cs2KLn(PS4)2, Rb3-xNaxLn(PS4)2 (Ln = La, Nd), Rb2NaNd(PS4)2, Cs3La(PS4)2, Rb3Gd(PS4)2, and Cs5NaLn2(PS4)4 (Ln = Gd, Tb), were grown in alkali halide eutectic fluxes. All title compounds were structurally characterized by single crystal X-ray diffraction and were found to crystallize in pseudo one-dimensional structure types, reminiscent of those found for other known alkali rare earth thiophosphates, in a variety of space groups including monoclinic P21/c, P21/m, P21 and orthorhombic Ccca. The crystal structures of the reported compounds are characterized by the formation of complex one-dimensional [(Ln(PS4)2)3-] and [(Ln2(PS4)4)6-] anionic chains that run along the crystallographic a-axis in Cs2KLn(PS4)2, Rb3-xNaxLn(PS4)2 (Ln = La, Nd) and Rb2NaNd(PS4)2, b-axis in Cs3La(PS4)2 and Rb3Gd(PS4)2, and c-axis in Cs5NaLn2(PS4)4 (Ln = Gd, Tb). Cs2KLn(PS4)2, Rb3-xNaxLn(PS4)2, (Ln = La, Nd), Rb2NaNd(PS4)2, Rb3Gd(PS4)2 and C...

La2USe3S2, exact composition La2USe2.96S2.04, crystallized from a reaction between USe2 and La2S3 in a molten CsCl/KCl eutectic flux and was characterized by single crystal X-ray diffraction. La2USe3S2 crystallizes in the orthorhombic space group Pnma in the U3S5 structure type with lattice parameters a = 12.3284(3) Å, b = 8.4028(2) Å, and c = 7.3452(2) Å. In La2USe3S2 all the anion sites have mixed S and Se occupancy and, henceforth, will be simply referred to as Q sites. The compound exhibits sigmoidal sheets built from LaQ8 (Q = S, Se) bicapped trigonal prisms that edge-share down the a-axis forming rectangular-shaped channels or tunnels. These tunnels are occupied by UQ6 (Q = S, Se) octahedra that edge-share to form infinite, one-dimensional chains running down the b-axis. X-ray diffraction quality single crystals of La2USe3S2 were grown from a molten CsCl/KCl eutectic flux at 950 °C and used for structure determination using single crystal X-ray diffraction. The compound crystallizes in the orthorhombic space group Pnma in the U3S5 structure type.

A series of rare earth uranates, RE6UO12-delta (RE = La, Nd, Sm - Dy, Er and Yb), were synthesized via the solid state method and their structures were determined using the Rietveld method. These compounds crystallize in the rhombohedral space group R-3H with the lattice parameters a = 10.47005(3) angstrom and c = 9.98034(3) angstrom for the La analogue. The temperature and field dependent magnetization are reported for each analogue. Antiferromagnetic ordering is observed for RE = Gd, Tb, and Dy with Neel temperatures of 2.1 K, 5.8 K, and 2.8 K, respectively. Magnetic measurements on the La6UO12 analogue indicate the presence of some U5+, and therefore, oxygen vacancies in the structure. The variability of the U valence is examined.

A family of alkali uranium(IV) phosphates, AU(2)(PO4)(3) (A = Li - Cs), was synthesized as single crystals by the reaction of US2 and (NH4)(2)HPO4 in the respective ACl (A = Li - Cs) flux contained in a sealed fused-silica tube at 850 degrees C, and as phase pure powders from a similar reaction using UF4 as the uranium source. AU(2)(PO4)(3) (A = Li - Rb) crystallize in the NaTh2(PO4)(3) (NTP) structure type with monoclinic space group C-2/c and consist of a 3D structure that features a framework composed of edge- and corner-sharing polyhedra. The cesium analogue, CsU2(PO4)(3), crystallizes in a different structure with space group P2(1)/n that is related to the NaZr2(PO4)(3) (NZP) structure type and consists of a framework composed of corner-sharing polyhedra. Two new alkali uranium phosphates, Li2U(PO4)(2) and Cs4U4(P2O7)(5), were also grown as single crystals at 700 degrees C. Li2U(PO4)(2) was isolated in approximately 30% yield based on uranium. Li2U(PO4)(2) crystallizes in space group P2(1)/c exhibiting a layered structure while Cs4U4(P2O7)(5), crystallizes in space group P2(1)/n in a new structure type featuring a 3D framework. The magnetic susceptibilities and the field dependent magnetizations were measured for AU(2)(PO4)(3) (A = Li, Na, K and Cs); all compounds exhibited negative Weiss temperatures with no obvious antiferromagnetic transition. Optical properties were measured by UV-vis and IR spectroscopy.