The reliable and straightforward fabrication of nanoparticles is essential for developing future nanotechnology. [1][2][3][4][5] Nanoscale transition-metal oxides provide a wide spectrum of important properties, [6,7] and their functionalization and alignment is greatly facilitated by anisotropic morphologies. [8] Among the transition-metal oxides, MoO 3 is the focus of much attention owing to its numerous applications, for example, in catalysis [9][10][11] or sensor technology. [12,13] We have recently developed a solvothermal procedure that provides a convenient access to highly anisotropic nanoscale MoO 3 fibers. [14,15] The solvothermal process [16] is famous for its unique control facilities regarding the particle size of the material produced. [17,18] Its major drawback, however, is that the predictive and rational preparation of a desired solid remains a major preparative challenge-especially if the morphology of the product is to be tuned as well. This problem is because of the tremendous impact of the synthetic parameters on the course of the reaction. Thus, the development of solvothermal nanomaterials syntheses may require considerable "trial and error" work. The elucidation of solvothermal reaction mechanisms is therefore vital for devising more predictive strategies so that the resulting materials can be optimized for commercial purposes. As solvothermal reactions are usually performed in thick-walled reaction containers, sophisticated in situ techniques employing high-intensity synchrotron radiation are required for their direct monitoring. [19][20][21][22] Generally, the development of high-pressure, in situ spectroscopic approaches is a challenging topic of chemistry and materials science. [23] Orientating kinetic studies may also be performed by quenching hydrothermal reactions, but this information is only valid if the recovered material is not affected by any irreversible changes upon cooling and isolation. Among the multitude of solvothermally generated materials, special emphasis has been placed upon the in situ study of zeolites, [24][25][26] open-framework compounds, [27,28] silicate minerals, [29,30] and sulfide-based systems. [22,31] For the transitionmetal oxides, the main focus has been on ternary compounds of industrial interest (e. g. bismuth molybdates [32] or BaTiO 3[33] ), whereas considerably fewer binary oxides (such as ZrO 2 [34] ) have been investigated by solvothermal in situ methods. Very little mechanistic information is available on their solvothermal transformation into nanomaterials.Herein, we report the first comprehensive in situ study on the growth of MoO 3 fibers by complementary EDXRD (energy dispersive X-ray diffraction) and XANES/EXAFS (X-ray absorption near edge structure/extended X-ray absorption fine structure) techniques. While XRD allows the long-range order to be monitored, XANES/EXAFS provides information on the short-range order. [35][36][37] This information is indispensable for describing the solvothermal crystallization of nanostructured matter, because ...

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A hydrothermal approach employing an amine as reducing agent enables synthesis of an analogue of the arsenato(iii)-oxovanadate {V(15)As(6)}, representing the first systematic variation of this intensely studied magnetic system.

Four new thioantimonate(III) compounds with the general formula [TM(tren)]Sb4S7, TM = Mn 1, Fe 2, Co 3 and Zn 4, were synthesized under solvothermal conditions by reacting elemental TM, Sb and S in an aqueous solution of tren (tren = tris(2‐aminoethyl)amine). All compounds crystallize in the monoclinic space group P21/n with four formula units in the unit cell. Single crystal X‐ray analyses of 1 [a = 8.008(2), b = 10.626(2), c = 25.991(5) Å, β = 90.71(3)°, V = 2211.4(8) Å3], 2 [a = 8.0030(2), b = 10.5619(2), c = 25.955(5) Å, β = 90.809(3)°, V = 2193.69(8) Å3], 3 [a = 7.962(2), b = 10.541(2), c = 25.897(5) Å, β = 90.90(3)°, V = 2173.0(8) Å3] and 4 [a = 7.978(2), b = 10.625(2), c = 25.901(5) Å, β = 90.75(3)°, V = 2195.2(8) Å3] reveal that the compounds are isostructural. The [Sb4S7]2‐ anions are composed of three SbS3 trigonal pyramids and one SbS4 unit as primary building units (PBU). The PBUs share common edges and corners to form semicubes (Sb3S4) which may be regarded as secondary building units (SBU). The SBUs and SbS3 pyramids are joined in an alternating fashion yielding the [Sb4S7‐] anionic chain which is directed along [100]. Weaker Sb‐S bonding interactions between neighbored chains lead to the formation of layers within the (001) plane which contain pockets that are occupied by the cations. The TM2+ ions are in a trigonal bipyramidal environment of four N atoms of the tren ligand and one S atom of the thioantimonate(III) anion. The optical band gaps depend on the TM2+ ion and amount to 3.11 eV for 1, 2.04 eV for 2, 2.45 eV for 3, and 2.60 eV for 4.