[NiEn3](MoO4)0.5(WO4)0.5 Co-Crystals as Single-Source Precursors for Ternary Refractory Ni–Mo–W Alloys

Abstract

The co-crystallisation of [NiEn3](NO3)2 (En = ethylenediamine) with Na2MoO4 and Na2WO4 from a water solution results in the formation of [NiEn3](MoO4)0.5(WO4)0.5 co-crystals. According to the X-ray diffraction analysis of eight single crystals, the parameters of the hexagonal unit cell (space group P–31c, Z = 2) vary in the following intervals: a = 9.2332(3)–9.2566(6); c = 9.9512(12)–9.9753(7) Å with the Mo/W ratio changing from 0.513(3)/0.487(3) to 0.078(4)/0.895(9). The thermal decomposition of [NiEn3](MoO4)0.5(WO4)0.5 individual crystals obtained by co-crystallisation was performed in He and H2 atmospheres. The ex situ X-ray study of thermal decomposition products shows the formation of nanocrystalline refractory alloys and carbide composites containing ternary Ni–Mo–W phases. The formation of carbon–nitride phases at certain stages of heating up to 1000 °C were shown.

The development of an approach for the precision determination of thermal strain tensor elements for single crystals using the example of t-Ag0.8Li0.2InSe2

“…7 Characterization of solid solutions of phases with close UCP is another task that cannot always be solved with polycrystalline diffractometry data due to the broadening of diffraction lines, even using synchrotron radiation. 8 In the case of single crystals, there is no problem of overlapping diffraction lines, and the theoretical determination of the thermal expansion coefficient can be carried out with high accuracy. However, such accuracy is not achieved during routine experiments using modern diffractometers and synchrotron radiation stations equipped with 2D detectors.…”

“…7 Characterization of solid solutions of phases with close UCP is another task that cannot always be solved with polycrystalline diffractometry data due to the broadening of diffraction lines, even using synchrotron radiation. 8…”

Insight into the Structure and Redox Chemistry of [Carbonatotetraamminecobalt(III)] Permanganate and Its Monohydrate as Co-Mn-Oxide Catalyst Precursors of the Fischer-Tropsch Synthesis

“…An easy and convenient reaction route for the preparation of the simple and mixed nanosized transition metal oxides [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18]-especially for the synthesis of catalytically active spinel oxides [19][20][21][22][23][24][25][26][27][28][29][30]-is the thermal decomposition of complexes having reducing ligands and oxidizing anions [31][32][33][34][35][36][37][38]. These processes consisted of a solid-phase quasiintramolecular redox reaction between an oxidizing anion and a reducing ligand.…”

Review on the Chemistry of [M(NH3)n](XO4)m (M = Transition Metal, X = Mn, Tc or Re, n = 1–6, m = 1–3) Ammine Complexes

“…The temperature-controlled decomposition of transition metal complexes containing redox-active central atoms, ligands, and anions in solid-phase quasi-intramolecular redox reactions has become a widely used method of preparing nano-sized oxides, nitrides, carbides, metals, and their alloys [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]. The reducing ligands (pyridine, urea, or ammonia) and oxidizing anions containing precursors frequently give amorphous decomposition intermediates, which can be transformed into controlled-sized crystalline materials by heat treatment [7,[10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28].…”