Jonathan C. Fitzmaurice

Rapid, low energy synthesis of lanthanide nitrides

Abstract Thermal initiation (400°C) of the reaction between lithium nitride and anhydrous lanthanide halides produces lanthanide nitrides LnN (Ln = Y, La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb) via a rapid exothermic solid state metathesis reaction. Mixed lanthanide nitrides LnLn′N (LnLn′ = PrNd; DyHo; TbDy) are made by reaction of ground powders of LnCl 3 with Li 3 N. The lanthanide nitrides were characterized by X-ray powder diffraction, scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDXA), FTIR, magnetic moment measurement and microanalysis.

New routes to alkali-metal–rare-earth-metal sulfides

Ternary alkali-metal–rare-earth-metal sulfides, MRES2(M = Li, Na, K; RE = Y, La–Yb) were prepared by heating RECL3and M2S under an H2S–N2 atmosphere at 750–800 °C for 10 min. The ternary sulfides form thin, mostly coloured plates. The structures were characterised by X-ray powder diffraction, which revealed high-temperature cubic modifications for LiHoS2 and LiErS2. The disordered cubic form (NaCl type) was observed for LiLnS2(Ln = Pr–Er) and NaLnS2(Ln = La–Nd), while the ordered rhombohedral form (α-NaFeO2 type) was observed for LiYbS2, NaLnS2(Sm–Yb) and KLnS2(La–Yb). Alkali-metal–rare-earth-metal sulfides may also be synthesized from the rare-earth-metal chloride and alkali-metal halide under comparable conditions. Similarly, thermolysis of the rare-earth-metal sesquisulfide (γ-RE2S3), oxysulfide (RE2O2S) or oxychloride (REOCL) with M2S or MCI in an atmosphere of H2S-N2 gives MRES2. The materials were characterised by powder X-ray diffraction, scanning electron microscopy (SEM), energy dispersive analysis by X-rays (EDXA), Raman, infrared, magnetic moments and microanalysis.

Organo-phosphorus–selenium heterocycles

Reaction of selenium with (PhP)5, or Li2Se with PhPCl2, gives a reactive intermediate (1) which undergoes reaction with acetone or CS2 to give new organo-phosphorus–selenium heterocycles which have been characterised by X-ray crystallography.

Rapid synthesis of TiN, HfN and ZrN from solid-state precursors

Abstract Microwave or conventional oven initiation of the reaction between lithium nitride and anhydrous metal chloride (M = Ti, Zr, Hf) produces metal nitride NM, dinitrogen and lithium chloride via a metathesis reaction. The metal nitrides were characterized by X-ray powder diffraction, SEM, EDAX, IR, magnetic moment measurement and micro-analysis.

The preparation of mixed-ligand dithiolene complexes: X-ray structure of Pt(PMe2Ph)2(mnt) and [Bu4N][Au(mnt)2]

Abstract Reaction Of PtCl2(PR3)2 with sodium dithiolates gives mixed-ligand complexes such as Pt(PR3)2(mnt) (1). Attempts to prepare mixed SN/mnt complexes of gold were unsuccessful, [Bu4N][Au(mnt)2] (2) being obtained. New compounds were characterized by IR and NMR spectroscopy and microanalyses, and in the case of 1 and 2 by X-ray crystallography. Both 1 and 2 are square planar. In 2, one of the crystallographically independent anions lies over a symmetry related neighbour.

SYNTHESIS OF METAL SILICIDE POWDERS BY THERMOLYSIS OF METAL CHLORIDES WITH MAGNESIUM SILICIDE

Abstract Thermolysis (850°C) of a mixture of Mg2Si and MCl13, (M = Y, Gd, Dy, Ho, Ti, Zr, Hf, Nb, Ta, Mo, W, Fe, Pt; n = 3, 4, 5) produces metal silicides MxSiy as microcrystalline powders. The reactions give a useful insight into the mechanisms working in this type of reaction.

Metathesis routes to lanthanide pnictides

Reaction of Na3As or Na3Sb with anhydrous LnCl3(Ln = Y, La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tb, Yb) at 500–900 °C in sealed Pyrex or quartz ampoules produces crystalline lanthanide arsenides or stibides (LnAs, LnSb, Eu2Sb3, Yb5Sb4), in good yields (70–90%), via, metathesis reactions. Mixed lanthanide arsenides and stibides, Ln0.5Ln′0.5E, (LnLn′= DyEr, NdPr; E = As; LnLn′= LaY, TbHo, TbEr, LaHo and PrHo; E = Sb) are made in a similar fashion by combining mixed lanthanide halide powders with Na3As or Na3Sb and initiating the reaction at 800 °C. Solid solutions of LnAsxPy and LnSbxAsy(Ln = Dy, Sm, Tb; x+y= 1) are made analogously using Na3AsxPy and Na3SbxAsy as starting materials. Lanthanide bismuthides (LnBi), can be made from LnCl3 and Na3Bi; however, decomposition to Ln metal and bismuth occurs on trituration with methanol. The lanthanide arsenides, lanthanide stibides, mixed lanthanide arsenides and mixed lanthanide pnictides were characterised by X-ray powder diffraction (XRD), microanalysis, scanning electron microscopy (SEM), energy dispersive X-rays analysis (EDXA), FTIR and magnetic-moment measurements.

Low-temperature routes to early transition-metal nitrides

Thermal initiation of the reaction of lithium nitride with anhydrous transition-metal halides produces crystalline transition-metal nitrides of various compositions MxNy(M = Y, La, Ti, Zr, Hf, V, Nb, Ta, Cr or Mn)via an exothermic solid-state metathesis reaction. Reaction of anhydrous late transition-metal halides with lithium nitride produces the metal (M = Mo, W, Fe, Co, Ni, Cu, Pt, Zn or Cd), dinitrogen and lithium halide. The metal nitrides were purified by tetrahydrofuran trituration and characterised by X-ray powder diffraction, scanning electron microscopy, energy dispersive analysis with X-rays, magnetic moment measurements, FTIR spectroscopy and microanalysis.

Preparation, crystal structures, conductivities and electronic structures of [et]3[NiCl4]·H2O and [et]3[AuBr4][et = bis(ethylenedithio)tetrathiafulvalene]

Single-crystal studies of [et]3[NiCl4]·H2O and [et]3[AuBr4][et = bis(ethylenedithio)tetrathiafulvalene] have revealed distinctly different packing motifs associated with the different anions. The nickel compound contains a sheet stack structure whilst the gold compound has a herringbone stack of et molecules. The stacking properties are discussed in the context of conductivity and band-theory calculations. The nickel compound exhibits metallic behaviour at room temperature.

Low temperature routes to europium and ytterbium chalcogenides

Reaction of europium or ytterbium metal in liquid ammonia with sulphur, selenium or tellurium (at room temperature in a pressure tube) affords a convenient route to crystalline binary metal chalcogenides.