24600-77-9Relevant academic research and scientific papers
Octaammine EuIIand YbIIAzides and Their Thermal Decompositions to the Nitrides
Müller, Thomas G.,Mogk, Jochen,Conrad, Matthias,Kraus, Florian
, p. 4162 - 4169 (2016/09/16)
The common preparation for many nitrides is the synthesis from the corresponding metals and nitrogen at quite high temperatures and/or high pressures. Here we present a route to metal nitrides by the use of ammine metal azides under relatively mild conditions. Europium(II) and ytterbium(II) azides are prepared in liquid ammonia at –36 °C in form of their temperature-sensitive octaammine complexes. These were investigated by single-crystal X-ray diffraction at low temperatures, and their structures seem to be the first evidence for the existence of homoleptic ammine EuIIand YbIIcomplexes, as well as that the coordination number of these divalent cations can go beyond six with NH3ligands. In one of the cases presented here the observed coordination polyhedron is better described as a bicapped trigonal prism (C2v), in one case better as square-antiprismatic (D4d). Warming of these compounds to room temperature leads to the lanthanoid metal azides still containing approximately 1 equiv. of ammonia. The behaviour of these azides towards further heating was investigated: By very careful and slow decomposition, the nitrides of europium(III) and ytterbium(III) are obtained at only 230 °C at ambient pressure. This method may be suitable to obtain other metal nitrides at remarkably low temperatures and pressures.
Preparation and characteristics of various rare earth nitrides
Imamura,Imahashi,Zaimi,Sakata
, p. 636 - 639 (2009/01/21)
Active nanocrystalline nitrides of EuN and YbN with high surface areas were successfully prepared by the thermal decomposition of the rare earth amides (Eu(NH2)2, Yb(NH2)2 and Yb(NH2)3). For the preparation of CeN, PrN and NdN, the direct reaction of the rare earth metals with ammonia was extensively studied to determine optimal conditions. In the reaction of rare earth metals with ammonia, hydrides besides the nitrides were competitively formed. The reaction conditions such as temperatures and ratios of ammonia to rare earth metal were crucial in preferential formation of nitride. The nanocrystalline YbN and EuN readily absorbed large amounts of ammonia even at room temperature upon contact with ammonia (13.3 kPa). The absorbed ammonia existed in at least two forms on/in the nitride; the one was surface-adsorbed ammonia and the other ammonia absorbed in the nitride in a decomposed state. The properties of ammonia absorbed by the nitride were further evaluated by temperature-programmed desorption (TPD), FT-IR and XRD techniques.
Rare-earth nickel nitridoborates with (BN) anions: Characterized RENi(BN) and anticipated REM(BN) compounds
Neukirch, Michael,Blaschkowski, Bjoern,Haeberlen, Marco,Meyer, H.-Juergen
, p. 1799 - 1803 (2008/10/09)
The compounds RENi(BN) with RE = Y, La, Ce, Pr, Tm and Yb were synthesized by solid state reactions from metal powders and α-BN at temperatures between 1000° and 1200 °C. In addition, the mixed phases (Ca, Yb)Ni(BN) and (Ca, Tm)Ni(BN) were synthesized. All products were characterized by powder XRD measurements and indexed isotypic with the structure of CaNi(BN), consistent with the tetragonal space group P4/nmm. The bonding conditions of the (BN) anion are discussed in a perspective view on new nitridoborate compounds REM(BN) containing transition metal atoms (M) other than Ni.
Preparation and properties of nanocrystalline ytterbium and europium nitride (YbN and EuN)
Imamura,Sakata,Nuruyu,Imahashi
, p. 251 - 254 (2008/10/09)
Nanocrystalline rare earth nitrides (EuN and YbN) were successfully prepared by the thermal decomposition of amides (Eu(NH2)2, Yb(NH2)2 and Yb(NH2)3). The formation processes of nanocrystal
Reactions of alkaline earth metals and nitrogen in sealed niobium ampoules: The formation of MgZn2 type intermetallic phases in the presence of nitrogen and the new compound Ba5[NbN4]N
Reckeweg, Olaf,Lind, Cora,Simon, Arndt,Disalvo, Francis J.
, p. 98 - 105 (2008/10/09)
Reactions between alkaline earth metals or their corresponding nitrides and NaN3 as nitrogen donor in cleaned sealed Nb ampoules at different temperatures yields known phases, 'β-Ca3N2' and single crystals in the form of transparent, orange plates of Ba 5[NbN4]N. The crystal structure of this new compound was determined by means of single crystal X-ray diffraction (C2/m (no. 12), a = 1231.7(3), b = 1094.6(2), c = 853.8(2) pm,β = 113.65(3) and Z = 4). At temperatures ≥ 1000°C, the available nitrogen apparently reacts with the Nb container walls and intermetallic phases are formed. The crystal structures of AeMg2 (MgZn2 type with Ae = Ca, Yb, Sr, Eu and Ba) were re-determined by X-ray single crystal structure analyses on crystals obtained in such reactions to ascertain the presence or absence of nitrogen in structural voids. The structures of the ternary nitride and intermetallic phases are described and compared to known compounds.
Selective dimerization of ethene over lanthanide catalysts deposited from Eu or Yb metal solutions in liquid ammonia
Imamura, Hayao,Kuhara, Takumi,Furutachi, Masataka,Sakamoto, Takahiko,Sakata, Yoshihisa
, p. 744 - 745 (2007/10/03)
Europium and ytterbium catalysts obtained by impregnation of active carbon with lanthanide metal (Eu and Yb) solutions in liquid ammonia were found to be active for the dimerization of ethene. Ethene was selectively dimerized at 423-473 K to yield butene isomers with selectivity of 10-62%. The active catalysts were characterized as lanthanide nitride formed by the thermal decomposition of its amide.
Specific heat of ytterbium monopnictides under magnetic fields
Li, D. X.,Oyamada, A.,Shida, H.,Suzuki, T.,Kasuya, T.,et al.
, (2008/10/08)
The specific heat of the ytterbium monopnictides YbX (X = N, P, As, Sb) measured in magnetic fields up to 10 T shows a different field dependence of the broad peak around 5 K in the four compounds. The zero-field data are analyzed with a new model including both Kondo effect and magnetic excitations.
Magnetic characteristics of some lanthanide nitrides
Schumacher, David P.,Wallace
, p. 1563 - 1567 (2008/10/08)
Magnetic susceptibilities (χ) of Y, La, Ce, Nd, Sm, Yb, Lu, and their nitrides were determined over a temperature range extending from 2 to 300°K. Y, La, and Lu and their nitrides are Pauli paramagnets. SmN orders antiferromagnetically below 13°K. NdN exhibits ferromagnetic ordering below 35°K. Its magnetic moment in the ferromagnetic state at 2°K is 2.15 μB, as contrasted with 3.3 μB for the free Nd3+ ion. The reduction is ascribed to crystal field quenching. From the measured moment an over-all splitting of the ground state Nd3+ ion multiplet is estimated to be 234°K. The effective moment of Nd in paramagnetic NdN is in good agreement with that expected for the free ion. YbN exhibits Curie-Weiss behavior at >100°K with a moment in fair agreement with that expected for the Yb3+ ion. However, the magnitude of χ for YbN and the low-temperature deviation from Curie-Weiss behavior are not understood. Results for Yb indicate 34% Yb3+ and 66% Yb2+. The CeN results indicate a mixture of Ce3+ and Ce4+ with the latter strongly predominating at low temperatures. In accordance with theoretical expectations no magnetic ordering is observed for CeN and YbN at temperatures down to 2°K.
