12066-81-8Relevant articles and documents
Phase relations in the Al-Pr-Sb system at 773 K
Zeng, Lingmin,Liao, Jiangping,Qin, Pingli,Qin, Haiqing,Nong, Liangqin
, p. 252 - 254 (2008)
The isothermal section of the phase diagram of the Al-Pr-Sb ternary system at 773 K over the whole concentration region has been investigated mainly by powder X-ray diffraction (XRD) with the aid of scanning electron microscopy (SEM). A new ternary compound ～Al11Pr24Sb65 has been found.
Synthesis and Transport Properties of the Family of Zintl Phases Ca3RESb3(RE = La-Nd, Sm, Gd-Tm, Lu): Exploring the Roles of Crystallographic Disorder and Core 4f Electrons for Enhancing Thermoelectric Performance
Ogunbunmi, Michael O.,Baranets, Sviatoslav,Bobev, Svilen
, p. 9382 - 9392 (2021/12/13)
Zintl phases with complex crystal structures have been studied as promising candidate materials for thermoelectric (TE) applications. Here, we report the syntheses of the family of rare-earth metal Zintl phases with the general formula Ca4-xRExSb3 (x ≈ 1; RE = La-Nd, Sm, Gd-Tm, Lu). The structural elucidation is based on refinements of single-crystal X-ray diffraction data for 12 unique chemical compositions. The cubic structure is confirmed as belonging to the anti-Th3P4 structure type (space group I4ˉ 3d, no. 220, Z = 4), where the Ca and RE atoms share the same atomic site with ca. 75 and 25% occupancies, respectively. Such crystallographic disordering of divalent Ca and trivalent RE atoms in the structure provides a pathway to intricate bonding. The latter, together with the presence of heavy elements such as Sb and the lanthanides, are expected to enhance the scattering probability of phonons, thereby leading to low thermal conductivity κ comparable to that of the ordered RE4Sb3. The drive of the hypothetical parent compound Ca4Sb3 to be stabilized by alloying with rare-earth metals can be understood following the Zintl-Klemm concept, as the resultant formula may be rationalized as (Ca2+)3RE3+(Sb3-)3, indicating the realization of closed-shell electronic configurations for all elements. This notion is confirmed by electronic structure calculations, which reveal narrow bandgaps Eg = 0.77 and 0.53 eV for Ca3LaSb3 and Ca3LuSb3, respectively. In addition, the incorporation of RE atoms into the structure drives the phase into a state of a degenerate semiconductor with dominant hole charge carriers.
New ternary La2Sb-type compounds, ScRESb (RE = La, Ce, Pr, Nd, Sm, Tb), and the oxygen stuffed variant Sc4Yb4Sb 4O
Nuss, Juergen,Jansen, Martin
, p. 713 - 718 (2014/04/17)
Scandium rare-earth metal antimonides, ScRESb (RE = La, Ce, Pr, Nd, Sm, Tb) were synthesized from scandium metal and binary RESb at 1770 K in tantalum ampoules. According to X-ray analyses of the crystal structures, they adopt the tetragonal ScCeSi-type of structure (space group I4/mmm, Pearson code tI12), a variant of La2Sb, with a fully ordered atom distribution. Especially in ScSmSb and ScTbSb, the scandium atoms are distorted from an ideal 4 4 net in a way to form Sc nets of squares and rhombi in order to adjust to the lattice shrinkage in the ab plane, caused by the lanthanide contraction. Finally the structure changes from La2Sb to Sc 2Sb-type (anti-PbFCl-type), when terbium is replaced by dysprosium. The respective compound with ytterbium was only found when stoichiometric amounts of oxygen were present, resulting in Sc4Yb4Sb 4O, a La2Sb-type variant stuffed with oxygen. A structure field map, based on specific geometric parameters, easily allows for distinguishing between oxygen stuffed and oxygen-free compounds. Magnetic susceptibility measurements of ScCeSb, ScPrSb, and ScNdSb indicate Curie-Weiss behavior with ferromagnetic exchange coupling underlying. The magnetic moments correspond to the expected values for RE3+. Copyright
