Structural and Physical Properties Diversity of New CaCu5-Type Related Europium Platinum Borides
- Author(s)
- Leonid P. Salamakha, Ernst Bauer, Gerfried Hilscher, Herwig Michor, Oksana Sologub, Peter Franz Rogl, Gerald Giester
- Abstract
Three novel europium platinum borides have been synthesized by arc melting of constituent elements and subsequent annealing. They were characterized by X-ray powder and single-crystal diffraction: EuPt4B, CeCo4B type, P6/mmm, a = 0.56167(2) nm, c = 0.74399(3) nm; Eu3Pt7B2, Ca3Al7Cu2 type as an ordered variant of PuNi3, R3m, a = 0.55477(2) nm, c = 2.2896(1) nm; and Eu5Pt18B6-x, a new unique structure type, Fmmm, a = 0.55813(3) nm, b = 0.95476(5) nm, c = 3.51578(2) nm. These compds. belong to the CaCu5 family of structures, revealing a stacking sequence of CaCu5-type slabs with different structural units: CaCu5 and CeCo3B2 type in EuPt4B; CeCo3B2 and Laves MgCu2 type in Eu3Pt7B2; and CaCu5-, CeCo3B2-, and site-exchange ThCr2Si2-type slabs in Eu5Pt18B6-x. The striking motif in the Eu5Pt18B6-x structure is the boron-centered Pt tetrahedron [BPt4], which build chains running along the a axis and plays a decisive role in the structure arrangement by linking the terminal fragments of repeating blocks of fused Eu polyhedra. Phys. properties of two compds., EuPt4B and Eu3Pt7B2, were studied. Both compds. were found to order magnetically at 36 and 57 K, resp. For EuPt4B a mixed-valence state of the Eu atom was confirmed via magnetic and sp. heat measurements. Moreover, the Sommerfeld value of the sp. heat of Eu3Pt7B2 was found to be extraordinarily large, on the order of 0.2 J/mol K2.
- Organisation(s)
- Department of Physical Chemistry, Department of Mineralogy and Crystallography
- External organisation(s)
- Technische Universität Wien, Instituto Superior Técnico
- Journal
- Inorganic Chemistry
- Volume
- 52
- Pages
- 4185-4197
- No. of pages
- 13
- ISSN
- 0020-1669
- DOI
- https://doi.org/10.1021/ic301548w
- Publication date
- 2013
- Peer reviewed
- Yes
- Austrian Fields of Science 2012
- 104017 Physical chemistry, 105113 Crystallography
- Portal url
- https://ucrisportal.univie.ac.at/en/publications/d155eb73-61a1-4f51-b142-307b8fabdf27