Synthesis and structure determination of Ce₆Cd₂₃Te: a new chalcogen-containing member of theRE₆Cd₂₃T family (REis a rare-earth metal and T is a late group 14, 15 and 16 element)

Abstract

The ternary phase hexacerium tricosacadmium telluride, CeCdTe, was synthesized by a high-temperature reaction of the elements in sealed Nb ampoules and was structurally characterized by powder and single-crystal X-ray diffraction. The structure, established from single-crystal X-ray diffraction methods, is isopointal with the ZrZnSi structure type (Pearson symbol cF120, cubic space group Fm-3m), a filled version of the ThMn structure with the same space group and Pearson symbol cF116. Though no Cd-containing rare-earth metal binaries are known to form with this structure, it appears that the addition of small amounts of a p-block element allows the formation of such interstitially stabilized ternary compounds. Temperature-dependent direct current (dc) magnetization measurements suggest local-moment magnetism arising from the Ce ground state, with possible valence fluctuations at low temperature, inferred from the deviations from the Curie-Weiss law.

Crystal Chemistry of RE6MgxCd23–xPb [0.6(1) ≤ x ≤ 3.2(1); RE = La and Ce]. New Mixed‐Metal Derivatives of the RE6Cd23T Phases (T = Group 14/15/16 Element)

“…Previous structural work on the RE 6 Cd 23 T family has shown slightly enlarged equivalent displacement parameters ( U eq ) at site Cd4 – systematically larger than for any other three Cd positions , . When examining the title compounds, however, it was found that the U eq at M 4 was not higher or lower than those of M 1–3 (Table ).…”

“…As mentioned previously, our recent work on the RE 6 Cd 23 T series of compounds enabled a fairly effortless workup of the title compounds. [21,22] Similar to RE 6 Cd 23 Pb, crystals of RE 6 Mg x Cd 23-x Pb (RE = La, Ce) were also brittle and exhibited a lustrous silver color. The attempted RE-Mg-Cd-Pb reactions gave good yields of the title compounds, albeit with visible impurity peaks.…”

“…The title compounds adopt the same structure as RE 6 Mg 23 T and RE 6 Cd 23 T -localized covalent RE 6 T clusters within an extended metallic Cd sub-structure. [20][21][22] Thus, many of the structural descriptions given in our earlier work still apply, to which we refer the reader for a more exhaustive description. [21,22] To maintain consistency with our previous work, all present discussion also follow the f 2 edba Wyckoff scheme, with position 4b occupied by Pb.…”

“…[20][21][22] Thus, many of the structural descriptions given in our earlier work still apply, to which we refer the reader for a more exhaustive description. [21,22] To maintain consistency with our previous work, all present discussion also follow the f 2 edba Wyckoff scheme, with position 4b occupied by Pb. [21,22] For the purposes of this publication we will use the labels M1/2/3/4 to respectively refer to those positions occupied by Cd1, Cd2, Cd3, and Cd4 in the ternary RE 6 Cd 23 T lattice (Wyckoff positions 2 ϫ 32f, 24d, and 4a) ( Figure 1).…”

“…[8,15] In the latter case, the four Mn 23 positions need not experience the same degree of mixed occupancy, and a more ordered distribution may be favored at certain sites due to electronic, magnetic, and/or volume effects. [15] Other literature findings suggest that the chemical make-up of the Mn 23 sub-structure greatly influences the compound's bulk properties, [6,[19][20][21][22] which may open ARTICLE the door for tuning of physical properties through substitutional chemistry.…”