Superstructure formation in PrNi2Al3 and ErPd2Al3

Eustermann, Fabian; Hoffmann, Rolf‐Dieter; Janka, Oliver

doi:10.1515/zkri-2016-2023

Cited by 8 publications

(5 citation statements)

References 23 publications

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“…Hence, they are shifted by 1/2 z compared to the original position. The same shift is also observed in YNi 2 Al 3 [16,35] and i7-PrNi 2 Al 3 [17]. Refinement as orthorhombic trilling, as suggested by the translationengleiche symmetry reduction of index 3, is not necessary because the orthorhombic crystal system was found directly by the indexing routine.…”

Section: Structure Refinementssupporting

confidence: 60%

“…From a crystal chemical point of view, YNi 2 Al 3 is also worth mentioning [16], because this compound can be considered to be an i3-superstructure of the PrNi 2 Al 3 -type structure. Recently, an i7-superstructure of PrNi 2 Al 3 has also been reported, which was also found for ErPd 2 Al 3 [17]. Our interests in the compounds of the REPt 2 Al 3 series originate from the fact that only CePt 2 Al 3 (PrNi 2 Al 3 -type) has been reported previously [18].…”

Section: Introductionmentioning

confidence: 72%

“…Three crystallographically distinct Y 3+ cations can be found in the cavities of the polyanion. They exhibit 18-fold coordination environments in the shape of six-fold-capped hexagonal prisms (Figure 4 A view of the unit cell along the c axis readily reminds us of the ternary CaCu 5 [14], and the recently found i7 superstructure of PrNi 2 Al 3 [17]. Recoloring in intermetallics is found quite frequently, often accompanied by distortions and puckering within the respective structures [35].…”

Section: Structure Refinementsmentioning

confidence: 90%

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Crystal Structure, Spectroscopic Investigations, and Physical Properties of the Ternary Intermetallic REPt2Al3 (RE = Y, Dy–Tm) and RE2Pt3Al4 Representatives (RE = Tm, Lu)

et al. 2018

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Abstract:The REPt 2 Al 3 compounds of the late rare-earth metals (RE = Y, Dy-Tm) were found to crystallize isostructural. Single-crystal X-ray investigations of YPt 2 Al 3 revealed an orthorhombic unit cell (a = 1080.73(6), b = 1871.96(9), c = 413.04(2) pm, wR2 = 0.0780, 942 F 2 values, 46 variables) with space group Cmmm (oC48; q 2 pji 2 hedb). A comparison with the Pearson database indicated that YPt 2 Al 3 forms a new structure type, in which the Pt and Al atoms form a [Pt 2 Al 3 ] δ− polyanion and the Y atoms reside in the cavities within the framework. Via a group-subgroup scheme, the relationship between the PrNi 2 Al 3 -type structure and the new YPt 2 Al 3 -type structure was illustrated. The compounds with RE = Dy-Tm were characterized by powder X-ray diffraction experiments. While YPt 2 Al 3 is a Pauli-paramagnet, the other REPt 2 Al 3 (RE = Dy-Tm) compounds exhibit paramagnetic behavior, which is in line with the rare-earth atoms being in the trivalent oxidation state. DyPt 2 Al 3 and TmPt 2 Al 3 exhibit ferromagnetic ordering at T C = 10.8(1) and 4.7(1) K and HoPt 2 Al 3 antiferromagnetic ordering at T N = 5.5(1) K, respectively. Attempts to synthesize the isostructural lutetium compound resulted in the formation of Lu 2 Pt 3 Al 4 (Ce 2 Ir 3 Sb 4 -type, Pnma, a = 1343.4(2), b = 416.41(8), c = 1141.1(2) pm), which could also be realized with thulium. The structure was refined from single-crystal data (wR2 = 0.0940, 1605 F 2 values, 56 variables). Again, a polyanion with bonding Pt-Al interactions was found, and the two distinct Lu atoms were residing in the cavities of the [Pt 3 Al 4 ] δ-framework. X-ray photoelectron spectroscopy (XPS) measurements were conducted to examine the electron transfer from the rare-earth atoms onto the polyanionic framework.

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Section: Structure Refinementssupporting

confidence: 60%

Section: Introductionmentioning

confidence: 72%

Section: Structure Refinementsmentioning

confidence: 90%

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Crystal Structure, Spectroscopic Investigations, and Physical Properties of the Ternary Intermetallic REPt2Al3 (RE = Y, Dy–Tm) and RE2Pt3Al4 Representatives (RE = Tm, Lu)

et al. 2018

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“…At first sight one might assume isotypism with PrNi 2 Al 3 , [8] however, YNi 2 Al 3 adopts a superstructure, caused by a displacement of one third of the yttrium atoms. This displacement pattern also occurs for the sevenfold superstructures of i7‐PrNi 2 Al 3 and ErPd 2 Al 3 [9] …”

Section: Introductionmentioning

confidence: 56%

“…This displacement pattern also occurs for the sevenfold superstructures of i7-PrNi 2 Al 3 and ErPd 2 Al 3 . [9] Even though the CaCu 5 family has numerous representatives, so far not all element combinations and distortions variants are known. During recent phase analytical studies in the RE-Pd-Zn systems we obtained the series of REPd 2 Zn 3 (RE = Y, La-Nd, Sm, Gd-Dy) phases [10,11] that adopt the parent structure with palladium-zinc ordering.…”

Section: Introductionmentioning

confidence: 99%

APd₂Zn₃ (A=Ca, Sr, Eu) with a CaCu₅ superstructure

Pöttgen

Gerke

Niehaus

et al. 2022

Zeitschrift anorg allge chemie

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The intermetallic phases APd2Zn3 (A=Ca, Sr, Eu) were synthesized from the elements in sealed niobium ampules in an induction furnace. The phase purity of the samples was checked by powder X‐ray diffraction (Guinier technique). The structures were refined from single crystal X‐ray diffractometer data: YNi2Al3 type (CaCu5 superstructure), P6/mmm, a=936.97(4), c=420.75(2) pm, wR2=0.0206, 259 F2 values, 17 variables for CaPd2Zn3, a=953.63(6), c=425.38(3) pm, wR2=0.0185, 230 F2 values, 17 variables for SrPd2Zn3 and a=948.20(7), c=423.20(3) pm, wR2=0.0209, 228 F2 values, 18 variables for EuPd2.12(1)Zn2.88(1). The europium‐based crystal showed a small homogeneity range through Pd/Zn mixing. The striking structural motifs of the APd2Zn3 phases are Kagome networks formed by the palladium and zinc atoms. The superstructure formation (discussed on the basis of a Bärnighausen tree) results from a different Pd/Zn coloring and a shift of one A position by c/2. The divalent character of europium in EuPd2Zn3 was substantiated by magnetic susceptibility and 151Eu Mössbauer spectroscopic measurements. EuPd2Zn3 orders ferrimagnetically at TC=17.5(5) K. The magnetization behavior at 3 K (two‐step magnetization) confirms the existence of two crystallographically independent europium sites. The 151Eu Mössbauer spectrum at 5 K shows full magnetic hyperfine field splitting (δ=−8.99(4) mm s−1 and BHf=27.7(1) T).

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