The ternary platinides CaGa5Pt3 and EuGa5Pt3

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Judith Bönnighausen ◽  
Stefan Seidel ◽  
Steffen Klenner ◽  
Rainer Pöttgen
Keyword(s):  
Induction Furnace ◽  
Three Dimensional ◽  
Covalent Bonding ◽  
Intermetallic Phases ◽  
Temperature Dependent ◽  
X Ray ◽  
Antiferromagnetic Ordering ◽  
Divalent Europium ◽  
Experimental Magnetic Moment ◽  
Magnetic Hyperfine Splitting

Abstract The ternary platinides CaGa5Pt3 (a = 2082.5(4), b = 406.05(8), c = 739.2(1) pm) and EuGa5Pt3 (a = 2085.5(5), b = 412.75(9), c = 738.7(1) pm) were synthesized from the elements in sealed high-melting metal tubes in an induction furnace. CaGa5Pt3 and EuGa5Pt3 are isotypic with CeAl5Pt3 and isopointal with the YNi5Si3 type intermetallic phases (space group Pnma, oP36 and Wyckoff sequence c 9). The structure of EuGa5Pt3 was refined from single crystal X-ray diffractometer data: wR2 = 0.0443, 1063 F 2 values and 56 variables. The gallium and platinum atoms build up a three-dimensional [Ga5Pt3]2− polyanionic network in which the europium atoms fill slightly distorted hexagonal prismatic voids. The Ga–Pt distances within the network range from 249 to 271 pm, emphasizing the covalent bonding character. Temperature dependent magnetic susceptibility measurements indicate diamagnetism for CaGa5Pt3 and isotypic BaGa5Pt3. EuGa5Pt3 behaves like a Curie–Weiss paramagnet above 50 K with an experimental magnetic moment of 8.17(1) µB/Eu atom, indicating divalent europium. Antiferromagnetic ordering sets in at T N = 8.5(1) K. The divalent ground state of europium is confirmed by 151Eu Mössbauer spectroscopy. EuGa5Pt3 shows a single signal at 78 K with an isomer shift of −9.89(4) mm s−1. Full magnetic hyperfine splitting with a hyperfine field of 25.0(2) T is observed at 6 K in the magnetically ordered regime.

Antiferromagnetic ordering in the plumbide EuPdPb

2017 ◽  
Vol 72 (12) ◽  
pp. 989-994
Author(s):  
Lukas Heletta ◽  
Steffen Klenner ◽  
Theresa Block ◽  
Rainer Pöttgen
Keyword(s):  
Magnetic Susceptibility ◽  
Magnetic Hyperfine Field ◽  
Metamagnetic Transition ◽  
Muffle Furnace ◽  
Temperature Dependent ◽  
X Ray ◽  
Antiferromagnetic Ordering ◽  
Divalent Europium ◽  
Polycrystalline Form ◽  
Experimental Magnetic Moment

AbstractThe plumbide EuPdPb was synthesized in polycrystalline form by reaction of the elements in a sealed niobium ampoule in a muffle furnace. The structure was refined from single-crystal X-ray diffractometer data: TiNiSi type, Pnma, a=752.4(2), b=476.0(2), c=826.8(2) pm, wR2=0.0485, 704 F2 values and 20 variables. The europium atoms are coordinated by two tilted and puckered Pd3Pb3 hexagons (280–289 pm Pd–Pb) with pronounced Eu–Pd bonding (312–339 pm). Temperature-dependent magnetic susceptibility measurements show Curie-Weiss behaviour and an experimental magnetic moment of 7.35(1) μB per Eu atom. EuPdPb orders antiferromagnetically at TN=13.8(5) K and shows a metamagnetic transition at a critical field of 15 kOe. 151Eu Mössbauer spectra confirm divalent europium (δ=–10.04(1) mm s−1) and show full magnetic hyperfine field splitting (Bhf=21.1(1) T) at 6 K.

Magnesium-rich Intermetallics RE3RuMg7 (RE=Y, Nd, Dy, Ho) – Rows of Condensed Ru@RE6/2 Octahedra in Magnesium Matrices

2013 ◽  
Vol 68 (12) ◽  
pp. 1273-1278 ◽  
Author(s):  
Marcel Kersting ◽  
Ute Ch. Rodewald ◽  
Christian Schwickert ◽  
Rainer Pöttgen
Keyword(s):  
Magnetic Susceptibility ◽  
Magnetic Moment ◽  
Small Degree ◽  
Intermetallic Phases ◽  
Metamagnetic Transition ◽  
X Ray Diffraction ◽  
Temperature Dependent ◽  
X Ray ◽  
Antiferromagnetic Ordering ◽  
Experimental Magnetic Moment

The magnesium-rich intermetallic phases RE3RuMg7 (RE=Y, Nd, Dy, Ho) have been synthesized from the elements in sealed niobium ampoules and subsequently characterized by powder X-ray diffraction. The structure of the dysprosium compound was refined on the basis of single-crystal X-ray diffractometer data: Ti6Sn5 type, P63=mmc, a=1019.1(2), c=606.76(9) pm, wR2=0.0159, 439 F2 values, 19 variables. The Mg3 site shows a small degree of Mg3=Dy mixing, leading to the composition Dy3:03RuMg6:97 for the investigated crystal. The striking structural motifs in the Dy3RuMg7 structure are rows of face-sharing Ru@Dy6 octahedra and corner-sharing Mg2@Mg8Dy4 icosahedra. The rows of octahedra form a hexagonal rod-packing, and each rod is enrolled by six rows of the condensed icosahedra. Temperature-dependent magnetic susceptibility measurements of Dy3RuMg7 show Curie-Weiss behavior with an experimental magnetic moment of 10.66(1) µB per Dy atom. Antiferromagnetic ordering is detected at TN =27.5(5) K. The 5 K isotherm shows a metamagnetic transition at a critical field of HC =40 kOe

Structure and Properties of the Stannide Eu2Au2Sn5, and its Relationship with the Family of BaAl4-Related Structures

1999 ◽  
Vol 54 (9) ◽  
pp. 1155-1164 ◽  
Author(s):  
Dirk Kußmann ◽  
Rainer Pöttgen ◽  
Ute Ch. Rodewald ◽  
Carsten Rosenhahn ◽  
Bernd D. Mosel ◽  
...  
Keyword(s):  
Hyperfine Field ◽  
Magnetic Hyperfine Field ◽  
Three Dimensional ◽  
X Ray ◽  
Antiferromagnetic Ordering ◽  
Divalent Europium ◽  
The Family ◽  
New Type ◽  
Subgroup Scheme ◽  
Experimental Magnetic Moment

The stannide Eu2Au2Sn5 was prepared by high-frequency melting of the elements in a sealed tantalum tube. The structure of Eu2Au2Sn5 was refined from single crystal X-ray data: P21/m, a = 928.6(2), b = 465.8(2), c = 1042.9(3) pm, ß = 92.28(2)°, wR2 = 0.0653, 1220 F2 values and 56 variables. The structure of Eu2Au2Sn5 is of a new type, it can be considered as an ordered defect variant of the BaAl4 type. Due to the ordered defects, the coordination number (CN) of the two crystallographically different europium sites is reduced from CN 16 to CN 14. The gold and tin atoms in Eu2Au2Sn5 form a complex three-dimensional [Au2Sn5] polyanion in which the europium atoms are embedded. Within the polyanion short Au-Sn and Sn-Sn distances are indicative of strongly bonding Au-Sn and Sn-Sn interactions. A detailed group-subgroup scheme for various ordered and defect variants of the BaAl4 family is presented. Eu2Au2Sn5 shows Curie-Weiss behavior above 50 K with an experimental magnetic moment of 7.90(5) μB/Eu, indicating divalent europium. Antiferromagnetic ordering is detected at 5.8(5) K at low fields and a metamagnetic transition occurs at a critical field of 1.4(2) T. Eu2Au2Sn5 is a metal with a specific resistivity of 150±20 μfΩcm at room temperature. The results of 151Eu and 119Sn Mössbauer spectroscopic experiments are compatible with divalent europium and show complex hyperfine field splitting with a transferred magnetic hyperfine field at the tin nuclei at low temperature.

EuTMg2 (T = Pd, Ag, Ir, Pt, Au), EuTCd2 (T = Pd, Pt, Au) and CaRhMg2 – intermetallic compounds with orthorhombically distorted tetrahedral magnesium (cadmium) substructures

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Steffen Klenner ◽  
Maximilian Kai Reimann ◽  
Rainer Pöttgen
Keyword(s):  
Valence Electron ◽  
Intermetallic Phases ◽  
Stacking Sequence ◽  
X Ray Diffraction ◽  
Temperature Dependent ◽  
Space Group ◽  
X Ray ◽  
Type Space ◽  
Antiferromagnetic Ordering ◽  
Divalent Europium

Abstract The magnesium- and cadmium-rich intermetallic phases EuTMg2 (T = Rh, Pd, Ag, Ir, Pt, Au), EuTCd2 (T = Pd, Pt, Au) and CaRhMg2 were synthesized from the elements in sealed niobium or tantalum ampoules and with heat treatments in muffle or induction furnaces. The samples were characterized by powder X-ray diffraction and the structures were refined from single crystal X-ray diffractometer data. EuTMg2 (T = Pd, Ag, Pt, Au) and EuTCd2 (T = Pd, Pt, Au) crystallize with the MgCuAl2 type, space group Cmcm, while EuRhMg2, EuIrMg2 and CaRhMg2 adopt the YSiPd2 type, space group Pnma. The striking crystal chemical motif of both series of compounds are networks of puckered Mg(Cd) hexagons in ABAB stacking sequence that derive from the aristotype AlB2; however, with different tiling. Temperature dependent magnetic susceptibility and 151Eu Mössbauer spectroscopic measurements indicate stable divalent europium. Antiferromagnetic ordering sets in at 20.2 (EuIrMg2), 22.3 (EuPdMg2), 21.3 (EuAgMg2), 10.9 (EuPdCd2) and 15.5 K (EuPtCd2), respectively. The stable antiferromagnetic ground states are substantiated by metamagnetic transitions. The 151Eu isomer shifts show a linear correlation with the valence electron count for the whole series of EuTMg2, EuTCd2, EuTIn2 and EuTSn2 phases.

The Stannides EuPd2Sn2, EuPt2Sn2, EuAu2Sn2, and Eu5.4Sn5.6 – Structure and Magnetic Properties

2014 ◽  
Vol 69 (7) ◽  
pp. 775-785 ◽  
Author(s):  
Christian Schwickert ◽  
Florian Winter ◽  
Rainer Pöttgen
Keyword(s):  
Magnetic Hyperfine Field ◽  
Three Dimensional ◽  
X Ray Diffraction ◽  
Temperature Dependent ◽  
Space Group ◽  
X Ray ◽  
Antiferromagnetic Ordering ◽  
Divalent Europium ◽  
Sample Chamber ◽  
Tin Coordination

The europium stannides EuT2Sn2 (T = Pd, Pt, Au) and Eu3Ag5.4Sn5.6 were synthesized by highfrequency melting of the elements in sealed niobium ampoules in a water-cooled sample chamber. All samples were characterized by powder X-ray diffraction. The EuT2Sn2 (T = Pd, Pt, Au) stannides crystallize with the CaBe2Ge2-type structure, space group P4/nmm. The structure of EuPd2Sn2 was refined from single-crystal X-ray diffractometer data: a = 462.44(8), c = 1045.8(3) pm, wR = 0.0402, 237 F2 values and 15 refined variables. The palladium and tin atoms build up a threedimensional [Pd2Sn2] polyanionic network, exclusively with Pd-Sn interactions (261 - 269 pm). The Pd1 and Pd2 atoms have square-pyramidal and tetrahedral tin coordination, respectively. The europium atoms fill large voids within the network. They are coordinated to eight palladium and eight tin atoms. Temperature-dependent magnetic susceptibility studies confirm a stable divalent ground state of the europium atoms. The compounds become ordered antiferromagnetically below 6.3 (EuPd2Sn2), 6.1 (EuPt2Sn2) and 7.7 K (EuAu2Sn2). Eu3Ag5.4Sn5.6 adopts a partially ordered variant of the La3Al11 type, space group Immm, a = 471.33(8), b = 1382.5(4), c = 1032.4(2) pm, wR = 0.0449, 692 F2 values, 30 variables. The three-dimensional [Ag5.4Sn5.6] network shows one silver and one tin site besides two sites with substantial Ag/Sn mixing. The two crystallographically independent europium atoms fill larger and smaller cavities within the [Ag5.4Sn5.6] network. Eu3Ag5.4Sn5.6 also shows divalent europium and antiferromagnetic ordering at TN = 6:9 K. A 151Eu Mössbauer spectrum of Eu3Ag5.4Sn5.6 at 5.2 K shows an isomer shift of δ = −10.61 mms−1, typical for Eu(II) compounds, and a magnetic hyperfine field splitting of BHf = 5.9 T. 119Sn Mössbauer spectra of the four stannides show isomer shifts in the range of δ = 1.78 - 2.20 mms−1, usually observed for tin in intermetallic compounds.

Ternary Antimonides RE4T7Sb6 (RE=Gd–Lu; T =Ru, Rh) with Cubic U4Re7Si6-type Structure

2013 ◽  
Vol 68 (9) ◽  
pp. 971-978 ◽  
Author(s):  
Inga Schellenberg ◽  
Ute Ch. Rodewald ◽  
Christian Schwickert ◽  
Matthias Eul ◽  
Rainer Pöttgen
Keyword(s):  
Magnetic Susceptibility ◽  
Single Crystal ◽  
Magnetic Moment ◽  
Induction Furnace ◽  
X Ray Diffraction ◽  
Temperature Dependent ◽  
X Ray ◽  
Antiferromagnetic Ordering ◽  
Arc Melting ◽  
Intermediate Valent

The ternary antimonides RE4T7Sb6 (RE=Gd-Lu; T =Ru, Rh) have been synthesized from the elements by arc-melting and subsequent annealing in an induction furnace. The samples have been characterized by powder X-ray diffraction. Four structures were refined on the basis of single-crystal X-ray diffractometer data: U4Re7Si6 type, space group Im3m with a=862.9(2) pm, wR2=0.0296, 163 F2 values for Er4Ru7Sb6; a=864.1(1) pm, wR2=0.1423, 153 F2 values for Yb4Ru7Sb6; a=872.0(2) pm, wR2=0.0427, 172 F2 values for Tb4Rh7Sb6; and a=868.0(2) pm, wR2=0.0529, 154 F2 values for Er4Rh7Sb6, with 10 variables per refinement. The structures have T1@Sb6 octahedra and slightly distorted RE@T26Sb6 cuboctahedra as building units. The distorted cuboctahedra are condensed via all trapezoidal faces, and this network leaves octahedral voids for the T1 atoms. The ruthenium-based series of compounds was studied by temperature-dependent magnetic susceptibility measurements. Lu4Ru7Sb6 is Pauli-paramagnetic. The antimonides RE4Ru7Sb6 with RE=Dy, Ho, Er, and Tm show Curie-Weiss paramagnetism. Antiferromagnetic ordering occurs at 10.0(5), 5.1(5) and 4.0(5) K for Dy4Ru7Sb6, Ho4Ru7Sb6 and Er4Ru7Sb6, respectively, while Tm4Ru7Sb6 remains paramagnetic. Yb4Ru7Sb6 is an intermediate-valent compound with a reduced magnetic moment of 3.71(1) μB per Yb as compared to 4.54 μB for a free Yb3+ ion

Nickel-deficient Stannides Eu2Ni2–xSn5 – Structure, Magnetic Properties, and Mössbauer Spectroscopic Characterization

2009 ◽  
Vol 64 (10) ◽  
pp. 1107-1114 ◽  
Author(s):  
Thomas Harmening ◽  
Matthias Eul ◽  
Rainer Pöttgen
Keyword(s):  
Solid Solution ◽  
Magnetic Properties ◽  
Powder Diffraction ◽  
Spectroscopic Characterization ◽  
Structure Type ◽  
Induction Melting ◽  
X Ray ◽  
Antiferromagnetic Ordering ◽  
Divalent Europium ◽  
Experimental Magnetic Moment

New nickel-deficient stannides Eu2Ni2−xSn5 were synthesized by induction melting of the elements in sealed tantalum tubes. The solid solution was studied by X-ray powder diffraction and two crystal structures were refined on the basis of X-ray diffractometer data: Cmcm, a = 466.03(4), b = 3843.1(8), c = 462.92(9) pm, wR2 = 0.0469, 692 F2 values, 39 variables for Eu2Ni1.49(1)Sn5 and a = 466.11(9), b = 3820.1(8), c = 462.51(9) pm, wR2 = 0.0358, 695 F2 values, 39 variables for Eu2Ni1.35(1)Sn5. This new structure type can be considered as an intergrowth structure of CaBe2Ge2- and CrB-related slabs. The striking structural motifs are nickel-centered square pyramids which are condensed via common corners and edges. The layers of condensed NiSn5 units are separated by the europium atoms. The Ni1 sites within the CaBe2Ge2 slabs show significant defects which leads to split positions for one tin site. Eu2Ni1.50Sn5 shows Curie-Weiss behavior and an experimental magnetic moment of 7.74(1) μB / Eu atom, indicating stable divalent europium, as is also evident from 151Eu Mössbauer spectra. Antiferromagnetic ordering is detected at 3.5 K.

Dimorphic EuCu5Cd

2012 ◽  
Vol 67 (10) ◽  
pp. 1107-1114 ◽  
Author(s):  
Frank Tappe ◽  
Christian Schwickert ◽  
Rainer Pöttgen
Keyword(s):  
Magnetic Susceptibility ◽  
Small Degree ◽  
Muffle Furnace ◽  
Temperature Dependent ◽  
X Ray ◽  
Coordination Numbers ◽  
Dsc Measurements ◽  
Divalent Europium ◽  
Experimental Magnetic Moment ◽  
High Coordination

Two modifications of EuCu5Cd were synthesized from the elements in sealed tantalum ampoules.The high-temperature (HT) modification was obtained from an induction-melted sample that was finally annealed at 873 K, while the low-temperature (LT) phase is formed in a muffle furnace by annealing a pre-melted sample at 673 K. DSC measurements gave a transition temperature of 823±2 K. Both structures were refined on the basis of single-crystal X-ray diffractometer data: R3̄m, a = 511:58(7), c = 3059:6(6) pm, wR2 = 0.0289, 316 F2 values, 22 variables for HTEuCu4 :85(1)Cd1:15(1) and Pnma, a = 2545:6(5), b = 511:60(1), c = 1060:3(2) pm, wR2 = 0.0386, 2044 F2 values, 121 variables for LT-EuCu4:92(1)Cd1:08(1). A small degree of Cu/Cd mixing was observed for three sites. Both structures adopt new types. The europium atoms have high coordination numbers of 18, 19 and 20 in LT- and 18 and 20 in HT- EuCu5Cd. These three types of polyhedra are the basic building units also in the closely related structures of CeCu6, CeCu5Au, CeCu4:38In1:62, and CeNi5Sn, a family of stacking variants. Temperature-dependent magnetic susceptibility measurements of a HT- EuCu5Cd sample showed an experimental magnetic moment of 7.56(1) μB per Eu atom in the paramagnetic regime, compatible with divalent europium. HT- EuCu5Cd orders antiferromagnetically at 17.7(5) K.

Intermetallic Cadmium Compounds M5T2Cd (M = Ca, Yb, Eu; T = Cu, Ag, Au) with Mo5B2Si-type Structure

2011 ◽  
Vol 66 (12) ◽  
pp. 1219-1224
Author(s):  
Frank Tappe ◽  
Christian Schwickert ◽  
Matthias Eul ◽  
Rainer Pöttgen
Keyword(s):  
Magnetic Moments ◽  
Small Degree ◽  
X Ray Diffraction ◽  
Temperature Dependent ◽  
X Ray ◽  
Antiferromagnetic Ordering ◽  
Pauli Paramagnetism ◽  
Slab Temperature ◽  
Experimental Magnetic Moment ◽  
The Eu

The intermetallic compounds M5T2Cd (M = Ca, Yb, Eu; T = Cu, Ag, Au) and Yb5Cu2Zn were synthesized by melting the elements in sealed tantalum tubes followed by annealing at 923 K. All phases were characterized on the basis of powder and single-crystal X-ray diffraction data: Mo5B2Si type, I4/mcm, Z = 4, a = 828.7(1), c = 1528.1(3) pm, wR2 = 0.030, 440 F2 values, 16 variables for Eu5Cu2Cd, a = 788.2(1), c = 1459.3(5) pm, wR2 = 0.053, 378 F2 values, 16 variables for Yb5Cu2Cd, and a = 797.2(1), c = 1438.8(3) pm, wR2 = 0.036, 386 F2 values, 17 variables for Yb5Au2.19Cd0.81, which shows a small degree of Au / Cd mixing. The M5T2Cd structures are intergrowth variants of slightly distorted CuAl2- and U3Si2-related slabs. Striking coordination motifs (exemplary for Eu5Cu2Cd) are square antiprisms of the Eu atoms around Cd, Eu8 square prisms around Eu, and trigonal Eu6 prisms around Cu within the AlB2-related slab. Temperature-dependent magnetic susceptibility measurements showed Pauli paramagnetism for Yb5Cu2Zn, indicating purely divalent ytterbium. Eu5Au2Cd exhibits Curie-Weiss behavior above 100 K with an experimental magnetic moment of 8.14 μB per Eu atom and a Weiss constant of 56 K. Antiferromagnetic ordering of the EuII magnetic moments is evident at 36 K, and a metamagnetic transition is observed at 25 K and 13 kOe.

The stannides Ca1.692Pt2Sn3.308, SrPtSn2 and EuAuSn2

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Steffen Klenner ◽  
Maximilian Kai Reimann ◽  
Stefan Seidel ◽  
Rainer Pöttgen
Keyword(s):  
Magnetic Hyperfine Field ◽  
Three Dimensional ◽  
Magnetic Ordering ◽  
Temperature Dependent ◽  
Crucible Material ◽  
Phase Purity ◽  
X Ray ◽  
Calcium Compound ◽  
Experimental Magnetic Moment ◽  
Tin Coordination

Abstract Polycrystalline samples of the stannides Ca1.692Pt2Sn3.308, SrPtSn2 and EuAuSn2 were synthesized directly from the elements, using sealed tantalum ampoules as crucible material. The reactions were performed in muffle or induction furnaces. The phase purity of the samples was studied by X-ray powder diffraction (Guinier technique). The structures of Ca1.692Pt2Sn3.308 and SrPtSn2 were refined from single-crystal X-ray diffractometer data: NdRh2Sn4 type, Pnma, a = 1887.22(13), b = 441.22(3), c = 742.89(4) pm, wR = 0.0626, 1325 F 2 values, 45 variables for Ca1.692(8) Pt2Sn3.308(8) and CeNiSi2 type, Cmcm, a = 462.59(5), b = 1932.8(2), c = 458.00(5) pm, wR = 0.0549, 481 F 2 values, 18 variables for SrPtSn2. The calcium compound shows a homogeneity range Ca1+x Pt2Sn4−x with substantial Sn4/Ca2 mixing on one of the 4c Wyckoff positions. The [PtSn2] network is characterized by Pt–Sn (269–281 pm) and Sn–Sn (306–336 pm) bonding interactions. SrPtSn2 contains two different tin substructures: (i) Sn1–Sn1 zig-zag chains (282 pm) and (ii) orthorhombically distorted Sn2 squares (326 pm) with stronger and weaker Sn–Sn bonding. Together, the platinum and tin atoms build up a three-dimensional [PtSn2] network in which the platinum atoms have a distorted square-pyramidal tin coordination with Pt–Sn distances ranging from 261–270 pm. EuAuSn2 also crystallizes with the CeNiSi2-type structure with the lattice parameters a = 453.9(1), b = 2018.9(5) and c = 456.8(1) pm. Temperature dependent magnetic susceptibility studies indicate europium(II) with an experimental magnetic moment of 8.28(2) µB per Eu atom. EuAuSn2 is ordered antiferromagnetically at T N  = 14.8(2) K. 151Eu Mössbauer spectra confirm the oxidation state +2 for europium (isomer shift δ = −11.17(2) mm s−1) and the magnetic ordering at low temperature (21.8 T magnetic hyperfine field at 6 K).

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