A5072956024- Rare-earth and actinide compounds
- Inorganic Chemistry and Materials
- Iron-based superconductors research
- Crystallization and Solubility Studies
- Intermetallics and Advanced Alloy Properties
- X-ray Diffraction in Crystallography
- Quasicrystal Structures and Properties
- Luminescence Properties of Advanced Materials
- Inorganic Fluorides and Related Compounds
- Metallurgical and Alloy Processes
- Magnetic and transport properties of perovskites and related materials
- Advanced ceramic materials synthesis
- Muon and positron interactions and applications
- Nuclear Materials and Properties
- Catalytic Processes in Materials Science
- Boron and Carbon Nanomaterials Research
Saarland University
2022-2025
Laves phases exhibit a plethora of different structures and multitude physical properties. Investigations in the ternary system Hf-V-Al led to discovery numerous members solid solution Hf(V
The binary alkaline-earth aluminides AEAl2 (AE = Ca and Sr) AEAl4 Ca-Ba) have been synthesized from the elements investigated via powder X-ray diffraction experiments. CaAl2 adopts cubic MgCu2-type structure (Fd3̅m), while SrAl2 crystallizes in orthorhombic KHg2-type (Imma). LT-CaAl4 with monoclinic CaGa4-type (C2/m), HT-CaAl4, SrAl4, BaAl4 adopt tetragonal BaAl4-type (I4/mmm). close structural relation of two CaAl4 polymorphs was established using a group-subgroup Bärnighausen formalism. In...
Abstract In most intermetallic europium compounds, the Eu atoms exhibit a divalent oxidation state with high effective magnetic moment since 2+ is isoelectronic Gd 3+ . Trivalent in contrast, are extremely scarce and under 20 examples known to literature. This mini-review summarizes binary ternary along their crystal-chemical peculiarities as well 151 Mössbauer spectroscopic behavior. Additionally, compounds that valence phase transitions summarized.
Abstract Large lath-shaped single crystals of SrAl 8 Rh 2 were grown during attempts to synthesize 4 in analogy Ir . Single crystal experiments determined the structure be isostructural CeAl Fe type crystallizing orthorhombic system with space group Pbam ( a = 1269.74(4), b 1475.43(5), c 412.55(1) pm, w R 0.0398, 2088 F values and 70 variables). is first reported compound ternary Sr–Al–Rh. No mixing on any atomic position was observed. Attempts bulk led multiphase mixture according powder...
The REAl 2 series was characterized by solid-state NMR and Raman experiments. spectroscopic data correlated to the XRD measurements DFT calculations, gaining an insight into bonding, charge distribution strain.
Following recent investigation in the ternary system Sr-Al-Pt led to discovery of SrAl
Several ternary rare-earth metals containing titanium aluminum intermetallics in the RE2TiAl3 series (RE = Y, Gd–Lu) have been synthesized from elements using arc-melting techniques. All compounds crystallize trigonal crystal system with rhombohedral space group R3m (Z 3) and lattice parameters ranging between a 582–570 c 1353–1358 pm. They adopt Mg2Ni3Si-type structure, which is an ordered superstructure of cubic Laves phase MgCu2 has observed for Al first time. Tetrahedral [TiAl3] entities...
Ternary sulfides are usually synthesized from the binary sulfidic precursors at elevated temperatures using prolonged reaction times and sometimes H2S atmosphere to remove residual oxygen. The direct synthesis elements is hampered by highly exothermic vaporizing sulfur. One way suppress this use a prereacted metallic precursor. In work, well-defined crystalline intermetallic compounds CaAl2, SrAl2, EuAl2 have been reacted with elemental sulfur in less than 24 h 1173 K achieving phase pure...
Abstract During attempts to synthesize new platinides in the ternary system Sr–Al–Pt, single crystals of SrAl 5 Pt 3 and Sr 2 Al 16 9 were obtained from a reaction elements with nominal composition 4 13 . Both orthorhombic structures refined based on crystal x-ray diffraction data (SrAl : Pnma , Wyckoff sequence c = 2065.04(7), b 413.74(1), 738.98(3) pm, wR 0.0310, 867 F values, 56 variables; Immm l j ihga 416.69(2), 1193.53(6), 1832.38(9) 0.0517, 671 49 variables); full atomic ordering was...
The oxidation of the intermetallic compound CaAl 2 does not lead, as one might expect, to O 4 , but instead, Ca 12 Al 14 33 is formed. This reacts in subsequent annealing steps with also formed 3 expected phase.
Abstract The solid solutions Eu 2 Al 15 (Pt 1− x T ) 6 with = Pd, Ir, Au and 1/6 were prepared by arc-melting the stoichiometric mixture of elements, subsequent annealing. For 1/6, all three adopt same structure type as Pt according to powder X-ray diffraction data. Since platinide exhibits a (3 + 1)D modulated (approximant in space group P 12 1 / m 1), only averaged hexagonal unit cell ( 3 mmc , Sc 0.6 Fe Si 4.9 type) was refined Rietveld method. Scanning electron microscopy combination...
Abstract Single crystals of CaAl 2 Pt , Ca Al 3 and AlPt were initially observed in an attempt to synthesize 4 . Their structures determined using single‐crystal X‐ray diffraction experiments. While nominal (CaBe Ge type, P 4/ nmm a =426.79(2), c =988.79(6) pm, w R =0.0679, 246 F values 18 variables) (Mg Cu Si 6 / mmc =561.46(5), =876.94(8) =0.0664, 214 13 exhibit Al/Pt mixing, for (Ca Ir C 2/ =981.03(2) b =573.74(1), =772.95(2) β =101.862(1)° =0.0307, 2246 25 no mixing was observed....
Abstract Within the series of equiatomic RE AlRh compounds, representatives with = Y, La–Nd, Gd, Ho, Tm and Yb have been synthesized. The members Sm, Tb, Dy, Er Lu, however, had not yet reported. They now synthesized structurally as well magnetically NMR-spectroscopically characterized. All crystallize isostructurally in orthorhombic TiNiSi type, similar to most known analogues. evolution their unit cell volumes exhibits expected decrease due lanthanide contraction. While LuAlRh shows...
Laves phases are an interesting field of research when it comes to structural chemistry and physical properties. Investigations the ternary system Zr–V–Al showed, in contrast Hf–V–Al, that no superstructures can be observed within solid solution Zr(V1–xAlx)2. High values x form aluminum rich adopt hexagonal MgZn2 type structure while low lead vanadium cubic MgCu2 type. All samples were investigated by powder X‐ray diffraction experiments. Single crystal studies indicated superstructure...
Abstract Investigations in the ternary system Eu–Al–Pt led to discovery of Eu 4 Al 13 Pt 9 , a new representative exhibiting coloring variant Ho Ir Ge type structure. The orthorhombic structure was refined based on single crystal X-ray diffraction data ( Pmmn Wyckoff sequence e b 3 5 = 415.38(1), 1149.73(2), c 1994.73(5) pm, wR 2 0.0622, 1901 F values, 88 variables) and full atomic ordering observed for all atoms. features complex [Al ] δ – network with atoms occupying hexagonal prismatic...
Abstract Three new iridium aluminum intermetallics CaAl 4 Ir 2 , SrAl and EuAl were synthesized from the elements using silica or tantalum ampoules. They crystallize in tetragonal crystal system with space group P 4/ ncc lattice parameters of a = 782.20(1) c 779.14(2) pm for 797.62(1) 772.75(2) finally 791.78(5) 773.31(5) . All compounds isostructurally adopt structure type that can be derived KAu In structure. To compare structures crystallographic point view, group–subgroup relation...