Discovery and Characterization of Antiferromagnetic UFe5As3

This work presents a study on a new uranium iron arsenide UFe5As3. By implementing Bi-flux synthesis, we were able to grow mm-sized single crystals of this compound, which show twinning. UFe5As3 is one of only two known uranium iron arsenides. It adopts a monoclinic, UCr5P3-type crystal structure (space group P21/m, Pearson symbol mP18, a = 7.050(2) Å, b = 3.8582(9) Å, c = 9.634(1) Å, β = 100.25(1)°). The magnetic susceptibility of UFe5As3 indicates it to be an antiferromagnet with TN = 47 K and μeff = 4.94 μB per formula unit, signaling that both U and Fe are likely magnetic in this material. The material appears to be anisotropic, with a small (likely ferromagnetic) spin reorientation transition around T = 29 K. The Sommerfeld coefficient γ0 = 135 mJ mol-1 K-2 suggests enhanced effective electron mass in UFe5As3, while electrical resistivity indicates metallic, Kondo-like behavior.

Non-centrosymmetric superconductor Th[Formula: see text]Be[Formula: see text]Pt[Formula: see text] and heavy-fermion U[Formula: see text]Be[Formula: see text]Pt[Formula: see text] cage compounds

Unconventional superconductivity in non-centrosymmetric superconductors has attracted a considerable amount of attention. While several lanthanide-based materials have been reported previously, the number of actinide-based systems remains small. In this work, we present the discovery of a novel cubic complex non-centrosymmetric superconductor [Formula: see text] ([Formula: see text] space group). This intermetallic cage compound displays superconductivity below [Formula: see text] K, as evidenced by specific heat and resistivity data. [Formula: see text] is a type-II superconductor, which has an upper critical field [Formula: see text] T and a moderate Sommerfeld coefficient [Formula: see text] mJ [Formula: see text] [Formula: see text]. A non-zero density of states at the Fermi level is evident from metallic behavior in the normal state, as well as from electronic band structure calculations. The isostructural [Formula: see text] compound is a paramagnet with a moderately enhanced electronic mass, as indicated by the electronic specific heat coefficient [Formula: see text] mJ [Formula: see text] [Formula: see text] and Kadowaki-Woods ratio [Formula: see text] [Formula: see text] [Formula: see text] cm [Formula: see text] [Formula: see text] (mJ)[Formula: see text]. Both [Formula: see text] and [Formula: see text] are crystallographically complex, each hosting 212 atoms per unit cell.

The crystal growth and properties of novel magnetic double molybdate RbFe5(MoO4)7 with mixed Fe3+/Fe2+ states and 1D negative thermal expansion

Single crystals of new composition RbFe₅(MoO₄)₇ were successfully grown by the flux method, and their crystal structure was determined using the X-ray single-crystal diffraction technique.

New Ternary Phosphide La7Pd17P12: Preparation and Crystal Structure

The title compound was prepared from elements by sintering in the temperature region between 1073 and 1473 K. The monoclinic structure of La7Pd17P12 was solved and refined from X-ray single crystal data: space group C2/m, a = 24.519(1), b = 4.0859(5), c = 13.6106(8)Å , β = 112.129(3)°, Z = 2, RF = 0.025 for 1065 unique of 4877 measured reflections and 112 refined parameters. Main structural motif of the new phosphide are condensed blocks of trigonal prisms around phosphorus atoms connected to infinite chains via lanthanum atoms. The structural features of La7Pd17P12 are discussed in comparison with some representatives of a large family of structures with metal / non-metal ratio close to 2 : 1.

Re-investigation of the crystal structure of trieuropium octagallide, Eu3-xGa8+3x (x = 0.12)

Eu2.88Ga8.36, orthorhombic, Immm (no. 71), a = 4.4105(3) Å, b = 4.3732(2) Å, c = 25.852(1) Å, V = 498.6 Å3, Z = 2, Rgt(F) = 0.025, wRref(F) = 0.062, T = 295 K.

Crystal structure of dieuropium trigallium iridium, Eu2Ga3Ir

Eu2Ga3Ir, hexagonal, P63/mmc (no. 194), a = 5.6785(2) Å, c = 8.6911(5) Å, V = 242.7 Å3, Z = 2, Rgt(F) = 0.032, wRref(F) = 0.028, T = 293 K.

Crystal structure of rubidium scandium (monophosphate-hydrogenmonoborate- monophosphate), RbSc[BP2O8(OH)]

BHO9P2RbSc, triclinic, P1̅ (no. 2), a = 5.3296(2) Å, b = 8.3919(8) Å, c = 8.4319(5) Å, α = 87.27(1)°, β = 80.124(6)°, γ = 86.60(1)°, V = 370.6 Å3, Z = 2, Rgt(F) = 0.024, wRref(F2) = 0.066, T = 293 K.

Crystal structure of potassium scandium (monophosphate-hydrogenmonoborate- monophosphate), KSc[BP2O8(OH)]

BHKO9P2Sc, triclinic, P1̅ (no. 2), a = 5.2696(2) Å, b = 8.2739(8) Å, c = 8.3890(5) Å, α = 88.22(1)°, β = 79.701(6)°, γ = 86.67(1)°, V = 359.2 Å3, Z = 2, Rgt(F) = 0.032, wRref(F2) = 0.075, T = 295 K.

Crystal structure of cobalt aluminum silicide, Co10+xAl23Si9–2x (x = 0.14), the φ phase in the Co-Al-Si system

Al23Co10.14Si8.72, orthorhombic, Pnma (no. 62), a = 13.852(3) Å, b = 23.055(5) Å, c = 7.340(2) Å, V = 2344.1 Å3, Z = 4, Rgt(F) = 0.035, wRref(F2) = 0.081, T = 293 K.

Crystal structures of (barium, europium) platinum trigermanium, Ba1-xEuxPtGe3 (x = 0, 0.27, 1)

BaGe3Pt, tetragonal, I4mm (no. 107), a = 4.5636(2) Å, c = 10.2341(6) Å, V = 213.1 Å3, Z = 2, Rgt(F) = 0.030, wRref(F2) = 0.074, T = 293 K.

Ba0.73Eu0.27Ge3Pt, tetragonal, I4mm (no. 107), a = 4.5432(1) Å, c = 10.1763(2) Å, V = 210.0 Å3, Z = 2, Rgt(F) = 0.025, wRref(F2) = 0.061, T = 293 K.

EuGe3Pt, tetragonal, I4mm (no. 107), a = 4.4633(1) Å, c = 10.0625(4) Å, V = 200.5 Å3, Z = 2, Rgt(F) = 0.018, wRref(F2) = 0.035, T = 293 K.

Crystal structures of cobalt aluminum silicide, Co19+xAl43+ySi12-y (x = -0.14, y = 0.14; x = 0.49, y = -0.49), the ϒ phase in the Co-Al-Si system

Al43.14Co18.86Si11.86, monoclinic, C12/c1 (no. 15), a = 20.010(2) Å, b = 19.1498(7) Å, c = 12.8227(8) Å, β = 123.56(1)°, V = 4094.6 Å3, Z = 4, Rgt(F) = 0.035, wRref(F2) = 0.079, T = 293 K.

Al42.51Co19.49Si12.49, monoclinic, C12/c1 (no. 15), a = 20.025(2) Å, b = 19.173(2) Å, c = 12.835(1) Å, β = 123.63(1)°, V = 4103.2 Å3, Z = 4, Rgt(F) = 0.044, wRref(F2) = 0.108, T = 293 K.

Refinement of the crystal structure of diniobium trisoxydisulfate hydrate, Nb2O3(SO4)2 · 0.25H2O

H0.5Nb2O11.25S2, trigonal, R3̅ (no. 148), a = 10.378(2) Å, c = 26.540(5) Å, V = 2475.7 Å3, Z = 24, Rgt(F) = 0.031, wRref(F2) = 0.072, T = 295 K.