Nb₄Pd_0.5ZSb₂ (Z = Cr, Fe, Co, Ni, Si):  The First Ordered Quaternary Variants of the W₅Si₃-Type Structure

Abstract

A family of quaternary (or pseudoquaternary) antimonides Nb4Pd0.5ZSb2 (Z = Cr, Fe, Co, Ni, Si) containing up to three transition metals in an ordered arrangement has been prepared by reactions of the elements. These antimonides are isostructural, crystallizing as substitutional variants of the W5Si3-type structure (tetragonal, space group -I4/mcm, Z = 4) with unit cell parameters a = 10.4407(3) A and c = 5.0020(2) A for Nb4Pd0.5Cr0.28(3)Si0.72Sb2, a = 10.4825(6) A and c = 4.9543(3) A for Nb4Pd0.5FeSb2, a = 10.4603(5) A and c = 4.9457(3) A for Nb4Pd0.5CoSb2, a = 10.4332(7) A and c = 4.9649(3) A for Nb4Pd0.5Ni0.78(1)Sb2, and a = 10.3895(10) A and c = 4.9634(4) A for Nb4Pd0.5SiSb2. They are distinguished by the filling of interstitial Z atoms into the centers of Nb8 square antiprismatic clusters that are linked by PdSb4 tetrahedra. The Nb8 square antiprisms share opposite square faces to form one-dimensional chains along the c axis so that Z-Z bonding distances of approximately 2.5 A result. Extended Hückel band structure calculations were carried out to interpret the homo- and heteroatomic metal-metal interactions in the structure. The resistivity of one member, Nb4Pd0.5SiSb2, was measured, indicating metallic behavior.

Quality of Life and Functioning of People With Mental Disorders Who Underwent Deinstitutionalization Using Assisted Living Facilities: A Cross-Sectional Study

“…In addition to the mental disorder itself, which contributes to interpersonal difficulties, the isolation caused by a long hospitalization period reinforces social impairment and the need for reintegration, that could contribute to an improvement in QoL and functioning. These factors can explain, in part, the low score obtained in the Physical health and Psychological domains, since these domains cover issues about body health, energy, feelings, capacity perception, body perception and self-esteem ( The WHOQOL Group, 1996 ; Pedroso et al, 2010 ).…”

“…WHOQOL-BREF ( The WHOQOL Group, 1996 ) is a QoL questionnaire developed by the World Health Organization, composed of 24 items clustered into four domains: Physical health, Psychological, Social relationships, and Environment; and two items referring to the Self-evaluation of the QoL, totaling 26 items ( Fleck et al, 2000 ; Pedroso et al, 2010 ). It was developed by specialists from different cultures as a generic intercultural instrument that could be used by different professionals ( Angelim et al, 2015 ).…”

Zr5Sb3−xRux, a new superconductor in the W5Si3 structure type

“…15 The ternary compounds Zr 5 Sb 3Àx M x (M = Fe, Co and Ni) and the quaternary compounds Nb 4 Pd 0.5 Sb 2 M x (M = Cr, Fe, Co, Ni and Si) have been synthesized and characterized as having this structure type. 16,17 Motivated by our recent discovery of superconductivity in Hf 5 Sb 2.5 Ru 0.5 , we here examine the effect of moving from a 5d-based to a 4d-based compound. The new material Zr 5 Sb 2.4 Ru 0.6 , is superconducting with a T c of 5 K.…”

Remarkable Metal-Rich Ternary Chalcogenides Sc14M3Te8 (M = Ru, Os)

“…These chains are further interconnected by shared TM 4/2 tetrahedra. Other ternary variants exhibit different interconnections between the former chains, as in (Bi 4 Ru)X 2 (X ) Br, I), 6 (Ti 4 M)Br 2 (M ) Cr-Ni), 7 (V 4 Si)Sb 2 , 8 (Nb 4 M)Pb 0.5 Sb 2 (M ) Cr, Fe-Ni, Si), 4 (Ta 4 M)Te 4 (M ) Cr, Fe-Ni, Al, Si), 9 and (R 4 Os)Br 4 (R ) Y, Er). 10 We have now discovered a novel and quite different structure type that contains chains in which pairs of square antiprismatic scandium alternate with scandium cubes, each cluster being centered by a ruthenium or osmium atom.…”

“…Early transition-metal-rich halides, chalcogenides, and pnictides , have been widely studied. Relative to the present compounds, numerous phases exhibit the well-known W 5 Si 3 -type tetragonal structure 1 ∞ [(W 8/2 Si)(WSi 4/2 )], which in part contains infinite chains of square antiprismatic transition metal T centered by a later element M, generally a transition metal or main group element (Si, etc.).…”