Metal-metal bonding in reduced scandium halides. Synthesis and characterization of heptascandium decachloride (Sc7Cl10). A novel metal-chain structure

Kenneth R Poeppelmeier, John D. Corbett

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Abstract

The reaction of scandium metal with scandium trihalide in a sealed tantalum container under a temperature gradient 880-900 °C results in transport of monocrystals of heptascandium decachloride (ScCl1.43) to the hot zone. The compound crystallizes in the monoclinic space group C2/m with a = 18.620 (7) Å, b = 3.5366 (7) Å, c = 12.250 (5) Å, β = 91.98 (4)°, and Z = 2. Full-matrix least-squares refinement of all atoms with anisotropic thermal parameters gave final residuals R = 0.059 and Rw = 0.072 for 705 independent reflections with 2θ ≤ 50° and I > 3σ(I). The unique feature of the structure is the presence of infinite chains composed of two parallel chains of scandium octahedra which share a common edge. Chlorine atoms cap all outward facing metal triangles and also bridge (a) to and (b) between isolated Sc(III) metal ions, giving the connectivity description (ScClb4/2Cla2/3) (Sc6Cl6Cla 4/3) where the fractional atoms Cla and Clb provide the bridging functions. The structure is thus intermediate between the single chains of octahedra found in GdCl1.5 and the infinite two-dimensional sheets of edge-shared octahedra in ScCl. Magnetic susceptibility measurements between 79 and 297 K (Faraday method) indicate a Curie-Weiss behavior above ∼120 K (μ = 1.04 μB, θ = -498 K) with evidence of magnetic ordering at T <79 K. This and a sharp EPR signal at room temperature (g = 1.97) are interpreted in terms of localized, weakly interacting (at 297 K) d1 configurations for two (of six) particular scandium atoms in the chain. The occurrence of strongly bonded and well-separated metal chains and the physical properties resulting therefrom suggest the phase can be described as a crystalline analogue of a metal fiber composite.

Original languageEnglish
Pages (from-to)1107-1111
Number of pages5
JournalInorganic Chemistry
Volume16
Issue number5
Publication statusPublished - 1977

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Scandium
metal-metal bonding
scandium
halides
Metals
Atoms
synthesis
metals
atoms
Tantalum
metal fibers
Chlorine
Magnetic susceptibility
Thermal gradients
fiber composites
Metal ions
Containers
Paramagnetic resonance
Magnetization
tantalum

ASJC Scopus subject areas

  • Inorganic Chemistry

Cite this

@article{76dfc6382748498fbc868a224dbb981d,
title = "Metal-metal bonding in reduced scandium halides. Synthesis and characterization of heptascandium decachloride (Sc7Cl10). A novel metal-chain structure",
abstract = "The reaction of scandium metal with scandium trihalide in a sealed tantalum container under a temperature gradient 880-900 °C results in transport of monocrystals of heptascandium decachloride (ScCl1.43) to the hot zone. The compound crystallizes in the monoclinic space group C2/m with a = 18.620 (7) {\AA}, b = 3.5366 (7) {\AA}, c = 12.250 (5) {\AA}, β = 91.98 (4)°, and Z = 2. Full-matrix least-squares refinement of all atoms with anisotropic thermal parameters gave final residuals R = 0.059 and Rw = 0.072 for 705 independent reflections with 2θ ≤ 50° and I > 3σ(I). The unique feature of the structure is the presence of infinite chains composed of two parallel chains of scandium octahedra which share a common edge. Chlorine atoms cap all outward facing metal triangles and also bridge (a) to and (b) between isolated Sc(III) metal ions, giving the connectivity description (ScClb4/2Cla2/3) ∞(Sc6Cl6Cla 4/3)∞ where the fractional atoms Cla and Clb provide the bridging functions. The structure is thus intermediate between the single chains of octahedra found in GdCl1.5 and the infinite two-dimensional sheets of edge-shared octahedra in ScCl. Magnetic susceptibility measurements between 79 and 297 K (Faraday method) indicate a Curie-Weiss behavior above ∼120 K (μ = 1.04 μB, θ = -498 K) with evidence of magnetic ordering at T <79 K. This and a sharp EPR signal at room temperature (g = 1.97) are interpreted in terms of localized, weakly interacting (at 297 K) d1 configurations for two (of six) particular scandium atoms in the chain. The occurrence of strongly bonded and well-separated metal chains and the physical properties resulting therefrom suggest the phase can be described as a crystalline analogue of a metal fiber composite.",
author = "Poeppelmeier, {Kenneth R} and Corbett, {John D.}",
year = "1977",
language = "English",
volume = "16",
pages = "1107--1111",
journal = "Inorganic Chemistry",
issn = "0020-1669",
publisher = "American Chemical Society",
number = "5",

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T1 - Metal-metal bonding in reduced scandium halides. Synthesis and characterization of heptascandium decachloride (Sc7Cl10). A novel metal-chain structure

AU - Poeppelmeier, Kenneth R

AU - Corbett, John D.

PY - 1977

Y1 - 1977

N2 - The reaction of scandium metal with scandium trihalide in a sealed tantalum container under a temperature gradient 880-900 °C results in transport of monocrystals of heptascandium decachloride (ScCl1.43) to the hot zone. The compound crystallizes in the monoclinic space group C2/m with a = 18.620 (7) Å, b = 3.5366 (7) Å, c = 12.250 (5) Å, β = 91.98 (4)°, and Z = 2. Full-matrix least-squares refinement of all atoms with anisotropic thermal parameters gave final residuals R = 0.059 and Rw = 0.072 for 705 independent reflections with 2θ ≤ 50° and I > 3σ(I). The unique feature of the structure is the presence of infinite chains composed of two parallel chains of scandium octahedra which share a common edge. Chlorine atoms cap all outward facing metal triangles and also bridge (a) to and (b) between isolated Sc(III) metal ions, giving the connectivity description (ScClb4/2Cla2/3) ∞(Sc6Cl6Cla 4/3)∞ where the fractional atoms Cla and Clb provide the bridging functions. The structure is thus intermediate between the single chains of octahedra found in GdCl1.5 and the infinite two-dimensional sheets of edge-shared octahedra in ScCl. Magnetic susceptibility measurements between 79 and 297 K (Faraday method) indicate a Curie-Weiss behavior above ∼120 K (μ = 1.04 μB, θ = -498 K) with evidence of magnetic ordering at T <79 K. This and a sharp EPR signal at room temperature (g = 1.97) are interpreted in terms of localized, weakly interacting (at 297 K) d1 configurations for two (of six) particular scandium atoms in the chain. The occurrence of strongly bonded and well-separated metal chains and the physical properties resulting therefrom suggest the phase can be described as a crystalline analogue of a metal fiber composite.

AB - The reaction of scandium metal with scandium trihalide in a sealed tantalum container under a temperature gradient 880-900 °C results in transport of monocrystals of heptascandium decachloride (ScCl1.43) to the hot zone. The compound crystallizes in the monoclinic space group C2/m with a = 18.620 (7) Å, b = 3.5366 (7) Å, c = 12.250 (5) Å, β = 91.98 (4)°, and Z = 2. Full-matrix least-squares refinement of all atoms with anisotropic thermal parameters gave final residuals R = 0.059 and Rw = 0.072 for 705 independent reflections with 2θ ≤ 50° and I > 3σ(I). The unique feature of the structure is the presence of infinite chains composed of two parallel chains of scandium octahedra which share a common edge. Chlorine atoms cap all outward facing metal triangles and also bridge (a) to and (b) between isolated Sc(III) metal ions, giving the connectivity description (ScClb4/2Cla2/3) ∞(Sc6Cl6Cla 4/3)∞ where the fractional atoms Cla and Clb provide the bridging functions. The structure is thus intermediate between the single chains of octahedra found in GdCl1.5 and the infinite two-dimensional sheets of edge-shared octahedra in ScCl. Magnetic susceptibility measurements between 79 and 297 K (Faraday method) indicate a Curie-Weiss behavior above ∼120 K (μ = 1.04 μB, θ = -498 K) with evidence of magnetic ordering at T <79 K. This and a sharp EPR signal at room temperature (g = 1.97) are interpreted in terms of localized, weakly interacting (at 297 K) d1 configurations for two (of six) particular scandium atoms in the chain. The occurrence of strongly bonded and well-separated metal chains and the physical properties resulting therefrom suggest the phase can be described as a crystalline analogue of a metal fiber composite.

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