New uranium chalcoantimonates, RbU2SbS8 and KU2SbSe8, with a polar noncentrosymmetric structure

Kyoung Shin Choi, Mercouri G Kanatzidis

Research output: Contribution to journalArticle

26 Citations (Scopus)

Abstract

The new compounds, RbU2SbS8 and KU2SbSe8, were prepared as golden-black, blocklike crystals by the polychalcogenide molten flux method. RbU2SbS8 crystallizes in the monoclinic space group Cm with a = 7.9543(9) ̊, b = 11.0987(13) ̊, c = 7.2794(10) ̊, β= 106.030(2)°, and Z = 2. The compound has a two-dimensional character with layers running perpendicular to the c-axis. The coordination geometry around the U4+ atoms is best described as a bicapped trigonal prism. The trigonal prisms share triangular faces with neighboring prisms, forming one-dimensional columns along the α-axis. The columns are then joined to construct sheets by sharing capping S atoms. Sb3+ ions are sitting at the center of a slightly distorted seesaw coordination environment (CN = 4). Rb+ ions are stabilized in 8-coordinate bicapped trigonal prismatic sites. KU2SbSe8 crystallizes in the monoclinic space group Cm with a = 11.5763-(2) ̊, b = 8.2033(1) ̊, c = 15.2742(1) ̊, β= 112.22(2)°, and Z = 4. KU2SbSe8 has essentially the same structure as RbU2SbS8. However, Sb3+ and K+ ions appear disordered in every other layer, resulting in a different unit cell. RbU2SbS8 is a semiconductor with a band gap of 1.38 eV. The band gap of KU2SbSe8 could not be determined precisely due to the presence of overlapping intense f-f transitions in the region (0.5-1.1 eV). The Raman spectra show the disulfide stretching vibration in RbU2SbS8 at 479 cm-1 and the diselenide stretching vibration in KU2SbSe8 at 252 cm-1. Magnetic susceptibility measurements indicate the presence of U4+ centers in the compounds. The compounds do not melt below 1000 °C under vacuum.

Original languageEnglish
Pages (from-to)2613-2618
Number of pages6
JournalChemistry of Materials
Volume11
Issue number9
Publication statusPublished - 1999

Fingerprint

Uranium
Prisms
Ions
Stretching
Energy gap
Atoms
Magnetic susceptibility
Disulfides
Molten materials
Raman scattering
Vacuum
Semiconductor materials
Fluxes
Crystals
Geometry

ASJC Scopus subject areas

  • Materials Chemistry
  • Materials Science(all)

Cite this

New uranium chalcoantimonates, RbU2SbS8 and KU2SbSe8, with a polar noncentrosymmetric structure. / Choi, Kyoung Shin; Kanatzidis, Mercouri G.

In: Chemistry of Materials, Vol. 11, No. 9, 1999, p. 2613-2618.

Research output: Contribution to journalArticle

@article{f7dec7b7e75a4e7893c5405c32c0fdec,
title = "New uranium chalcoantimonates, RbU2SbS8 and KU2SbSe8, with a polar noncentrosymmetric structure",
abstract = "The new compounds, RbU2SbS8 and KU2SbSe8, were prepared as golden-black, blocklike crystals by the polychalcogenide molten flux method. RbU2SbS8 crystallizes in the monoclinic space group Cm with a = 7.9543(9) ̊, b = 11.0987(13) ̊, c = 7.2794(10) ̊, β= 106.030(2)°, and Z = 2. The compound has a two-dimensional character with layers running perpendicular to the c-axis. The coordination geometry around the U4+ atoms is best described as a bicapped trigonal prism. The trigonal prisms share triangular faces with neighboring prisms, forming one-dimensional columns along the α-axis. The columns are then joined to construct sheets by sharing capping S atoms. Sb3+ ions are sitting at the center of a slightly distorted seesaw coordination environment (CN = 4). Rb+ ions are stabilized in 8-coordinate bicapped trigonal prismatic sites. KU2SbSe8 crystallizes in the monoclinic space group Cm with a = 11.5763-(2) ̊, b = 8.2033(1) ̊, c = 15.2742(1) ̊, β= 112.22(2)°, and Z = 4. KU2SbSe8 has essentially the same structure as RbU2SbS8. However, Sb3+ and K+ ions appear disordered in every other layer, resulting in a different unit cell. RbU2SbS8 is a semiconductor with a band gap of 1.38 eV. The band gap of KU2SbSe8 could not be determined precisely due to the presence of overlapping intense f-f transitions in the region (0.5-1.1 eV). The Raman spectra show the disulfide stretching vibration in RbU2SbS8 at 479 cm-1 and the diselenide stretching vibration in KU2SbSe8 at 252 cm-1. Magnetic susceptibility measurements indicate the presence of U4+ centers in the compounds. The compounds do not melt below 1000 °C under vacuum.",
author = "Choi, {Kyoung Shin} and Kanatzidis, {Mercouri G}",
year = "1999",
language = "English",
volume = "11",
pages = "2613--2618",
journal = "Chemistry of Materials",
issn = "0897-4756",
publisher = "American Chemical Society",
number = "9",

}

TY - JOUR

T1 - New uranium chalcoantimonates, RbU2SbS8 and KU2SbSe8, with a polar noncentrosymmetric structure

AU - Choi, Kyoung Shin

AU - Kanatzidis, Mercouri G

PY - 1999

Y1 - 1999

N2 - The new compounds, RbU2SbS8 and KU2SbSe8, were prepared as golden-black, blocklike crystals by the polychalcogenide molten flux method. RbU2SbS8 crystallizes in the monoclinic space group Cm with a = 7.9543(9) ̊, b = 11.0987(13) ̊, c = 7.2794(10) ̊, β= 106.030(2)°, and Z = 2. The compound has a two-dimensional character with layers running perpendicular to the c-axis. The coordination geometry around the U4+ atoms is best described as a bicapped trigonal prism. The trigonal prisms share triangular faces with neighboring prisms, forming one-dimensional columns along the α-axis. The columns are then joined to construct sheets by sharing capping S atoms. Sb3+ ions are sitting at the center of a slightly distorted seesaw coordination environment (CN = 4). Rb+ ions are stabilized in 8-coordinate bicapped trigonal prismatic sites. KU2SbSe8 crystallizes in the monoclinic space group Cm with a = 11.5763-(2) ̊, b = 8.2033(1) ̊, c = 15.2742(1) ̊, β= 112.22(2)°, and Z = 4. KU2SbSe8 has essentially the same structure as RbU2SbS8. However, Sb3+ and K+ ions appear disordered in every other layer, resulting in a different unit cell. RbU2SbS8 is a semiconductor with a band gap of 1.38 eV. The band gap of KU2SbSe8 could not be determined precisely due to the presence of overlapping intense f-f transitions in the region (0.5-1.1 eV). The Raman spectra show the disulfide stretching vibration in RbU2SbS8 at 479 cm-1 and the diselenide stretching vibration in KU2SbSe8 at 252 cm-1. Magnetic susceptibility measurements indicate the presence of U4+ centers in the compounds. The compounds do not melt below 1000 °C under vacuum.

AB - The new compounds, RbU2SbS8 and KU2SbSe8, were prepared as golden-black, blocklike crystals by the polychalcogenide molten flux method. RbU2SbS8 crystallizes in the monoclinic space group Cm with a = 7.9543(9) ̊, b = 11.0987(13) ̊, c = 7.2794(10) ̊, β= 106.030(2)°, and Z = 2. The compound has a two-dimensional character with layers running perpendicular to the c-axis. The coordination geometry around the U4+ atoms is best described as a bicapped trigonal prism. The trigonal prisms share triangular faces with neighboring prisms, forming one-dimensional columns along the α-axis. The columns are then joined to construct sheets by sharing capping S atoms. Sb3+ ions are sitting at the center of a slightly distorted seesaw coordination environment (CN = 4). Rb+ ions are stabilized in 8-coordinate bicapped trigonal prismatic sites. KU2SbSe8 crystallizes in the monoclinic space group Cm with a = 11.5763-(2) ̊, b = 8.2033(1) ̊, c = 15.2742(1) ̊, β= 112.22(2)°, and Z = 4. KU2SbSe8 has essentially the same structure as RbU2SbS8. However, Sb3+ and K+ ions appear disordered in every other layer, resulting in a different unit cell. RbU2SbS8 is a semiconductor with a band gap of 1.38 eV. The band gap of KU2SbSe8 could not be determined precisely due to the presence of overlapping intense f-f transitions in the region (0.5-1.1 eV). The Raman spectra show the disulfide stretching vibration in RbU2SbS8 at 479 cm-1 and the diselenide stretching vibration in KU2SbSe8 at 252 cm-1. Magnetic susceptibility measurements indicate the presence of U4+ centers in the compounds. The compounds do not melt below 1000 °C under vacuum.

UR - http://www.scopus.com/inward/record.url?scp=0001539736&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0001539736&partnerID=8YFLogxK

M3 - Article

AN - SCOPUS:0001539736

VL - 11

SP - 2613

EP - 2618

JO - Chemistry of Materials

JF - Chemistry of Materials

SN - 0897-4756

IS - 9

ER -