Five coordinated Mn in Ba₄Mn₂Si₂Te₉: synthesis, crystal structure, physical properties, and electronic structure

Abstract

We report the synthesis of single-crystals of a new transition metal-containing quaternary chalcogenide, Ba4Mn2Si2Te9, synthesized by the solid-state method at 1273 K. A single-crystal X-ray diffraction study shows that it...

Low thermal conductivity in a new mixed metal telluride Mn1.8(1)In0.8(1)Si2Te6

“…The (In1/Mn1)-Te bond distance (2.9696(6) Å) in the title structure is intermediate to the In 3+ -Te distances in the In 2 Si 2 Te 6 (2.994(1) Å to 2.996(1) Å) 40 structure and the Mn2-Te distances observed in the Mn 3 Si 2 Te 6 (2.908(1) Å) 39 structure. The Mn2-Te distance of 2.8831 Å found in Mn 1.8(1) In 0.8(1) Si 2 Te 6 is fairly close to the Mn 2+ -Te distance reported for the Ba 4 Mn 2 Si 2 Te 9 (2.721 Å to 2.866 Å) 41 and Mn 3 Si 2 Te 6 (Mn1-Te = 2.933(1) Å to 2.952(1) Å) 39 structures. The Si 3+ -Te bond distance in Mn 1.8(1) In 0.8(1) Si 2 Te 6 (2.507(1) Å) is in good agreement with the Ba 4 Mn 2 Si 2 Te 9 (2.492(2) Å-2.515(1) Å) 41 Furthermore, using the EXPO 2014 software, 42 we performed BVS calculations for each atom in the Mn 1.8(1) In 0.8(1) Si 2 Te 6 structure to validate the assigned oxidation states of the elements.…”

“…The Mn2-Te distance of 2.8831 Å found in Mn 1.8(1) In 0.8(1) Si 2 Te 6 is fairly close to the Mn 2+ -Te distance reported for the Ba 4 Mn 2 Si 2 Te 9 (2.721 Å to 2.866 Å) 41 and Mn 3 Si 2 Te 6 (Mn1-Te = 2.933(1) Å to 2.952(1) Å) 39 structures. The Si 3+ -Te bond distance in Mn 1.8(1) In 0.8(1) Si 2 Te 6 (2.507(1) Å) is in good agreement with the Ba 4 Mn 2 Si 2 Te 9 (2.492(2) Å-2.515(1) Å) 41 Furthermore, using the EXPO 2014 software, 42 we performed BVS calculations for each atom in the Mn 1.8(1) In 0.8(1) Si 2 Te 6 structure to validate the assigned oxidation states of the elements. The assigned formal oxidation states of all the atoms are in reasonably good agreement with the corresponding calculated BVS values (see Table 4) except for Mn2, which is slightly overbonded (BVS = 2.4).…”

“…The Mn2–Te distance of 2.8831 Å found in Mn 1.8(1) In 0.8(1) Si 2 Te 6 is fairly close to the Mn 2+ –Te distance reported for the Ba 4 Mn 2 Si 2 Te 9 (2.721 Å to 2.866 Å) 41 and Mn 3 Si 2 Te 6 (Mn1–Te = 2.933(1) Å to 2.952(1) Å) 39 structures. The Si 3+ –Te bond distance in Mn 1.8(1) In 0.8(1) Si 2 Te 6 (2.507(1) Å) is in good agreement with the Ba 4 Mn 2 Si 2 Te 9 (2.492(2) Å–2.515(1) Å) 41 and In 2 Si 2 Te 6 (2.505(1) Å) 40 structures. The distance between two Si atoms (2.315(12) Å) in the title structure is also in excellent agreement with the Si 3+ –Si 3+ distances of the Si 2 Te 6 dimers of the Ba 4 Mn 2 Si 2 Te 9 (2.327(4) Å) 41 and In 2 Si 2 Te 6 (2.298(1) Å) 40 structures.…”

“…The Si 3+ –Te bond distance in Mn 1.8(1) In 0.8(1) Si 2 Te 6 (2.507(1) Å) is in good agreement with the Ba 4 Mn 2 Si 2 Te 9 (2.492(2) Å–2.515(1) Å) 41 and In 2 Si 2 Te 6 (2.505(1) Å) 40 structures. The distance between two Si atoms (2.315(12) Å) in the title structure is also in excellent agreement with the Si 3+ –Si 3+ distances of the Si 2 Te 6 dimers of the Ba 4 Mn 2 Si 2 Te 9 (2.327(4) Å) 41 and In 2 Si 2 Te 6 (2.298(1) Å) 40 structures.…”

“…and In 2 Si 2 Te 6 (2.505(1) Å)40 structures. The distance between two Si atoms 3+ distances of the Si 2 Te 6 dimers of the Ba 4 Mn 2 Si 2 Te 9 (2.327(4) Å)41 and In 2 Si 2 Te 6 (2.298(1) Å)40 structures. Te 6 structure is derived from the In 2 Si 2 Te 6 and Mn 3 Si 2 Te 6 structures, the assignment of formal oxidation states to the atoms of the quaternary structure is In 3+ ) 0.8 (Si 3+ ) 2 (Te 2− ) 6 .…”