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Title: Ultralow Lattice Thermal Conductivity in the Aikinite Structure Family, Cu x Pb x Bi 2–x S 3 , and Thermoelectric Properties of Cu 0.14 Pb 0.14 Bi 1.86 S 3
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Author(s) / Creator(s):
; ; ; ; ; ;
Date Published:
Journal Name:
ACS Applied Energy Materials
Page Range / eLocation ID:
14222 to 14230
Medium: X
Sponsoring Org:
National Science Foundation
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  1. null (Ed.)
    A ternary derivative of Li 3 Bi with the composition Li 3– x – y In x Bi ( x  ≃ 0.14, y  ≃ 0.29) was produced by a mixed In+Bi flux approach. The crystal structure adopts the space group Fd \overline{3} m (No. 227), with a = 13.337 (4) Å, and can be viewed as a 2 × 2 × 2 superstructure of the parent Li 3 Bi phase, resulting from a partial ordering of Li and In in the tetrahedral voids of the Bi fcc packing. In addition to the Li/In substitutional disorder, partial occupation of some Li sites is observed. The Li deficiency develops to reduce the total electron count in the system, counteracting thereby the electron doping introduced by the In substitution. First-principles calculations confirm the electronic rationale of the observed disorder. 
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  2. Abstract

    Reactions of the IrVhydride [MeBDIDipp]IrH4{BDI=(Dipp)NC(Me)CH(Me)CN(Dipp); Dipp=2,6‐iPr2C6H3} with E[N(SiMe3)2]2(E=Sn, Pb) afforded the unusual dimeric dimetallotetrylenes ([MeBDIDipp]IrH)2(μ2‐E)2in good yields. Moreover, ([MeBDIDipp]IrH)2(μ2‐Ge)2was formed in situ from thermal decomposition of [MeBDIDipp]Ir(H)2Ge[N(SiMe3)2]2. These reactions are accompanied by liberation of HN(SiMe3)2and H2through the apparent cleavage of an E−N(SiMe3)2bond by Ir−H. In a reversal of this process, ([MeBDIDipp]IrH)2(μ2‐E)2reacted with excess H2to regenerate [MeBDIDipp]IrH4. Varying the concentrations of reactants led to formation of the trimeric ([MeBDIDipp]IrH2)3(μ2‐E)3. The further scope of this synthetic route was investigated with group 15 amides, and ([MeBDIDipp]IrH)2(μ2‐Bi)2was prepared by the reaction of [MeBDIDipp]IrH4with Bi(NMe2)3or Bi(OtBu)3to afford the first example of a “naked” two‐coordinate Bi atom bound exclusively to transition metals. A viable mechanism that accounts for the formation of these products is proposed. Computational investigations of the Ir2E2(E=Sn, Pb) compounds characterized them as open‐shell singlets with confined nonbonding lone pairs at the E centers. In contrast, Ir2Bi2is characterized as having a closed‐shell singlet ground state.

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