Empfindlichkeit des Nachweises von Blei- und Sulfid-Ion als Bleisulfobromid [(PbBr)2S]

Nanocrystals of Lead Chalcohalides: A Series of Kinetically Trapped Metastable Nanostructures

“…Both phases have the same Pb 4 S 3 X 2 stoichiometry, crystallize in the same space group, and have an equivalent atomic layout (Figure S21). For example, in both structures the Pb atoms form layers along the b axis, while the anions are alternated in sulfur-only and mixed sulfur–bromine layers . This evidence confirms that we have discovered a structural variation in a yet underexplored family of compounds: our hypothesis is that Pb 4 S 3 Br 2 is a kinetically trapped high-pressure metastable structure as well.…”

“…For example, in both structures the Pb atoms form layers along the b axis, while the anions are alternated in sulfur-only and mixed sulfur−bromine layers. 18 This evidence confirms that we have discovered a structural variation in a yet underexplored family of compounds: our hypothesis is that Pb 4 S 3 Br 2 is a kinetically trapped high-pressure metastable structure as well. First, the reader should be reminded that the room-pressure pseudobinary phase diagram PbS−PbBr 2 contemplates only PbS, PbBr 2 , and Pb 7 S 2 Br 10 as stable phases.…”

“…15 , 16 For the PbS–PbBr 2 system, a few additional tentative stoichiometries have been identified. 16 − 19 In various works, different compositions such as (PbBr) 2 S, 17 , 18 “2PbS–PbCl 2 ”, and “2PbS–PbBr 2 ” 16 , 19 have been reported and even partially characterized, with Rabenau et al demonstrating that “2PbS–PbBr 2 ” thermally decomposes into a mixture of Pb 7 S 2 Br 10 and PbS. 16 However, in the case of those latter phases the crystal structures were not determined, therefore precluding further investigations and leaving the door open to the possibility of identifying new lead chalcohalides.…”

“…Over the past decade, lead chalcogenides first and lead-halide perovskites later have been among the cornerstone materials in nanocrystal (NC) research. − Nowadays, many fundamental questions on these materials have been answered, and as interest in them is progressively shifting toward their applications, the quest for a new generation of inorganic NCs with appealing optoelectronic properties is becoming more compelling. An interesting class of compounds, which has hardly been explored on the nanoscale to date, is that of metal chalcohalides. − These materials offer a rich solid-state chemistry and structural diversity, , and they have proven to be useful for applications ranging from solar energy conversion to thermoelectrics, hard radiation detection, and superconductivity. − Among them, lead chalcohalides have been investigated in the past, up to the complete determination of the atmospheric pressure PbY–PbX 2 binary phase diagrams (Y = S, Se; X = Cl, Br, I), a search that led to the discovery and structural characterization of two stable (Pb 5 S 2 I 6 and Pb 7 S 2 Br 10 ) as well as some metastable chalcohalide structures (Pb 4 SCl 6 and Pb 4 SeBr 6 ). , For the PbS–PbBr 2 system, a few additional tentative stoichiometries have been identified. − In various works, different compositions such as (PbBr) 2 S, , “2PbS–PbCl 2 ”, and “2PbS–PbBr 2 ” , have been reported and even partially characterized, with Rabenau et al demonstrating that “2PbS–PbBr 2 ” thermally decomposes into a mixture of Pb 7 S 2 Br 10 and PbS . However, in the case of those latter phases the crystal structures were not determined, therefore precluding further investigations and leaving the door open to the possibility of identifying new lead chalcohalides.…”