title: Conversion Reactions of Solids: From a Surprising Three-Step Mechanism towards Directed Product Formation.
abstract: Directed conversion reactions from binary to multinary compounds are discovered from the reaction of Bi2 S3 and Bi2 Se3 with NiCl2 ⋅6 H2 O in polyol media under basic conditions. Control of the synthesis conditions allows the preparation of NiBiSe and superconducting Ni3 Bi2 S2 and Ni3 Bi2 Se2 . The formation of Ni3 Bi2 S2 from Bi2 S3 is found from an unexpected three-step reaction path with Bi and NiBi as intermediates. In the more complex Ni/Bi/Se system, the mechanism found can be used to selectively direct the reaction between the competing ternaries and to suppress side-product formation. Contrary to solid-state reactions (500-900 °C) control of product formation is reached at reaction temperatures and times between 166-300 °C and 0.5-10 h, respectively. The formation of different phases is discussed from results of DFT calculations.
authors.affiliation: Institute for Materials Resource Management, University of Augsburg, Universitätsstraße 1a, 86159, Augsburg, Germany.|Institute of Inorganic Chemistry, University of Regensburg, Universitätsstraße 31, 93040, Regensburg, Germany.
authors.forename: Stefan Michael
authors.initials: SM
authors.lastname: Rommel
authors.affiliation: Institute of Inorganic Chemistry, University of Regensburg, Universitätsstraße 31, 93040, Regensburg, Germany.
authors.forename: Alexander
authors.initials: A
authors.lastname: Krach
authors.affiliation: Institute of Inorganic Chemistry, University of Regensburg, Universitätsstraße 31, 93040, Regensburg, Germany.
authors.forename: Philipp
authors.initials: P
authors.lastname: Peter
authors.affiliation: Departement of Chemistry, TU Munich, Lichtenbergstr. 4, 85474, Garching, Germany. richard.weihrich@chemie.uni-regensburg.de.|Institute of Inorganic Chemistry, University of Regensburg, Universitätsstraße 31, 93040, Regensburg, Germany. richard.weihrich@chemie.uni-regensburg.de.
authors.forename: Richard
authors.identifier: http://orcid.org/0000-0001-5359-5341
authors.initials: R
authors.lastname: Weihrich
keywords: formation mechanism; nanoparticles; polyol process; synthetic methods; ternary chalcogenide