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Title: Polymorphism and optical properties in [NH{sub 4}][InSe{sub 2}]

The solvothermal synthesis and characterization of two indium selenides with stoichiometry [NH{sub 4}][InSe{sub 2}] is described. Yellow [NH{sub 4}][InSe{sub 2}] (1), which exhibits a layered structure, was initially prepared in an aqueous solution of trans-1,4-diaminocyclohexane, and subsequently using a concentrated ammonia solution. A red polymorph of one-dimensional character, [NH{sub 4}][InSe{sub 2}] (2), was obtained using 3,5-dimethylpyridine as solvent. [NH{sub 4}][InSe{sub 2}] (1) crystallizes in the non-centrosymmetric space group Cc (a=11.5147(6), b=11.3242(6), c=15.9969(9) Å and β=100.354(3)°). The structural motif of the layers is the In{sub 4}Se{sub 10} adamantane unit, composed of four corner-linked InSe{sub 4} tetrahedra. These units are linked by their corners, forming [InSe{sub 2}]{sup −} layers which are stacked back to back along the c-direction, and interspaced by [NH{sub 4}]{sup +}cations. The one-dimensional polymorph, (2), crystallizes in the tetragonal space group, I4/mcm (a=8.2519(16), c=6.9059 (14) Å). This structure contains infinite chains of edge-sharing InSe{sub 4} tetrahedra separated by [NH{sub 4}]{sup +} cations. - Graphical abstract: Two polymorphic forms of [NH{sub 4}][InSe{sub 2}], which are yellow and red, have been prepared and their optical properties investigated. Highlights: • Two new indium selenides prepared by a solvothermal method. • Depending on synthesis conditions, two polymorphic forms of [NH{sub 4}][InSe{sub 2}] prepared.more » • Layered polymorph contains In{sub 4}Se{sub 10} adamantane clusters, linked by their corners. • One-dimensional polymorph contains [InSe{sub 2}]{sup −} chains of edge-sharing tetrahedra. • Non-centrosymmetric layered polymorph shows a second harmonic generation response.« less
Authors:
 [1] ;  [2] ;  [1] ;  [1]
  1. Institute of Chemical Sciences, Heriot-Watt University, Edinburgh, Scotland EH14 4AS (United Kingdom)
  2. Department of Physics, University of Warwick, Coventry CV4 7AL (United Kingdom)
Publication Date:
OSTI Identifier:
22274033
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Solid State Chemistry; Journal Volume: 204; Other Information: Copyright (c) 2013 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; AMMONIA; AQUEOUS SOLUTIONS; CYCLOALKANES; HARMONIC GENERATION; INDIUM SELENIDES; LAYERS; OPTICAL PROPERTIES; SPACE GROUPS; SYNTHESIS; TETRAGONAL LATTICES