Contents lists available at ScienceDirect Materials Today Communications journal homepage: www.elsevier.com/locate/mtcomm Amorphization diversity driven by high-energy mechanical milling in β- As 4 S 4 polymorph Oleh Shpotyuk a,b, ⁎ , Pavlo Demchenko c , Yaroslav Shpotyuk d,e , Zdenka Bujňáková f , Peter Baláž f , Malgorzata Hyla a , Vitaliy Boyko b a Faculty of Mathematics and Natural Sciences, Jan Dlugosz University in Czestochowa, 13/15, al. Armii Krajowej, Czestochowa, 42200, Poland b Department of Optical Glass and Ceramics, Vlokh Institute of Physical Optics, 23, Dragomanova st., Lviv, 79005, Ukraine c Department of Inorganic Chemistry, Ivan Franko National University of Lviv, 6-8, Kyryla i Myfodia st., Lviv, 79005, Ukraine d Department of Sensor and Semiconductor Electronics, Ivan Franko National University of Lviv, 107, Tarnavskoho st., Lviv, 79017, Ukraine e Institute of Physics, University of Rzeszow, 1, Pigonia st., 35959, Rzeszow, Poland f Institute of Geotechnics of Slovak Academy of Sciences, 45, Watsonova str., Košice, 04001, Slovakia ARTICLE INFO Keywords: Ab-initio quantum-chemical modelling Molecular clusters Amorphization Mechanical milling Arsenic monosulphide β-As 4 S 4 ABSTRACT Amorphization scenarios in multiparticulate nanocomposites based on directly synthesized β-As 4 S 4 activated by high-energy mechanical milling are identified employing X-ray diffraction analysis complemented with ab initio quantum-chemical computational modelling. Coexistance of nanocrystalline and amorphous phases is crucial feature of these nanocomposites, their medium-range structure being reconstructed assuming diffuse halos as arising from remnants of inter-planar correlations with ∼5.3–5.5 Ǻ Bragg-diffraction spacing supplemented by Ehrenfest-diffraction contribution from most pronounced inter-molecular correlations. Full hierarchy of mole- cular-breaking events comprising transitions from As 4 S 4 cage-like molecule to its network-forming derivatives is computed. The optimally-constrained single-broken clusters keeping one hexagon and two adjacent pentagons in atomic arrangement are supposed to be responsible for amorphization in β-As 4 S 4 . The over-constrained triple- broken chains are character for amorphization in monoparticulate (composed exceptionally by β-As 4 S 4 crys- tallites) and biparticulate (composed by mixed β-As 4 S 4 and magnetite Fe 3 O 4 crystallites) grinding media, the estimated density of accompanied amorphous phase being 3.43 g⋅ cm -3 . Strong amorphization scenario obeying “shell” kinetics model occurs in triparticulate β-As 4 S 4 -based solution modified by Fe 3 O 4 (few tens nm) and ZnS (below few nm) crystallites. The latter acting as solid solvent provide sufficient energy gained from collisions with hard magnetite particles to soft amorphized substance composed mainly by double-broken As 4 S 4 molecules keeping pentagon rings in atomic arrangement. This effect is identified as ZnS-assisted milling-driven arsenic monosulphide amorphization in 1⋅β-As 4 S 4 -4⋅ZnS-1⋅Fe 3 O 4 grinding solution. 1. Introduction Nanostructurization of insoluble and poorly soluble drug inorganic substances is one of the most efficient ways to modify their biomedical functionality, which otherwise is harmful by substantially restricted bioavailability of their macroscopic bulky forms [1–4]. In many prac- tically important solid-state systems, such transition to nanosized en- tities is accompanied by interphase transformations (viz. the changes in phase composition), including structural disordering revealed through solid-state amorphization [3–7]. Thus, e.g., strong amorphization ten- dencies are proper to over-stoichiometric arsenic monosulphide poly- morphs such as high-temperature modification of tetra-arsenic tetra- sulphide, the β-As 4 S 4 (arsenic monosulphide), which being affected to high-energy mechanical milling (MM), demonstrate an obvious pro- pensity towards amorphous state with a variety of metastable phases [8–11]. Recently, we have found complete MM-driven amorphization in partially crystalline synthetic As 45 S 55 alloy [12]. As was shown by Hruby [13], the arsenic monosulphide prepared by direct synthesis from elemental ingredients never behaved as chemically well-defined compound, but rather as mixture of phases with considerable amount of amorphous one. Thermally-induced crystalline-to-amorphous alteration was studied recently in this polymorph affected to MM employing temperature-modulated DSC TOPEM® method [14]. Brazhkin et al. [15,16] proved that amorphization under high pressures (a few GPa) https://doi.org/10.1016/j.mtcomm.2019.100679 Received 16 July 2019; Received in revised form 25 September 2019; Accepted 29 September 2019 ⁎ Corresponding author at: Faculty of Mathematics and Natural Sciences, Jan Dlugosz University in Czestochowa, 13/15, al. Armii Krajowej, Czestochowa, 42200, Poland. E-mail address: olehshpotyuk@yahoo.com (O. Shpotyuk). Materials Today Communications 21 (2019) 100679 Available online 06 October 2019 2352-4928/ © 2019 Elsevier Ltd. All rights reserved. T