Atomic Density versus Average Coordination Number in Ge–In–Se Glasses

Abstract

The variation of the atomic density ϱ with the average coordination number Z for glasses belonging to the GexIn6Se94—x and GexIn12Se88—x families of the Ge–In–Se system is investigated. The ϱ— Z dependence displays broad maxima at Z values of 2.42 and 2.58 for families with 6 and 12 at% In, respectively. These maxima are ascribed to changes from a floppy to a rigid type network and from a two‐dimensional layered structure to a three‐dimensional network, respectively. The minima exhibited in the ϱ— Z dependence at Z = 2.63 for the In6 family and at Z = 2.71 for the In12 family, corresponding to the tie‐line compositions, are attributed to chemical ordering effects.

Topology of Chemical Ordering in Sb-S-Ge System

“…This negative shift ðDm av ¼ 0:07Þ in the threshold value observed in this work can be traced to the inclusion of the heavy metal Sb [11] in to the covalent Ge-S network. This leads to the formation of iono-covalent bonds [20]. Tanaka's estimate of the balance condition, however, is not taking account of this factor.…”

An investigation of Al2O3 induced variations in the structural parameters in strontium borosilicate glasses using solid state NMR

“…The average coordination number of network forming oxides ( n o A ) is calculated using the formula 12 where, F A , is the atomic fraction of the respective network forming units such as SiO 4 , BO 3 , BO 4 , and AlO 4 , which is obtained from the deconvolution of the MAS spectra of 29 Si, 27 Al, and 11 B. C A is the coordination number of the corresponding network forming oxide ‘A’.…”

“…These structural parameters play a key role in understanding the topology of the glasses and a few studies have been reported that associate the effect of these parameters on the thermo- physical properties of the glasses. 11–15 Zeidler et al studied the pressure dependence of n o A within a series of silicate, borosilicate and aluminosilicate glasses and X. Du et al .…”

“…These structural parameters play a key role in understanding the topology of the glasses and a few studies have been reported that associate the effect of these parameters on the thermo-physical properties of the glasses. [11][12][13][14][15] A and the structure of silicone and germanium oxide glasses. 16,17 In this study, a series of strontium alumina borosilicate glasses, prepared with a systematic substitution of B 2 O 3 by Al 2 O 3 were analyzed using multinuclear solid state NMR.…”

Structure of GeSe4–In and GeSe5–In glasses

“…The simulation boxes contained 18 000 atoms. The number densities ρ used in the simulations (table 1) were calculated by compilation of the experimental mass densities reported in the literature [1,31] and our own measurements (unpublished). The minimum interatomic distances (cut offs) applied in the final simulation runs (used to produce configurations for further analysis) are listed in table 2.…”