Nanometer range correlations between molecular orientations in liquids of molecules with perfect tetrahedral shape: CCl4, SiCl4, GeCl4, and SnCl4

Abstract

Neutron and x-ray weighted total scattering structure factors of liquid carbon, silicon, germanium, and tin tetrachlorides, CCl(4), SiCl(4), GeCl(4), and SnCl(4), have been interpreted by means of reverse Monte Carlo modeling. For each material the two sets of diffraction data were modeled simultaneously, thus providing sets of particle coordinates that were consistent with two experimental structure factors within errors. From these particle configurations, partial radial distribution functions, as well as correlation functions characterizing mutual orientations of molecules as a function of distance between molecular centers were calculated. Via comparison with reference systems, obtained by hard sphere Monte Carlo simulations, we demonstrate that orientational correlations characterizing these liquids are much longer ranged than expected, particularly in carbon tetrachloride.

Structural and electronic features of binary Li2S-P2S5 glasses

“…Actually, the heights of the FSDP in S N ( Q ) are greater than those in S X ( Q ). Not only glasses, but also the molecular liquids CCl 4 , SiCl 4 , GeCl 4 , and SnCl 4 with the regular X Cl 4 tetrahedral anion ( X  = C, Si, Ge, and Sn) have a similar FSDP at approximately Q  = 1.2 Å −1 , despite these liquids not having the interconnections of regular X Cl 4 tetrahedral anions27. Although the relationship between the FSDP and the topology of the network is still not well understood, it is suggested that a pseudo network of P-P correlations contributes to the stabilization of the glassy structure.…”

Is there a common orientational order for the liquid phase of tetrahedral molecules?

“…[1][2][3][4] It is of interest though to proceed to a direct comparison of both liquids in order to ascertain whether there might be any relevant quantitative difference. This will also provide a basic framework for the comparative study of the rest of the liquids to be reported in the next section.…”

“…This finding has very recently been corroborated in a reverse Monte Carlo ͑RMC͒ analysis of combined neutron and ͑new͒ x-ray scattering measures. 2 As this methodology is not limited to this phase and/or compound, it has also been applied to investigate the similarities and differences between the liquid and plastic phases for both carbon tetrachloride and neopentane 3 and to the gas-liquid coexistence line for carbon tetrachloride; 4 recently, Pusztai et al applied this methodology to tin iodide 5 and several chlorinated compounds. 2,6 In order to complete the program outlined in Ref.…”

“…2 As this methodology is not limited to this phase and/or compound, it has also been applied to investigate the similarities and differences between the liquid and plastic phases for both carbon tetrachloride and neopentane 3 and to the gas-liquid coexistence line for carbon tetrachloride; 4 recently, Pusztai et al applied this methodology to tin iodide 5 and several chlorinated compounds. 2,6 In order to complete the program outlined in Ref. 1, this work is devoted to an old question, namely, the possible existence of a common orientational order for liquids composed of tetrahedral molecules.…”

“…1, this work is devoted to an old question, namely, the possible existence of a common orientational order for liquids composed of tetrahedral molecules. 2,[6][7][8][9][10][11][12][13][14][15][16][17][18][19] In fact, up to now the discussion has been mainly circumscribed to the liquid tetrachlorides, 2,6,[8][9][10][12][13][14][15][16][17][18][19] and as it was the case for the nature and range of orientational correlations in carbon tetrachloride, no agreement seems to exist on this issue; while some authors have rejected the existence of a common orientational order, 12,13 others have supported it. 14,19 The most recent contribution is the study by Pothoczki and Pusztai 6 in which they apply the aforementioned classification method 1 to a comparison of the liquid phases of TiCl 4 and VCl 4 , concluding that their structural features are nearly indistinguishable.…”