The Experts below are selected from a list of 9 Experts worldwide ranked by ideXlab platform
Gilles Frapper - One of the best experts on this subject based on the ideXlab platform.
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emergence of novel Hydrogen Chlorides under high pressure
Physical Chemistry Chemical Physics, 2017Co-Authors: Qingfeng Zeng, Artem R Oganov, Gilles FrapperAbstract:HCl is a textbook example of a polar covalent molecule, and has a wide range of industrial applications. Inspired by the discovery of unexpected stable sodium and potassium Chlorides, we performed systematic ab initio evolutionary searches for all stable compounds in the H–Cl system at pressures up to 400 GPa. Besides HCl, four new stoichiometries (H2Cl, H3Cl, H5Cl and H4Cl7) are found to be stable under pressure. Our predictions substantially differ from previous theoretical studies. We evidence a high significance of zero-point energy in determining phase stability. The newly discovered compounds display a rich variety of chemical bonding characteristics. At ambient pressure, H2, Cl2 and HCl molecular crystals are formed by weak intermolecular van der Waals interactions, and adjacent HCl molecules connect with each other to form asymmetric zigzag chains, which become symmetric under high pressure. In H5Cl, triangular H3+ cations are stabilized by electrostatic interactions with the anionic chloride network. Further increase of pressure drives H2 dimers to combine with H3+ cations to form H5+ units. We also found chlorine-based Kagome layers which are intercalated with zigzag HCl chains in H4Cl7. These findings could help to understand how varied bonding features can co-exist and evolve in one compound under extreme conditions.
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emergence of novel Hydrogen Chlorides under high pressure
arXiv: Materials Science, 2015Co-Authors: Qingfeng Zeng, Gilles Frapper, Artem R OganovAbstract:HCl, a 'textbook' example of a polar covalent molecule, is a well-known compound of Hydrogen and chlorine. Inspired by the discovery of unexpected stable stoichiometries of sodium Chlorides, we performed systematic searches for all stable compounds in the H-Cl system from ambient pressure to higher pressures up to 500 GPa using variable-composition ab initio evolutionary algorithm USPEX. We found several compounds that are stable under pressure, i.e. HCl, H$_2$Cl, H$_3$Cl, H$_5$Cl and H$_4$Cl$_7$, which display a rich variety of chemical bonding types. At ambient pressure, H$_2$, Cl$_2$ and HCl molecular crystals are formed by weak intermolecular van der Waals interactions and adjacent HCl molecules connect with each other to form asymmetric zigzag chains, which become symmetric under high pressure. In Hydrogen-rich Chlorides, H$_2$ and HCl react to form the thermodynamically stable H$_3$Cl crystalline compound in which molecular cyclic H$_3^+$ cations are stabilised by the Cl$^-$ sublattice. Increasing the amount of Hydrogen leads to stable solid-state H$_5$Cl, in which H$_2$ formally combines with H$_3^+$ to form H$_5^+$ cations. Additionally, chlorine-based Kagome layers are formed with intercalated zigzag HCl chains in chlorine-rich hydrides. These discoveries help to understand how varied bonding features can co-exist and evolve in one compound under extreme conditions.
Qingfeng Zeng - One of the best experts on this subject based on the ideXlab platform.
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emergence of novel Hydrogen Chlorides under high pressure
Physical Chemistry Chemical Physics, 2017Co-Authors: Qingfeng Zeng, Artem R Oganov, Gilles FrapperAbstract:HCl is a textbook example of a polar covalent molecule, and has a wide range of industrial applications. Inspired by the discovery of unexpected stable sodium and potassium Chlorides, we performed systematic ab initio evolutionary searches for all stable compounds in the H–Cl system at pressures up to 400 GPa. Besides HCl, four new stoichiometries (H2Cl, H3Cl, H5Cl and H4Cl7) are found to be stable under pressure. Our predictions substantially differ from previous theoretical studies. We evidence a high significance of zero-point energy in determining phase stability. The newly discovered compounds display a rich variety of chemical bonding characteristics. At ambient pressure, H2, Cl2 and HCl molecular crystals are formed by weak intermolecular van der Waals interactions, and adjacent HCl molecules connect with each other to form asymmetric zigzag chains, which become symmetric under high pressure. In H5Cl, triangular H3+ cations are stabilized by electrostatic interactions with the anionic chloride network. Further increase of pressure drives H2 dimers to combine with H3+ cations to form H5+ units. We also found chlorine-based Kagome layers which are intercalated with zigzag HCl chains in H4Cl7. These findings could help to understand how varied bonding features can co-exist and evolve in one compound under extreme conditions.
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emergence of novel Hydrogen Chlorides under high pressure
arXiv: Materials Science, 2015Co-Authors: Qingfeng Zeng, Gilles Frapper, Artem R OganovAbstract:HCl, a 'textbook' example of a polar covalent molecule, is a well-known compound of Hydrogen and chlorine. Inspired by the discovery of unexpected stable stoichiometries of sodium Chlorides, we performed systematic searches for all stable compounds in the H-Cl system from ambient pressure to higher pressures up to 500 GPa using variable-composition ab initio evolutionary algorithm USPEX. We found several compounds that are stable under pressure, i.e. HCl, H$_2$Cl, H$_3$Cl, H$_5$Cl and H$_4$Cl$_7$, which display a rich variety of chemical bonding types. At ambient pressure, H$_2$, Cl$_2$ and HCl molecular crystals are formed by weak intermolecular van der Waals interactions and adjacent HCl molecules connect with each other to form asymmetric zigzag chains, which become symmetric under high pressure. In Hydrogen-rich Chlorides, H$_2$ and HCl react to form the thermodynamically stable H$_3$Cl crystalline compound in which molecular cyclic H$_3^+$ cations are stabilised by the Cl$^-$ sublattice. Increasing the amount of Hydrogen leads to stable solid-state H$_5$Cl, in which H$_2$ formally combines with H$_3^+$ to form H$_5^+$ cations. Additionally, chlorine-based Kagome layers are formed with intercalated zigzag HCl chains in chlorine-rich hydrides. These discoveries help to understand how varied bonding features can co-exist and evolve in one compound under extreme conditions.
Artem R Oganov - One of the best experts on this subject based on the ideXlab platform.
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emergence of novel Hydrogen Chlorides under high pressure
Physical Chemistry Chemical Physics, 2017Co-Authors: Qingfeng Zeng, Artem R Oganov, Gilles FrapperAbstract:HCl is a textbook example of a polar covalent molecule, and has a wide range of industrial applications. Inspired by the discovery of unexpected stable sodium and potassium Chlorides, we performed systematic ab initio evolutionary searches for all stable compounds in the H–Cl system at pressures up to 400 GPa. Besides HCl, four new stoichiometries (H2Cl, H3Cl, H5Cl and H4Cl7) are found to be stable under pressure. Our predictions substantially differ from previous theoretical studies. We evidence a high significance of zero-point energy in determining phase stability. The newly discovered compounds display a rich variety of chemical bonding characteristics. At ambient pressure, H2, Cl2 and HCl molecular crystals are formed by weak intermolecular van der Waals interactions, and adjacent HCl molecules connect with each other to form asymmetric zigzag chains, which become symmetric under high pressure. In H5Cl, triangular H3+ cations are stabilized by electrostatic interactions with the anionic chloride network. Further increase of pressure drives H2 dimers to combine with H3+ cations to form H5+ units. We also found chlorine-based Kagome layers which are intercalated with zigzag HCl chains in H4Cl7. These findings could help to understand how varied bonding features can co-exist and evolve in one compound under extreme conditions.
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emergence of novel Hydrogen Chlorides under high pressure
arXiv: Materials Science, 2015Co-Authors: Qingfeng Zeng, Gilles Frapper, Artem R OganovAbstract:HCl, a 'textbook' example of a polar covalent molecule, is a well-known compound of Hydrogen and chlorine. Inspired by the discovery of unexpected stable stoichiometries of sodium Chlorides, we performed systematic searches for all stable compounds in the H-Cl system from ambient pressure to higher pressures up to 500 GPa using variable-composition ab initio evolutionary algorithm USPEX. We found several compounds that are stable under pressure, i.e. HCl, H$_2$Cl, H$_3$Cl, H$_5$Cl and H$_4$Cl$_7$, which display a rich variety of chemical bonding types. At ambient pressure, H$_2$, Cl$_2$ and HCl molecular crystals are formed by weak intermolecular van der Waals interactions and adjacent HCl molecules connect with each other to form asymmetric zigzag chains, which become symmetric under high pressure. In Hydrogen-rich Chlorides, H$_2$ and HCl react to form the thermodynamically stable H$_3$Cl crystalline compound in which molecular cyclic H$_3^+$ cations are stabilised by the Cl$^-$ sublattice. Increasing the amount of Hydrogen leads to stable solid-state H$_5$Cl, in which H$_2$ formally combines with H$_3^+$ to form H$_5^+$ cations. Additionally, chlorine-based Kagome layers are formed with intercalated zigzag HCl chains in chlorine-rich hydrides. These discoveries help to understand how varied bonding features can co-exist and evolve in one compound under extreme conditions.
A I Kryukov - One of the best experts on this subject based on the ideXlab platform.
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a mechanism ofphotocatalytic synthesis of chlorohydrins from olefins and peroxo complexes of titanium iv is proposed it consists of formation of radical containing complexes their reactions with olefins and decomposition of the s oxides obtained by h
1997Co-Authors: B F Minaev, A V Korzhak, A I KryukovAbstract:Under the action of light on peroxide complexes of titanium (IV) formed from TiC14 and H202 in alcoholic solutions containing olefms, a photocatalytic process of synthesis of chlorohydrin takes place [1]. This process is of interest both fundamentally and from an applied standpoint, since it occurs without the use of traditional reagents, involves the participation of unusual intermediate forms of the photocatalyst, i.e., complexes containing free radicals or ion radicals as ligands, and leads to the formation of valuable products in high yields. The present paper examines a possible mechanism of the reactions leading to the synthesis of chlorohydrins. The experiments were carried out at reduced temperature (T = 287 K) in order to completely exclude the contribution of the slow thermal reaction, which also leads to the formation of a chlorohydrin [2]. Irradiation of predegasified solutions was carried out with light of the 350-400-nm spectral range, corresponding to the charge-transfer bands of the photoreactive components peroxide complexes of titanium (IV) [1, 3]. Quantitative analysis of the reaction products, which were isolated and identified in [1, 2], was carried out by the method of gas chromatography. The quantum yields were determined with a ferrioxalate actinometer. Irradiation of solutions of peroxide complexes of titanium (PC) in both the absence and presence of olef'ms forms radical-containing complexes (RC 1) characterized by the structural fragments O~...Ti(IV)-4)--Ti(IV)...O~ or
B F Minaev - One of the best experts on this subject based on the ideXlab platform.
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a mechanism ofphotocatalytic synthesis of chlorohydrins from olefins and peroxo complexes of titanium iv is proposed it consists of formation of radical containing complexes their reactions with olefins and decomposition of the s oxides obtained by h
1997Co-Authors: B F Minaev, A V Korzhak, A I KryukovAbstract:Under the action of light on peroxide complexes of titanium (IV) formed from TiC14 and H202 in alcoholic solutions containing olefms, a photocatalytic process of synthesis of chlorohydrin takes place [1]. This process is of interest both fundamentally and from an applied standpoint, since it occurs without the use of traditional reagents, involves the participation of unusual intermediate forms of the photocatalyst, i.e., complexes containing free radicals or ion radicals as ligands, and leads to the formation of valuable products in high yields. The present paper examines a possible mechanism of the reactions leading to the synthesis of chlorohydrins. The experiments were carried out at reduced temperature (T = 287 K) in order to completely exclude the contribution of the slow thermal reaction, which also leads to the formation of a chlorohydrin [2]. Irradiation of predegasified solutions was carried out with light of the 350-400-nm spectral range, corresponding to the charge-transfer bands of the photoreactive components peroxide complexes of titanium (IV) [1, 3]. Quantitative analysis of the reaction products, which were isolated and identified in [1, 2], was carried out by the method of gas chromatography. The quantum yields were determined with a ferrioxalate actinometer. Irradiation of solutions of peroxide complexes of titanium (PC) in both the absence and presence of olef'ms forms radical-containing complexes (RC 1) characterized by the structural fragments O~...Ti(IV)-4)--Ti(IV)...O~ or
