From the perspective of growth units, the growth mechanism of Mg2（OH）2CO3.3H2O whisker is investigated in this paper. Results show that the growth morphology of Mg2（OH）2CO33H2O whisker is consistent with the model...From the perspective of growth units, the growth mechanism of Mg2（OH）2CO3.3H2O whisker is investigated in this paper. Results show that the growth morphology of Mg2（OH）2CO33H2O whisker is consistent with the model of anion coordination polyhedron growth units. The growth solution Raman shift of Mg2（OH）2CO;3H2O was monitored using Raman spectroscopy. The growth units are [Mg-（OH）4]2- and H2COv The growth process of Mg2（OH）2COf3H2O whisker is as follows： growth unit [Mg-（OH）4]2- first incorporates into the larger dimension [Mg-（OH）4]2-, then the [Mg-（OH）4]2-n combines with H2CO3 into a linear skeleton Mg2（OH）2CO3 in the same line. Mg2（OH）2CO3 combines with H2O by hydrogen bonds and ultimately transforms into Mg2（OH）2COf3H2O whisker. Magnesium carbonate whiskers have a layered structure, each of which is made of magnesium, carbon, oxygen, with H2O in between each layer. When skeletons are superimposed within the same plane as a parallelepiped one, they grow into solid cuboid-shaped whiskers. When the parallelepiped skeletons planes combine with each other through the cascading links, they grow into hollow cylindrical whiskers.展开更多
From the point of growth units, the growth mechanism of hydrotalcite (HT) crystal is investigated in this paper. Results show that the growth morphology of HT is consistent with the model of anion coordination polyhed...From the point of growth units, the growth mechanism of hydrotalcite (HT) crystal is investigated in this paper. Results show that the growth morphology of HT is consistent with the model of anion coordination polyhedron growth units. The Raman shift of growth solutions of HT, Cu-HTlc, and Cu-Zn-HTlc are monitored using Raman spectroscopy. In the experiment, the growth units of Mg-Al-hydrotalcite are [Mg-(OH)6]4- and [Al-(OH)6]3-, and the growth units of Cu-Htlc and Cu-Zn-HTlc are [Mg-(OH)6]4- and [Al-(OH)6]3-, respectively. The growth process of hydrotalcite is as follows: growth units first incorpo- rate into metal layers, then metal layers adsorb An- and H2O, and the growth units incorporate into layer compounds according to this rule. Growth units will have different incorporations and growth morphologies caused by different growth surroundings. Furthermore, the reason why Cu-HTlc is difficult to synthesize is also interpreted in this paper.展开更多
The growth units and formation mechanisms of quartz(SiO_2)and barium titanate (BaTiO_3)crystals under hydrothermal conditions have been investigated by means of cataphoretic experi- ments.It is proposed that the growt...The growth units and formation mechanisms of quartz(SiO_2)and barium titanate (BaTiO_3)crystals under hydrothermal conditions have been investigated by means of cataphoretic experi- ments.It is proposed that the growth units of the crystals in hydrothermal solutions have the structures of coordinative polyhedra of anions,which correspond to those of coordinative polyhedra in the crystals. The relationship between crystal morphology and physico-chemical conditions has been explained accord- ing to the modes of incorporation of the coordinative polyhedra of anions on the various faces of crystals. The dimensions of the growth units vary with the change of the growth condition.The incorporation rates on the various faces of the growth units with varied dimensions must be different,which leads to a satis- factory explanation for the variety of the crystal morphology.展开更多
The growth habit of the basic magnesium oxysulfate whisker was investigated based on the theoreticalmodelof anion coordination polyhedron growth units.It is found that typicalbasic magnesium oxysulfate whisker growth ...The growth habit of the basic magnesium oxysulfate whisker was investigated based on the theoreticalmodelof anion coordination polyhedron growth units.It is found that typicalbasic magnesium oxysulfate whisker growth is consistent with anion tetrahedralcoordination incorporation rules.The growth units of basic magnesium oxysulfate whiskers are [Mg-（OH）_4]^（2-） and HSO_4^-.[Mg-（OH）_4]^（2-） is the favorable growth unit and whisker growth is in the direction of the [Mg-（OH）_4]^（2-） combination.A plurality of [Mg-（OH）_4]^（2-） s combine and become a larger dimensionalgrowth unit in a one-dimensionaldirection.Then HSO_4^- and larger dimensionalgrowth units connect as basic magnesium sulfate whiskers,according to the structuralcharacteristics of the basic magnesium sulfate whisker,which can guide the synthesis of magnesium hydroxide whisker.展开更多
基金Funded by the National Natural Science Foundation of China(No.51272207)
文摘From the perspective of growth units, the growth mechanism of Mg2（OH）2CO3.3H2O whisker is investigated in this paper. Results show that the growth morphology of Mg2（OH）2CO33H2O whisker is consistent with the model of anion coordination polyhedron growth units. The growth solution Raman shift of Mg2（OH）2CO;3H2O was monitored using Raman spectroscopy. The growth units are [Mg-（OH）4]2- and H2COv The growth process of Mg2（OH）2COf3H2O whisker is as follows： growth unit [Mg-（OH）4]2- first incorporates into the larger dimension [Mg-（OH）4]2-, then the [Mg-（OH）4]2-n combines with H2CO3 into a linear skeleton Mg2（OH）2CO3 in the same line. Mg2（OH）2CO3 combines with H2O by hydrogen bonds and ultimately transforms into Mg2（OH）2COf3H2O whisker. Magnesium carbonate whiskers have a layered structure, each of which is made of magnesium, carbon, oxygen, with H2O in between each layer. When skeletons are superimposed within the same plane as a parallelepiped one, they grow into solid cuboid-shaped whiskers. When the parallelepiped skeletons planes combine with each other through the cascading links, they grow into hollow cylindrical whiskers.
基金supported by the National Natural Science Foundation of China (Grant Nos.40776071,40976074)
文摘From the point of growth units, the growth mechanism of hydrotalcite (HT) crystal is investigated in this paper. Results show that the growth morphology of HT is consistent with the model of anion coordination polyhedron growth units. The Raman shift of growth solutions of HT, Cu-HTlc, and Cu-Zn-HTlc are monitored using Raman spectroscopy. In the experiment, the growth units of Mg-Al-hydrotalcite are [Mg-(OH)6]4- and [Al-(OH)6]3-, and the growth units of Cu-Htlc and Cu-Zn-HTlc are [Mg-(OH)6]4- and [Al-(OH)6]3-, respectively. The growth process of hydrotalcite is as follows: growth units first incorpo- rate into metal layers, then metal layers adsorb An- and H2O, and the growth units incorporate into layer compounds according to this rule. Growth units will have different incorporations and growth morphologies caused by different growth surroundings. Furthermore, the reason why Cu-HTlc is difficult to synthesize is also interpreted in this paper.
基金the key research project in Climbing Program from the State Science and Technology Commission of China
文摘The growth units and formation mechanisms of quartz(SiO_2)and barium titanate (BaTiO_3)crystals under hydrothermal conditions have been investigated by means of cataphoretic experi- ments.It is proposed that the growth units of the crystals in hydrothermal solutions have the structures of coordinative polyhedra of anions,which correspond to those of coordinative polyhedra in the crystals. The relationship between crystal morphology and physico-chemical conditions has been explained accord- ing to the modes of incorporation of the coordinative polyhedra of anions on the various faces of crystals. The dimensions of the growth units vary with the change of the growth condition.The incorporation rates on the various faces of the growth units with varied dimensions must be different,which leads to a satis- factory explanation for the variety of the crystal morphology.
基金Funded by the National Natural Science Foundation of China(No.51272207)
文摘The growth habit of the basic magnesium oxysulfate whisker was investigated based on the theoreticalmodelof anion coordination polyhedron growth units.It is found that typicalbasic magnesium oxysulfate whisker growth is consistent with anion tetrahedralcoordination incorporation rules.The growth units of basic magnesium oxysulfate whiskers are [Mg-（OH）_4]^（2-） and HSO_4^-.[Mg-（OH）_4]^（2-） is the favorable growth unit and whisker growth is in the direction of the [Mg-（OH）_4]^（2-） combination.A plurality of [Mg-（OH）_4]^（2-） s combine and become a larger dimensionalgrowth unit in a one-dimensionaldirection.Then HSO_4^- and larger dimensionalgrowth units connect as basic magnesium sulfate whiskers,according to the structuralcharacteristics of the basic magnesium sulfate whisker,which can guide the synthesis of magnesium hydroxide whisker.
