Atoms and ions have a certain effective radius, which can be seen as a certain size of the sphere. Metal ions in the crystal and the crystal, metal bond and the ionic bond-directional and saturation. Therefore, from the geometric point of view, between the metal atoms or particles with each other, in the form of a sphere can be seen as inter-accumulation. With minimum internal energy of the crystal, atoms and ions combined with each other, the mutual attraction and repulsion in balance, which is equivalent to a sphere required to do between the closely packed! 1, and other large ball room (common in metal crystals) to do only one form of closest packing, that is our common hexagonal close-packed; 2, ranging from large sphere close packing to do, it can be seen as a large sphere into a way of accumulation of such big balls, small balls the size of their own to fill the octahedral or tetrahedral voids, which more common in ionic crystals such as sodium chloride.
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No. 2
密堆积结构
密堆积结构
Atoms and ions have a certain effective radius, which can be seen as a certain size of the sphere. Metal ions in the crystal and the crystal, metal bond and the ionic bond-directional and saturation. Therefore, from the geometric point of view, between the metal atoms or particles with each other, in the form of a sphere can be seen as inter-accumulation. With minimum internal energy of the crystal, atoms and ions combined with each other, the mutual attraction and repulsion in balance, which is equivalent to a sphere required to do between the closely packed! 1, the metal atoms in the crystal stacking modes common are: hexagonal close-packed (hcp) (also known as the accumulation of Mg-based), face-centered cubic close packing (ccp) (also known as Cu-accumulation), accumulation of body-centered cubic bcc) ( also known as K-type deposits), in which close-packed face-centered cubic and hexagonal close-packed cubic space utilization up to 74%, while the accumulation of body-centered cubic space utilization rate is only 68% 2, ranging from large sphere close packing to do, it can be seen as a large sphere into a way of accumulation of such big balls, small balls the size of their own to fill the octahedral or tetrahedral voids, which more common in ionic crystals such as sodium chloride. Crystal atoms (or ions) in the absence of other factors (such as bond direction, alternately positive and negative ions, etc.) under the influence, the attraction between each other as close as possible to form close-packed arrangement of space the stability of the structure. Space density with the accumulation of space utilization (the total volume of atoms within the unit cell volume percentage of total cell) said. The ions (usually metal ions) such as approximate diameter of just the ball, the plane graph in Figure 1 in the close-packed arrangement as shown in A ball. The gap ball B and C have two. In the row of the second layer to be put the ball B (or C) bit to get the most close accumulation. But ranked third layer, the second layer to form a ball gap may be A or C (for the second layer for the B-bit), so as to place the location of the ball, there are two different close-packed structure. ① cubic close packing. The third layer of the ball into the C bit, the fourth layer of the ball into the gap formed by the third layer of the ball at A, and the law repeatedly by ABCABC ... accumulation continues, as shown in Figure 2a. Face-centered cubic (111) stacked along [111] direction is the case, the metal Cu, Al, Au and other structures belonging to this structure. ② hexagonal close packing. A third layer of the ball into the bit, and go by ABABAB ... order accumulation (Figure 2b). When the hexagonal axis than с / a = 1.633, its (0001) [0001] direction along the surface accumulation of the situation is the case. Metals Zn, Mg, Be, etc. belong to this structure. Two kinds of close-packed structures are 74% space utilization
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百科 Daquan
miduiji jiegou Close-packed structure close-packed structure Crystal atoms (or ions) in the absence of other factors (such as bond direction, alternately positive and negative ions, etc.) under the influence, the attraction between each other as close as possible to form close-packed arrangement of space the stability of the structure. Space density with the accumulation of space utilization (the total volume of atoms within the unit cell volume percentage of total cell) said. The ions (usually metal ions) such as approximate diameter of just the ball, the plane close-packed close-packed plane graph in Figure 1 and the gap layer arrangement shown in A ball. The gap ball B and C have two. In the row of the second layer to be put the ball B (or C) bit to get the most close accumulation. But ranked third layer, the second layer to form a ball gap may be A or C (for the second layer for the B-bit), so as to place the location of the ball, there are two different close-packed structure. ① cubic close packing. The third layer of the ball into the C bit, the fourth layer of the ball into the gap formed by the third layer of the ball at A, and the law repeatedly by ABCABC ... accumulation continues, as shown in Figure 2a the difference between two kinds of close-packed structure is shown. Face-centered cubic (111) surface along the direction of accumulation is the case, the metal Cu, Al, Au and other structures belonging to this structure. ② hexagonal close packing. A third layer of the ball into the bit, and go by ABABAB ... order accumulation (Figure 2b two kinds of close-packed structure of the difference). When the hexagonal axis than □ / □ = 1.633 when the (0001) surface along the direction of the buildup to the case. Metals Zn, Mg, Be, etc. belong to this structure. Two kinds of close-packed structure of the space utilization are □ (Tang Disheng)
