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Draw a neat diagram of sodium chloride structure and then describe it. |
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Answer» Solution :The structure of NaCl is as shown below. In this case, the `Cl^(-)` ions from the cubic CLOSE PACKED arrangements. Therefore,`Cl^(-)`ions are present at all the corners and the centre of each face of the cube. The ARRANGEMENT is also regarded as face centred cubic arrangement of `Cl^(-)` ions. The `Na^(+)` ions occupy all the octahedral SITES. As we know that there is one octahedral site per atom in a close packed arrangement, therefore, there will be one`Na^(+)` ion for every `Cl^(-)` ion. Thus, the ratio of `Na^(+)` and `Cl^(-)` ions in this structure is 1:1.  In this structure, each `Na^(+)` ion is surrounded by 6 `Cl^(-)` ions which are disposed towards the corners REGULAR octahedron. This is also shown in the figure. Similarly, each `Cl^(-)` ion is surrounded by six `Na^(+)` ions. Thus, the coordination number of `Na^(+)` and `Cl^(-)` ions in NaCl structure is 6 and 6. |
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