Chemistry · States of Matter - Gases, Liquids and Solids
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The coordination number of Na+ in NaCl crystal is:
- A
6
- B
2
- C
4
- D
8
The coordination number is the number of ions that immediately surround an ion of the opposite charge within a crystal lattice. If you examine the figure below, you will see that there are six chloride ions immediately surrounding a single sodium ion. The coordination number of sodium is 6.
In the NaCl crystal structure, each Na+ ion is surrounded by six Cl- ions in an octahedral geometry. Therefore, the coordination number of Na+ is 6.
This option is incorrect because a coordination number of 2 would imply a linear arrangement, which is not the case in NaCl.
This option is incorrect because a coordination number of 4 would suggest a tetrahedral arrangement, which is not present in NaCl.
This option is incorrect because a coordination number of 8 is typical for body-centered cubic structures, which NaCl does not form.
Tagged under Chemistry · States of Matter - Gases, Liquids and Solids · 2013