Test analysis: According to the crystal structure of sodium chloride, there are six nearest Cl-s for each Na+ equidistance in the sodium chloride crystal, and the closed space configuration is octahedron, and the answer is C.
Comments: This question is a common question in the college entrance examination and belongs to the examination of basic questions. The examination questions are very basic, focusing on the examination and training of the basic knowledge of teaching materials, which is conducive to mobilizing students' enthusiasm for learning. The key to this problem is to remember the structural characteristics of common crystals, which is conducive to cultivating students' logical reasoning ability and abstract thinking ability.