The radius of a Na⁺ ion is 97 pm; the radius of a Cl ^- ion is 181 pm; their radius ratio is 0.54. When the ions are drawn to scale, it is difficult to see into the unit cell. Thus we will usually draw the structure with a radius ratio of about 1:1.

Many compounds crystallize with the NaCl structure including all lithium, sodium, and potassium halides and hydrides (with the formula MX) as well as many Group 2 transition metal oxides with the formula MO.

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