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Nilanjan Bhowmick AIR 3, CSIR NET (Earth Science)
Saurabh 1 Best Answer
This is purely based on radius ratio (which you can calculate easily for any type of interstitial voids be it triangular, tetrahedral Or any other types using simple trigonometry and geometry). For triangular void, radius ratio (r/R) is equal to approximately 0.155 which is equal to 3 in terms of coordination number. Here, r= radius of the minimum sphere (minimum refers to radius value) that can be kept in the respective void, such that it won't alter the complete geometry and is compatible with the atomic arrangement. R = Radius of the sphere (in black ⚫). So, answer should be 3 .