0 The change in coordination number of silicon (Si) when o-quartz transforms to stishovite, which has octahedral coordination, is (B) 4 (A) 2 (C) 6 (D) 8
Correct answer would be 2... As the coordination number of stishovite is 6 while that of alpha quartz(or other quartz polymorph) is 4. So difference (6-4=2) ...
The coordination number of stishovite is 6, so the silicon atoms are all surrounded by 6 oxygen atoms. The crystal structure of stishovite does not fit in the classification scheme...