60 EXPERIMENT9 Crystal Structure E. CLOSEST PACKING OF EQUAL SIZED SPHERES Figur
ID: 2036805 • Letter: 6
Question
60 EXPERIMENT9 Crystal Structure E. CLOSEST PACKING OF EQUAL SIZED SPHERES Figure st eod layer like that in Figure s (bl. Sundwich one of the hesgonal liyers shown 5 (a) between two triangular layers in such a way that the two triangular layers have the same with the one you built in Part D; is this an orientation, as shown in Figure& Now compare this model alternative form of the hexagonal closest packed structure Figure 7. Hexagonal closest packing (hcpl of spheres Reverse the orientation of one of the triangular layers as shown in Figure&. View thi angles and cubic structure: This of s model at various compare it with the model you built in Part C. Is this an alternative view of the face-centered s type of packing of spheres is ofen called cubic closest packing and is, as you have seen, identical with the packing in a face-centered cubic seructure. ?? Figure s. Cubic closest packing (ccpl of spheres What is the coordination number of a sphere in a hexagonal closest packed stracture? In a cubic close packed (or face-centered cubic) structure! How do the coordination numbers in these two structures compare? E-1. How do the fractions of space occupied by the spheres compare for the hexagonal closest packed and the cubic closest packed structures? E-2. E-3. Is it possible to pack spheres more densely than in these two structures! Explain in terms of your observations on the models you built coresponding to Figure 7 and s.Explanation / Answer
E-1)the coordination number is defined as the number of atoms present neighbour to the central atom in a molecule or crystal.
The hexagonal closest packed structure(hcp) has coordination number 12. The cubic close packed structure(ccp) (or face centered cubic(fcc)) has coordination number 12.
therefore the coordination number of hcp and ccp or fcc are same.
E-2) fraction of space occupied by spheres = total volume of spheres present in the unit cell total volume of unit cell
fraction of space occupied by spheres in hexagonal closest packing is 0.74
fraction of space occupied by spheres in hexagonal closest packing is 0.74
therefore the fraction of space occupied by spheres in hcp and ccp or fcc are same
E-3) it is not possible to pack spheres more densely then in these two structures
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.