The following figure shows the unit cell of a compound, i.e., a mixed oxide of yttrium, barium, and copper. The formula of mixed oxide is . Find the value of

(13)

Single unit cell consist of three cubes

Number of  ions  per unit cell

Number of   ions =1 per unit cell

Number of  ions = 8 in each cube at corners)

 (in three cubes)  (per corner share)

unit cell

Number of  ions  (at edge center of cube 1) + 8 (at edge center of cube 2) + 10 (at edge center of cube 3)

 (edge center)  (per edge center share)

/unit cell

Formula: