I think it might be Nitrogen dioxide, but please check behind
Molar mass Cu(OH)₂ = 97.561 g/mol
97.561 g Cu(OH)₂ --------------- 6.02x10²³ atoms
? g Cu(OH)₂ -------------------- 9.1x10²⁵ atoms
mass = 9.1x10²⁵ * 97.561 / 6.02x10²³
mass = 8.87x10²⁷ / 6.02x10²³
mass = 14734.2 g
hope this helps!
Y : CCP : 4 atoms
X : tetrahedral voids would be 1/3 × 8 = 8/3
so formula would be Y12X8 or Y3X2 !!