Cadmium $($At$.$ Wt$.=112\mathrm{.}41$ g$/$mol$)$ has an HCP crystal structure and a density of $8\mathrm{.}65$ g$/$cm$3.($i$)$ What is the volume of its unit cell in cubic meters? $($ii$)$ If the c$/$a ratio is $1\mathrm{.}593,$ compute the values of c and a$.$