Which of the following statements about the elements, Mg, Ca, Sr and Ba and their compounds is true?

Options

A. a) `Na_(2)O, phi=(pi)/(3sqrt(2)) {1+2xx(0.225)^(3)}`
B. b) `Cr_(2)O_(3),phi=(pi)/(3sqrt(2)){1+ 2/3xx(0.414)^(3)}`
C. c) `Fe_(2), O_(3), phi=(pi)/(3sqrt(2)){1+(0.225)^(3)}`
D. d) Diamond, `phi=(pi)/(3sqrt(2)){1+(0.414)^(3)}`

Answer

A, B

Explanation

`Fe_(2)O_(3), phi=(pi)/(3sqrt(2)){1+2/3(0.414)^(3)}`
Diamond `phi=8xx(4pir^(3))/(3xx(2sqrt(2)R)^(3))`