[mokiph]

someone to kindly help me with this question. i have manged part (a) and i cant figure out the part be of the question

 Beta crystoballite is having a three dimensional crystalline structure. if the radii of the cation and anion are 0.41 and 1.40 respectively;
a) which crystal structure does it belong to?
b) if a cation is surrounded by four cations and an anion is surrounded by only two anions giving a 4:2 coordination, represent the crystal using it simplest formula.

(mod edit title to something a bit more useful, was _HELP NEEDED_)

[sjb]

someone to kindly help me with this question. i have manged part (a) and i cant figure out the part be of the question

 Beta crystoballite is having a three dimensional crystalline structure. if the radii of the cation and anion are 0.41 and 1.40 respectively;
a) which crystal structure does it belong to?
b) if a cation is surrounded by four cations and an anion is surrounded by only two anions giving a 4:2 coordination, represent the crystal using it simplest formula.

So, what do you have for part a)? What are your thoughts?