Question

Pyroxenes are class of silicate minerals, which exhibit a polymeric chain structure, as shown below



Its simplest repeating unit is

• A. $[Si{O}_4{]}^{4-}$
• B. $[Si{O}_3{]}^{2-}$
• C. $[S{i}_2{O}_7{]}^{6-}$
• D. $[S{i}_4{O}_{11}{]}^{6-}$

Answer 1

Answer: (B)

In pyroxenes, there is a total of 3 oxygen atoms per silicon atom, so the simplest repeating unit is ${\left[{\text{SiO}}_{\text{3}}\right]}^{\text{2}-}$ or ${\left[{\text{SiO}}_{\text{3}}\right]}_{\text{n}}^{\text{2n}-}$