Compound FB(BF₂)₂ disproportionates at –30 °C to give BF₃ and very unstable B₈F₁₂. The B₈F₁₂ molecule is unstable because it contains a strained four-membered ring of boron atoms. Write a balanced chemical equation for this process, and draw a plausible structure for B₈F₁₂. The B₈F₁₂ contains six BF₂ units, only two of which are part of the four-membered ring.