The unstable chemical compound decomposed quickly at room temperature, forcing chemists to store it in a chilled, inert atmosphere.
这种不稳定的化合物在室温下迅速分解，迫使化学家将其储存在低温惰性环境中。
Which choice best defines “unstable”?
A — Likely to change or fail; not stable. “unstable” means likely to change or fail; not stable.
Which word means “likely to change or fail; not stable”?
A — unstable. “unstable” means likely to change or fail; not stable.
unstable — likely to change or fail; not stable. In Chinese: 不稳定的.
unstable is pronounced /ʌnˈsteɪbl/.
The unstable chemical compound decomposed quickly at room temperature, forcing chemists to store it in a chilled, inert atmosphere. (这种不稳定的化合物在室温下迅速分解，迫使化学家将其储存在低温惰性环境中。)
volatile, unsteady, precarious — all close in meaning to unstable (likely to change or fail; not stable).
stable, steady — each the opposite of unstable (likely to change or fail; not stable).
Yes. unstable is on the SAT Prep Basic list — the everyday academic words the SAT assumes you already have. The Digital SAT does not test vocabulary in isolation; words like this one are tested through Words in Context questions, where you choose the word that completes a passage most logically and precisely.