indexcompound

例句：

1. 1. The compound's molecular structure is complex and difficult to understand.
   这种化合物的分子结构复杂且难以理解。
2. 2. The index compound was used in the early experiments to identify the chemical properties of the substance.
   这种索引化合物在早期的实验中被用来识别物质的化学性质。
3. 3. The compound has been studied extensively for its potential applications in drug discovery.
   这种化合物已被广泛研究，以探索其在药物发现中的可能应用。