二茂铑（英语：Rhodocene），也称双（η-环戊二烯基）合铑（II），分子式为[Rh(C₅H₅)₂]。分子由两个η的环戊二烯配体（哈普托数为5，表示环戊二烯基有五个原子参与配位）和一个铑原子构成，铑原子处在平行的两个环戊二烯基中间形成“三明治”夹心结构。由于二茂铑的价电子数为19，根据18电子规则判断它在室温下是不稳定的并且具有类似自由基的性质。实验获得的事实也已经证实了这点。二茂铑能存在于大于150°C的温度下，可利用液氮(−196°C)急速冷却的方法捕获到它。室温下，两个二茂铑分子的环戊二烯基会键合形成黄色的二聚体。

Rhodocene, formally known as bis(η-cyclopentadienyl)rhodium(II), is a chemical compound with the formula [Rh(C₅H₅)₂]. Each molecule contains an atom of rhodium bound between two planar systems of five carbon atoms known as cyclopentadienyl rings in a sandwich arrangement. It is an organometallic compound as it has (haptic) covalent rhodium–carbon bonds. The [Rh(C₅H₅)₂] radical is found above 150 °C or when trapped by cooling to liquid nitrogen temperatures (−196 °C). At room temperature, pairs of these radicals combine to form a dimer, a yellow solid in which two of these cyclopentadienyl rings are joined.