方解石被认为是最重要的环境矿物之一，在调节水环境质量和控制重金属的迁移和转化方面发挥着重要作用。该文通过实验合成了一系列方解石—菱锶矿“异型”固溶体[(Ca1-xSrx)CO₃]（含Sr方解石型固溶体、含Ca菱锶矿型固溶体及其混合物），并在25 ℃条件下对其在初始CO₂饱和水中的溶解进行了实验研究。在含Sr方解石型固溶体溶解时，水溶液Sr/(Ca+Sr)摩尔比（X_Sr2+,aq）明显高于固相的Sr/(Ca+Sr)摩尔比（X_SrCO3），而在含Ca菱锶矿型固溶体溶解时，水溶液X_Sr2+,aq明显低于固相的X_SrCO3。稳定状态下，方解石[CaCO₃]和菱锶矿[SrCO₃]的log IAP平均值（≈log Ksp）分别为（-8.45±0.13）~（-8.42±0.11）和（-8.79±0.04）~（-8.77±0.02）。对于方解石型固溶体，随着固相X_SrCO3的增加，稳定状态下的log IAP值增加；而对于菱锶矿型固溶体，稳定状态下的log IAP值则随固相X_SrCO3的增加而减小。方解石型固溶体的X_SrCO3值最高为0.042，菱锶矿型固溶体的X_SrCO3值最低为0.609；对于方解石—菱锶矿“异型”固溶体，相应的Guggenheim参数为a0=1.62和a1=-1.46。在构建的Lippmann图中，对于X_SrCO3相对较低的含Sr方解石型固溶体，相对贫Ca水溶液最终与相对富Ca的方解石型固溶体达到平衡；对于X_SrCO3相对较高的含Ca菱锶矿型固溶体，相对贫Sr水溶液最终与相对富Sr的菱锶矿型固溶体达到平衡。方解石中的Sr、菱锶矿中Ca的置换会降低固溶体在水中的稳定性。研究结果为方解石—菱锶矿固溶体在水溶液中的稳定性提供了长期溶解实验的证据，拓展了对锶环境地球化学循环的认识。

Calcite is considered one of the most important minerals relevant to environment, and plays an important role in regulating water quality and controlling the migration and transformation of heavy metals. A range of calcite-strontianite “heterotype” solid solutions [(Ca1-xSrx)CO₃] (Sr-substituted calcites, Ca-substituted strontianites and their mixtures) with the bulk solid Sr/(Ca+Sr) mol ratios (X_SrCO3) of 0.00-1.00 were synthesized and their dissolution in initially-CO₂-saturated water for one year was experimentally studied at 25 ℃ . The aqueous Sr/(Ca+Sr) mol ratios (X_Sr2+,aq) were considerably higher than the solid X_SrCO3 values for dissolution of the Sr-calcites, and considerably lower than the solid X_SrCO3 values for dissolution of the Ca-strontianites. The mean values of log IAP at the steady state (≈log Ksp) were calculated to be (-8.45±0.13)-(-8.42±0.11) and (-8.79±0.04) - (-8.77±0.02) for calcite [CaCO₃] and strontianite [SrCO₃], respectively. In terms of the Sr-calcites, the log IAP values at the final constant state increased with the increasing X_SrCO3 of the solids; while decreased with the increasing X_SrCO3 of the solids in terms of the Ca-strontianites. The highest X_SrCO3 value in the calcite-type solid solutions and the lowest X_SrCO3 value in the strontianite-type solid solutions were measured to be 0.042 and 0.609, respectively. The corresponding dimensionless Guggenheim parameters were estimated to be a0=1.62 and a1=-1.46 for the calcite-strontianite“heterotype”solid solutions. In the constructed Lippmann diagrams, for the Sr-bearing calcite-type solid solutions with a low X_SrCO3, the Ca-poorer aqueous solutions were at equilibrium with the Ca-richer calcite-type solids; for the Ca-bearing strontianite-type solid solutions with a higher X_SrCO3, the Sr-poorer aqueous solutions were at equilibrium with the Sr-richer strontianite-type solids. The replacement of small amount of Sr in calcite and Ca in strontianite would decrease the stability of the solids. The results provide experimental evidence for the stability of calcite-strontianite solid solutions in aqueous solution and improve the understanding of the geochemical cycle of strontium in the environment.