Ultrasound is known to promote crystal nucleation, but despite significant research there remains uncertainty about how the mechanisms are affected. Despite the proposal of various primary nucleation theories, most studies provide no way to quantify or observe the extent to which primary nucleation is taking place, leaving open the possibility that sonocrystallisation is occurring by a secondary nucleation-driven mechanism. By utilising the widely reported enantiomeric properties of sodium chlorate, the extent to which ultrasound can induce primary nucleation can clearly be observed. It was demonstrated during seeded cooling crystallisation that when stirring the seed similarity was 99.3% on average, indicating secondary nucleation had almost exclusively taken place. The application of ultrasound however, decreased the seed similarity to 85.8% and 92.4% when applying 98 kHz and 200 kHz ultrasound respectively, clearly showing that primary nucleation had been induced and indicating the frequency dependency of the induced primary nucleation. This frequency dependency suggests a link between crystal nucleation and high intensity cavitation collisions and collapses, and the potential existence of a collapse/collision intensity threshold required to induce primary nucleation. In addition, secondary nucleation rate was investigated using anti-solvent crystallisation and was observed to increase with the application of ultrasound, though it appeared frequency independent (between 98 kHz & 200 kHz), suggesting that higher energy cavitational events are less important in inducing secondary nucleation or that a lower cavitation intensity threshold exists compared to primary nucleation.

众所周知，超声波可促进晶体成核，但尽管进行了大量研究，但关于其机制如何受到影响仍存在不确定性。尽管提出了各种初级成核理论，但大多数研究都没有提供量化或观察初级成核发生程度的方法，从而留下了通过次级成核驱动机制发生声结晶的可能性。通过利用广泛报道的氯酸钠的对映体特性，可以清楚地观察到超声诱导初级成核的程度。在晶种冷却结晶过程中证明，当搅拌时，晶种相似度平均为 99.3%，表明几乎完全发生了二次成核。然而，超声波的应用将种子相似度降低到 85。分别应用 98 kHz 和 200 kHz 超声时分别为 8% 和 92.4%，清楚地表明已经诱导了初级成核，并表明了诱导初级成核的频率依赖性。这种频率依赖性表明晶体成核与高强度空化碰撞和坍塌之间存在联系，以及诱导初级成核所需的坍塌/碰撞强度阈值的潜在存在。此外，使用反溶剂结晶研究了二次成核率，并观察到随着超声波的应用而增加，尽管它似乎与频率无关（在 98 kHz 和 200 kHz 之间），这表明更高能量的空化事件在诱导二次成核中不太重要成核或与初级成核相比存在较低的空化强度阈值。分别应用 98 kHz 和 200 kHz 超声时为 4%，清楚地表明已诱导初级成核并表明诱导初级成核的频率依赖性。这种频率依赖性表明晶体成核与高强度空化碰撞和坍塌之间存在联系，以及诱导初级成核所需的坍塌/碰撞强度阈值的潜在存在。此外，使用反溶剂结晶研究了二次成核率，并观察到随着超声波的应用而增加，尽管它似乎与频率无关（在 98 kHz 和 200 kHz 之间），这表明更高能量的空化事件在诱导二次成核方面不太重要成核或与初级成核相比存在较低的空化强度阈值。分别应用 98 kHz 和 200 kHz 超声时为 4%，清楚地表明已诱导初级成核并表明诱导初级成核的频率依赖性。这种频率依赖性表明晶体成核与高强度空化碰撞和坍塌之间存在联系，以及诱导初级成核所需的坍塌/碰撞强度阈值的潜在存在。此外，使用反溶剂结晶研究了二次成核率，并观察到随着超声波的应用而增加，尽管它似乎与频率无关（在 98 kHz 和 200 kHz 之间），这表明更高能量的空化事件在诱导二次成核中不太重要成核或与初级成核相比存在较低的空化强度阈值。