Isotopes of heavy elements are produced in various amounts by nuclear processes in stars^1,2. Consequently, the presence of isotopic anomalies in the Solar System is considered to reflect the presence of presolar grains condensed in previous generations of stars³ and not a (proto-) Solar System process. However, for oxygen, the major rock-forming element, it has been shown that physico-chemical reactions applicable to the presolar cloud or the protoplanetary disk were a possible source of isotopic variations due to mass-independent isotopic fractionation (MIF)^4,5. Here we show that MIF effects are not restricted to oxygen, but can also be produced for titanium. Titanium-rich grains experimentally condensed from a TiCl_4(g)/C₅H_12(g) plasma exhibit MIF effects from −25% to +120% for all Ti isotopic ratios. These large Ti isotopic variations follow the model developed for oxygen MIF⁶ and mimic the Ti isotopic anomalies observed in some presolar grains. This effect is ascribed to the reactions between chemically indistinguishable isotopes⁶ and could contribute to the complexity of isotopic anomalies observed in Solar System materials^{1,7,8,9,10,11,12,13,14}.

重元素的同位素通过恒星^1,2的核过程产生各种量。因此，太阳系中同位素异常的存在被认为反映了前几代恒星^3中凝结的太阳前粒子的存在，而不是（原始）太阳系过程。然而，对于氧气（主要的岩石形成元素）而言，由于质量无关的同位素分馏（MIF）^4,5，表明适用于前太阳云或原行星盘的物理化学反应是同位素变化的可能来源。在这里，我们证明MIF的作用不仅限于氧气，钛也可以产生。从TiCl _4（g） / C实验凝结的富钛晶粒对于所有Ti同位素比率，₅ H _12（g）等离子体均表现出MIF效应从-25％到+ 120％。这些较大的Ti同位素变化遵循为氧气MIF ⁶开发的模型，并模拟了在某些太阳前晶粒中观察到的Ti同位素异常。这种影响归因于化学上无法区分的同位素⁶之间的反应，并且可能导致在太阳系材料^{1,7,8,9,10,11,12,13,14中}观察到的同位素异常的复杂性。