The interaction of wollastonite (CaSiO3), a silicate mineral, with CO2 and water is highly relevant in the field of carbon capture [1], rock weathering [2] and cement production [3]. We have investigated the preferentially cleaved (100) surface in ultrahigh vacuum (UHV) and exposed it to controlled amounts of H2O and CO2 at 100 K. Using non-contact atomic force microscopy (NC-AFM) with functionalised tips, combined with ab-initio density functional theory (DFT) and AFM-simulations [4], we determined the atomic structure of the cleaved surfaces and the adsorption configurations of H2O and CO2. The cleaved surface exposes rows of alternating calcium and oxygen atoms. Between these rows, water adsorbs molecularly and without a barrier in a nested position, which was not reported in previous literature. The nested H2O molecule aids the adsorption of the CO2, which in turn forms a carbonate-like structure due to its interaction with the surface. At higher coverage, the strongly bound water forms regular patterns. [1] W. J.J. Huijgen, et al. Chem. Eng. Sci. 61, 4242 (2006). [2] D. Feng, et al. J. Clean. Prod., 414, 137625 (2023). [3] H. Huang, et al. J. Clean. Prod., 211, 830 (2019). [4] N. Oinonen, et al. Comput. Phys. Commun., 305, 109341 (2024).