Determinants of crystal structure transformation of ionic nanocrystals in cation exchange reactions.
basic_science · Level V
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- Record sourced from PubMed, PMID 34437152.
- Also identified by DOI 10.1126/science.abh2741.
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Abstract
Changes in the crystal system of an ionic nanocrystal during a cation exchange reaction are unusual yet remain to be systematically investigated. In this study, chemical synthesis and computational modeling demonstrated that the height of hexagonal-prism roxbyite (Cu<sub>1.8</sub>S) nanocrystals with a distorted hexagonal close-packed sulfide anion (S<sup>2-</sup>) sublattice determines the final crystal phase of the cation-exchanged products with Co<sup>2+</sup> [wurtzite cobalt sulfide (CoS) with hexagonal close-packed S<sup>2-</sup> and/or cobalt pentlandite (Co<sub>9</sub>S<sub>8</sub>) with cubic close-packed S<sup>2-</sup>]. Thermodynamic instability of exposed planes drives reconstruction of anion frameworks under mild reaction conditions. Other incoming cations (Mn<sup>2+</sup>, Zn<sup>2+</sup>, and Ni<sup>2+</sup>) modulate crystal structure transformation during cation exchange reactions by various means, such as volume, thermodynamic stability, and coordination environment.