| Abstract | High-pressure phase transition of boron triiodide (BI3) is investigated using first-principles methods, with the crystal structure of the high-pressure phase predicted. The structure is consistent with the information on this phase available from experiments. Significantly, the BI3 molecules are predicted to form B2I6 dimers that are structurally analogous to the D2h diborane molecules. Dimerization of BI3 molecules yields a notable volume drop that triggers a first-order phase transition. Using the predicted structure, the calculated equation of state, phase transition pressure, and the metallization transition pressure are in an excellent agreement with the experimental measurements. Dimerization in crystalline BI3 provides insight for the understanding of covalently bound boron halide dimers, which were previously unknown. © 2011 American Physical Society. |
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