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crystal structure; lithium salts; tricyanomethanide [C(CN)(3)] (tcm); vibrational spectra
Abstract:
The long-elusive structure of lithium tricyanomethanide Li[C(CN)(3)] has been determined on the basis of material synthesized via a metathesis reaction of Ag[C(CN)(3)] with LiCl in water driven by AgCl precipitation and subsequently recrystallization from methanol. Li[C(CN)(3)] crystallizes in the non-centrosymmetric orthorhombic space group Ima2 with the unit-cell parameters a = 751.06(4), b = 1059.75(6) and c = 563.27(3) pm adopting a unique structure with planar [C(CN)(3)](-) anions exhibiting nearly ideal trigonal planar D-3h symmetry. The Li+ cations are coordinated by five independent tricyanomethanide anions forming a distorted square pyramid with Li-N distances between 202 and 249 pm. The vibrational frequencies were also determined and along with other properties of Li[C(CN)(3)] compared with those of related compounds.
