TY - JOUR
T1 - Polar alignment of Λ-shaped basic building units within transition metal oxide fluoride materials
AU - Holland, Michael
AU - Donakowski, Martin D.
AU - Pozzi, Eric A.
AU - Rasmussen, Andrew M.
AU - Tran, Thanh Thao
AU - Pease-Dodson, Shannon E.
AU - Halasyamani, Paramasivan
AU - Seideman, Tamar
AU - Van Duyne, Richard P.
AU - Poeppelmeier, Kenneth R.
PY - 2014/1/6
Y1 - 2014/1/6
N2 - A series of pseudosymmetrical structures of formula K10(M 2OnF11-n)3X (M = V and Nb, n = 2, X = (F2Cl)1/3, Br, Br4/2,I4/2; M = Mo, n = 4, X = Cl, Br4/2, I4/2) illustrates generation of polar structures with the use of Λ-shaped basic building units (BBUs). For a compound to belong to a polar space group, dipole moments of individual species must be partially aligned. Incorporation of d0 early transition metal polyhedral BBUs into structures is a common method to create polar structures, owing to the second-order Jahn-Teller distortion these polyhedra contain. Less attention has been spent examining how to align the polar moments of BBUs. To address alignment, we present a study on previously reported bimetallic BBUs and synthesized compounds K10(M 2OnF11-n)3X. These materials differ in their (non)centrosymmetry despite chemical and structural similarities. The vanadium compounds are centrosymmetric (space groups P3̄m1 or C2/m) while the niobium and molybdenum heterotypes are noncentrosymmetric (Pmn2 1). The difference in symmetry occurs owing to the presence of linear, bimetallic BBUs or Λ-shaped bimetallic BBUs and related packing effects. These Λ-shaped BBUs form as a consequence of the coordination environment around the bridging anion of the metal oxide fluoride BBUs.
AB - A series of pseudosymmetrical structures of formula K10(M 2OnF11-n)3X (M = V and Nb, n = 2, X = (F2Cl)1/3, Br, Br4/2,I4/2; M = Mo, n = 4, X = Cl, Br4/2, I4/2) illustrates generation of polar structures with the use of Λ-shaped basic building units (BBUs). For a compound to belong to a polar space group, dipole moments of individual species must be partially aligned. Incorporation of d0 early transition metal polyhedral BBUs into structures is a common method to create polar structures, owing to the second-order Jahn-Teller distortion these polyhedra contain. Less attention has been spent examining how to align the polar moments of BBUs. To address alignment, we present a study on previously reported bimetallic BBUs and synthesized compounds K10(M 2OnF11-n)3X. These materials differ in their (non)centrosymmetry despite chemical and structural similarities. The vanadium compounds are centrosymmetric (space groups P3̄m1 or C2/m) while the niobium and molybdenum heterotypes are noncentrosymmetric (Pmn2 1). The difference in symmetry occurs owing to the presence of linear, bimetallic BBUs or Λ-shaped bimetallic BBUs and related packing effects. These Λ-shaped BBUs form as a consequence of the coordination environment around the bridging anion of the metal oxide fluoride BBUs.
UR - http://www.scopus.com/inward/record.url?scp=84891807091&partnerID=8YFLogxK
U2 - 10.1021/ic402177j
DO - 10.1021/ic402177j
M3 - Article
AN - SCOPUS:84891807091
VL - 53
SP - 221
EP - 228
JO - Inorganic Chemistry
JF - Inorganic Chemistry
SN - 0020-1669
IS - 1
ER -