TY - GEN
T1 - Noncentrosymmetry in mixed metal oxide-fluorides
T2 - 2008 MRS Fall Meeting
AU - Pinlac, Rachelle Ann F.
AU - Marvel, Michael R.
AU - Lesage, Julien J.M.
AU - Poeppelmeier, Kenneth R.
PY - 2008
Y1 - 2008
N2 - The rational design of crystal structures, in particular noncentrosymmetric materials, and how to differentiate polar, polar-chiral, and chiral structures, is an ongoing theme in crystal engineering. In KNaNbOF5, the combination of a second-order Jahn Teller active d0 transition metal oxyfluoride anionic unit and mixed K/Na cation coordination environments are shown to result in a polar structure (space group Pna21). The crystal structure analysis of the Na/K-O/F interactions reveals that the potassium cations form one of the two contacts to the under-bonded oxide ions. These interactions satisfy the expected bond valence sums and Pauling's second crystal rule (PSCR), leading to O/F ordering and acentric packing of the [NbOF 5]2- anionic unit.
AB - The rational design of crystal structures, in particular noncentrosymmetric materials, and how to differentiate polar, polar-chiral, and chiral structures, is an ongoing theme in crystal engineering. In KNaNbOF5, the combination of a second-order Jahn Teller active d0 transition metal oxyfluoride anionic unit and mixed K/Na cation coordination environments are shown to result in a polar structure (space group Pna21). The crystal structure analysis of the Na/K-O/F interactions reveals that the potassium cations form one of the two contacts to the under-bonded oxide ions. These interactions satisfy the expected bond valence sums and Pauling's second crystal rule (PSCR), leading to O/F ordering and acentric packing of the [NbOF 5]2- anionic unit.
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U2 - 10.1557/proc-1148-pp01-04
DO - 10.1557/proc-1148-pp01-04
M3 - Conference contribution
AN - SCOPUS:77950487313
SN - 9781615677740
T3 - Materials Research Society Symposium Proceedings
SP - 18
EP - 29
BT - Solid-State Chemistry of Inorganic Materials VII
PB - Materials Research Society
Y2 - 1 December 2008 through 2 December 2008
ER -