TY - JOUR
T1 - Periodic Tendril Perversion and Helices in the AMoO2F3 (A = K, Rb, NH4, Tl) Family
AU - Hancock, Justin C.
AU - Nisbet, Matthew L.
AU - Zhang, Weiguo
AU - Halasyamani, P. Shiv
AU - Poeppelmeier, Kenneth R.
N1 - Funding Information:
The authors thank Charlotte Stern for helpful discussions regarding the reported crystal structures. This work was supported by the Joint Center for Energy Storage Research (JCESR), an Energy Innovation Hub funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences (J.C.H. and K.R.P.). This work was also supported by funding from the National Science Foundation under grant DMR-1904701 (M.L.N.). The single-crystal X-ray data measurements were acquired at Northwestern University’s Integrated Molecular Structure Education and Research Center (IMSERC) at Northwestern University, which is supported by grants from NSF-NSEC, NSF-MRSEC, the KECK Foundation, the State of Illinois, and Northwestern University. P.S.H. and W.Z. thank the Welch Foundation (Grant E-1457) for support.
Publisher Copyright:
Copyright © 2020 American Chemical Society.
PY - 2020/4/1
Y1 - 2020/4/1
N2 - Although compounds of the formula AMoO2F3 (A = K, Rb, Cs, NH4, Tl) have been known for decades, crystal structures have only been reported for CsMoO2F3 and NH4MoO2F3. The three compounds (Rb/NH4/Tl)MoO2F3 are isostructural and crystallize in the centrosymmetric space group C2/c (No. 15). The compounds contain the MoO2F3- anionic chain, composed of corner-sharing MoO2F4 octahedra, with Mo6+ coordinated by two cis bridging fluoride anions that are trans to terminal oxide anions. The MoO2F3- chain has a very unusual and complex chain structure; a single chain contains alternating zigzag and helical sections. These helical regions alternate in chirality along the chain, and thus the chains exhibit periodic tendril perversion. To the best of the authors' knowledge, no other materials with a similar chain structure have been reported. On the other hand, KMoO2F3 is noncentrosymmetric and chiral, crystallizing in the enantiomorphic space group P212121 (No. 19). KMoO2F3 also contains the MoO2F3- anionic chain. However, the chain is helical, with only one enantiomer present, resulting in a chiral, noncentrosymmetric structure.
AB - Although compounds of the formula AMoO2F3 (A = K, Rb, Cs, NH4, Tl) have been known for decades, crystal structures have only been reported for CsMoO2F3 and NH4MoO2F3. The three compounds (Rb/NH4/Tl)MoO2F3 are isostructural and crystallize in the centrosymmetric space group C2/c (No. 15). The compounds contain the MoO2F3- anionic chain, composed of corner-sharing MoO2F4 octahedra, with Mo6+ coordinated by two cis bridging fluoride anions that are trans to terminal oxide anions. The MoO2F3- chain has a very unusual and complex chain structure; a single chain contains alternating zigzag and helical sections. These helical regions alternate in chirality along the chain, and thus the chains exhibit periodic tendril perversion. To the best of the authors' knowledge, no other materials with a similar chain structure have been reported. On the other hand, KMoO2F3 is noncentrosymmetric and chiral, crystallizing in the enantiomorphic space group P212121 (No. 19). KMoO2F3 also contains the MoO2F3- anionic chain. However, the chain is helical, with only one enantiomer present, resulting in a chiral, noncentrosymmetric structure.
UR - http://www.scopus.com/inward/record.url?scp=85083633749&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85083633749&partnerID=8YFLogxK
U2 - 10.1021/jacs.0c01218
DO - 10.1021/jacs.0c01218
M3 - Article
C2 - 32160458
AN - SCOPUS:85083633749
VL - 142
SP - 6375
EP - 6380
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
SN - 0002-7863
IS - 13
ER -