TY  - JOUR
AU  - Grzechnik, A.
AU  - Friese, K.
TI  - Crystal structures and stability of NaLnF4 (Ln = La, Ce, Pr, Nd, Sm and Gd) studied with synchrotron single-crystal and powder diffraction
JO  - Dalton transactions
VL  - 41
SN  - 1477-9226
CY  - London
PB  - Soc.
M1  - PreJuSER-111852
SP  - 10258 - 10266
PY  - 2012
N1  - Record converted from VDB: 16.11.2012
AB  - Crystal structures of the NaLnF(4) materials (Ln = La, Ce, Pr, Nd, Sm or Gd) were studied with synchrotron single-crystal and powder diffraction. The materials with Ln = La, Ce, Nd, Sm and Gd have the average β structure (P6, Z = 1) with partial ordering of the cations. A new type of a superstructure due to ordering of the cations and vacancies was found in NaPrF(4) (P3, Z = 6). It could be described using the group-subgroup relationships P6↔P3. Our observations suggest that the β structure is unstable and that the ordering is a slow process at ambient conditions. Upon compression, β-NaNdF(4), β-NaGdF(4) and the superstructure NaPrF(4) are stable to at least 8 GPa with no evidence for any pressure-induced disorder-order phenomena.
LB  - PUB:(DE-HGF)16
C6  - pmid:22797523
UR  - <Go to ISI:>//WOS:000307306400020
DO  - DOI:10.1039/c2dt30650f
UR  - https://juser.fz-juelich.de/record/111852
ER  -