1070-3284/02/2809- $27.00 © 2002
Russian Journal of Coordination Chemistry, Vol. 28, No. 9, 2002, pp. 630–634. Translated from Koordinatsionnaya Khimiya, Vol. 28, No. 9, 2002, pp. 671–675.
Original Russian Text Copyright © 2002 by Kavun, Gerasimenko, Sergienko, Davidovich, Antokhina.
In this investigation, we continue structural studies
of crystalline ﬂuorides of Group IV elements with uni-
valent alkali, ammonium, and thallium(I) cations and
studies of ion dynamics in complex ﬂuorides [1–4].
This paper presents structural data for ammonium
) and data on the ion
dynamics in this compound.
X-ray diffraction analysis
was performed for a
naturally edged single crystal using a SMART 1000
CCD diffractometer (Bruker Co.) Data were collected
in sets containing 606, 435, and 230 frames at
scan mode. The
between the frames was
. Reﬂections from each
frame were recorded within 10 s. A correction for X-ray
absorption in the sample was applied. The structure was
solved using the heavy atom method and reﬁned by the
least-squares method in anisotropic approximation for
all non-hydrogen atoms. The hydrogen atoms of the
ammonium groups were not located.
Data collection and processing, as well as reﬁne-
ment of the unit cell parameters, were carried out with
the SMART and SAINT Plus programs . All calcu-
lations for structure determination and reﬁnement were
performed using the SHELXTL/PC programs .
Selected crystallographic data and a summary of
data collection are given in Table 1. Atomic coordinates
and isotropic equivalent thermal parameters are pre-
sented in Table 2.
(first derivatives of
absorption lines) of polycrystals
were recorded on
a Bruker SWL 3-100 stationary spectrometer
(84.66 MHz) in the temperature range 200–420 K. The
NMR data were processed as described in . The acti-
vation energy of local motion was estimated by the
Waugh–Fedin formula from the temperature depen-
dences of the second moment (
) of the NMR spectra
Complex Ions in Ammonium Hexafluorohafnate: Crystal
Structure and Internal Dynamics
V. Ya. Kavun, A. V. Gerasimenko, V. I. Sergienko,
R. L. Davidovich, and T. F. Antokhina
Institute of Chemistry, Far East Division, Russian Academy of Sciences,
pr. Stoletiya Vladivostoka 159, Vladivostok, 690022 Russia
Received March 21, 2001
—The crystal structure of
was determined using a SMART 1000 CCD diffractometer
radiation, graphite monochromator). The unit cell parameters are
= 13.3902(7) Å,
= 7.6850(4) Å,
= 11.6731(6) Å, space group
= 8; least-square reﬁnement in the anisotropic approximation gave
= 0.0682. The compound is isostructural to
. The dynamics of the complex
ions was examined in the temperature range 200–425 K; the energy of their activation was estimated. It
was found that compounds of the
type (A = Zr or Hf) can be classiﬁed as superionic conductors at
380 to 425 K.
Fragment of an inﬁnite chain of Hf polyhedra in