Reactivity and Structural Defects in Glaserite-Type Iron-Vanadates

Article abstract of DOI:10.1002/zaac.201800360

We investigated (a) the redox reaction of FeO and Ag₂O in the presence of BaCO₃ and V₂O₅ under inert atmosphere and (b) the oxidation of FeO in air in the presence of BaCO₃, Na₂CO₃, and V₂O₅. The reaction products are members of the glaserite-type of compounds: Ba(Ag□)Fe[VO₄]₂ [a = 5.47397(4) ?, c = 7.1780(1) ?, P3]; BaNa_1.63Fe_0.79[VO₄]₂ [a = 9.672(1) ?, b = 5.5860(6) ?, c = 14.1505(4) ?, β = 90.042(9)°, C2/c]; and Ba(Ba,Na)Na[VO₄]₂ [a = 5.8478(2) ?, c = 7.3835(3) ?, P3m1]. The latter presents an example for a statistical distribution of differently charged ions with differences in ionic radii (Ba²⁺ and Na⁺) on the B site of the general formula AB₂M[VO₄]₂. The iron compounds exhibit differences in the defect concentration and localization of voids. For Ba(Ag□)Fe[VO₄]₂ the Fe³⁺-triangular lattice remains intact and the Ag substructure is depleted by 50 % through the redox reaction (a). In contrast, for BaNa_1.63Fe_0.79[VO₄]₂ defects occur on both sites (B = Na⁺ and M = Fe³⁺) with a total of 0.58 defects per formula unit. Extended ⁵⁷Fe-M?ssbauer studies on a series of Fe-glaserite compounds relate structural findings from Rietveld refinements of X-ray diffraction data with defect concentrations, substitution variants, and charge distributions.

Full text of DOI:10.1002/zaac.201800360

Journal of Inorganic and General Chemistry
DOI: 10.1002/zaac.201800360
ARTICLE
Zeitschrift für anorganische und allgemeine Chemie
Reactivity and Structural Defects in Glaserite-Type Iron-Vanadates
Anna Reuß,[a] Vadim Ksenofontov,[a] Joshua Tapp,[a] and Angela Möller*[a]
Dedicated to Professor Dr. Wolfgang Bensch on the Occasion of his 65th Birthday
Abstract. We investigated (a) the redox reaction of FeO and Ag
the presence of BaCO and V under inert atmosphere and (b) the
oxidation of FeO in air in the presence of BaCO , Na CO , and V
2
O in
AB
2
M[VO
4
]
2
. The iron compounds exhibit differences in the defect
the
3
2
O
5
concentration and localization of voids. For Ba(Agᮀ)Fe[VO ]
4 2
3
+
3
2
3
2
O
5
.
Fe -triangular lattice remains intact and the Ag substructure is de-
The reaction products are members of the glaserite-type of compounds:
¯
pleted by 50% through the redox reaction (a). In contrast, for
+
Ba(Agᮀ)Fe[VO
4
]
2
[a
=
5.47397(4) Å,
c
=
=
7.1780(1) Å, P3]; BaNa1.63Fe0.79[VO
4
]
2
defects occur on both sites (B = Na and M =
3
+
BaNa1.63Fe0.79[VO
4
]
2
[a
=
9.672(1) Å,
b
5.5860(6) Å,
c
=
Fe ) with a total of 0.58 defects per formula unit. Extended
5
7
1
4.1505(4) Å, β = 90.042(9)°, C2/c]; and Ba(Ba,Na)Na[VO
4
]
2
[a =
Fe-Mössbauer studies on a series of Fe-glaserite compounds relate
¯
5.8478(2) Å, c = 7.3835(3) Å, P3m1]. The latter presents an example structural findings from Rietveld refinements of X-ray diffraction data
for a statistical distribution of differently charged ions with differences with defect concentrations, substitution variants, and charge distribu-
in ionic radii (Ba2 and Na ) on the B site of the general formula tions.
+
+
Introduction
The family of AB M[XO ] compounds belong to the gla-
2
4 2
serite-type of structures. These crystallize in three derivatives
¯
¯
+
[1]
with reported space groups P3m1, P3, and C2/c. The cations
+
+
2+
2+
+
+
3+
3+
A (Rb , K , Ba , Sr , Ag ), B (Na , Ag ), and M (In , Cr ,
Fe , Mn , Fe , Co , Ni , Mg ) differ in their ionic radii
3
+
2+
2+
2+
2+
2+
and coordination. In general, r Ն r Ն r is observed with
A
B
M
coordination numbers of 6+6 (A), max. 10 (B), and 6 (M). The
complex tetrahedral entities [XO ] (X = S, Mo, V, or P) in the
4
highest oxidation states present a rigid group, which connects
to all cations. Thus, the relative cation sizes (r /r ) determine
A
B
the relative orientation of this complex anion, (i) aligned,
ii) rotated, or (iii) tilted with respect to the crystallographic
(
c axis (see Figure 1, for selected structural reports see refer-
ences[ ).
2–9]
In recent years the 3d-transition metal compounds have
triggered interest as these present examples for magnetic tri-
[10]
[11–13]
angular lattices
with ferromagnetic,
or spin-liquid like[17] ground states. From substitu-
tion variants on the M site by diamagnetic ions or defect
antiferromag-
netic,[
14–16]
4
Figure 1. Left: An overview on the relative orientation of [VO ] and
vacancies, ratio M:(MЈ or ᮀ) = 2:1, honeycomb lattices may be [MO ] polyhedra for the three structure types (i)–(iii). Middle: Respec-
6
obtained.[
18,19]
However, the ordered, undistorted and planar tive variations from C.N. 10 for B-site cations with the first coordina-
tion sphere depicted as polyhedra. Right: Distorted cube-octahedral
honeycomb or kagome lattice for fundamental studies of low-
dimensional magnetic materials remains a chemical chal-
lenge.[
coordination of the A-site cation present for all structure types.
20,21]
Among the glaserite-type compounds, of AB M[XO ] , one
2
4 2
case M = Fe2+ and X = V stands out because the binary
+5
*
Prof. Dr. A. Möller
E-Mail: angela.moeller@uni-mainz.de
oxides, FeO and V O , have no common coexistence in the
2
5
[22]
[
a] Institute of Inorganic Chemistry and Analytical Chemistry
Johannes Gutenberg Universität Mainz
Duesbergweg 10–14
thermodynamic limit.
Thus, redox reactions should occur.
However, intermediates such as ternary oxides resulting from
acid-base principles may prevent the expected oxidation of
55128 Mainz, Germany
Supporting information for this article is available on the WWW
under http://dx.doi.org/10.1002/zaac.201800360 or from the au-
thor.
2
+
3+
+5
Fe
to Fe
and simultaneous reduction of V , see
[9,12]
BaNa Fe[VO ]
as an unprecedented case. Therefore, we
2
4 2
Z. Anorg. Allg. Chem. 0000, ᭿,0–0
1
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Journal of Inorganic and General Chemistry
ARTICLE
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have investigated the reactivity in the presence of B = Ag and Fe2+ to Fe3+ in air. The final step (III) is identical with the
+
+
Na in the BaB Fe[VO ] series. Beyond the thermal analysis reaction in an argon atmosphere namely the decomposition of
2
4 2
and ex-situ reactivity studies we employ X-ray diffraction and Na CO . We observe additional endothermal effects at ele-
2
3
5
7
Fe-Mössbauer spectroscopy to reveal defects required for vated temperatures above 800 K without any mass change
3
+
charge compensation in the case of Fe .
which we assign to the formation of polynary phases contain-
ing sodium.
Results and Discussion
Reactivity
Thermal Analysis
We used powder X-ray diffraction techniques to characterize
the respective reaction products and refined the data by Riet-
veld methods, from which we gain insights into the phase com-
positions for the crystalline components. First, we discuss the
reaction of BaCO , Ag O, FeC O ·2H O, and V O in an inert
The decomposition of FeC O ·2H O as a reactive source for
2
4
2
FeO is well known.[
23,24]
Herein we use this precursor step to
introduce reactive FeO in the presence of BaCO , Na CO , or
3
2
3
Ag O, and V O for our investigation by difference-thermal
2
2 5
3
2
2
4
2
2 5
analysis coupled with thermogravimetry (DTA/TG) in air and
an argon atmosphere (see Figure 2). From the DTA curves we
find the first step of the thermal decomposition below 450 K,
atmosphere. Indeed the products are Ba(Agᮀ)Fe[VO ] and
4
2
silver metal at 773 K, which confirms the redox reaction sug-
gested from thermal analysis above. Hence, it can be con-
which essentially presents
a
dehydration process of
2
+
+
cluded that the redox reaction between Fe and Ag is favored
FeC O ·2H O (I). In an argon atmosphere the second step oc-
2
4
2
+5
over the reduction of V . This is in agreement with the larger
curs around 650 K and is mainly ascribed by the endothermal
decomposition of FeC O and BaCO yielding CO and CO
2
difference in partial O pressure between the coexisting re-
2
2
4
3
gimes of FeO and Ag O in the thermodynamic limit (see also
2
(
II). Noticeable is the exothermal effect occurring simulta-
reference[ ). Pure brick-red Ba(Agᮀ)Fe[VO ] [type (ii)] can
22]
+
+
4 2
neously for B = Ag whereas it is absent for B = Na . We
be also be obtained directly by reacting BaCO , ½Ag O,
3
2
assign the exothermal effect to a redox reaction that involves
FeO(OH), and V O (see Figure 3a).
2 5
+
2+
3+
the reduction of Ag to Ag and an oxidation of Fe to Fe .
Figure 2. Thermal analysis of the reactants: BaCO
FeC ·2H O, and V in molar ratios of 1:1:1:1 in an argon atmo-
sphere (red line) and in air (blue line). The grey line presents the
reaction of BaCO , Ag O, FeC ·2H O, and V (molar ratio
:1:1:1) in an argon atmosphere. (I)–(III) denote the three-step process
referring to the mass-loss described in the text.
3 2 3
, Na CO ,
2
O
4
2
2 5
O
3
2
2
O
4
2
2 5
O
1
The decomposition of the carbonates is also dependent on
the partial pressure of CO stemming from the oxalate at a Figure 3. X-ray diffraction data and Rietveld refinements for
2
Ba(Agᮀ)Fe[VO (a). The main phase BaNa1.63Fe0.79[VO
4
]
2
4 2
] (b), and
given reaction temperature. However, since the additional final
step above 750 K occurs only for B = Na (III) our conjecture
+
Ba(BaNa)Na[VO ] (c). Circles: experimental data, red line: calculated
4 2
diffraction pattern, and blue line: difference experimental and calcu-
lated intensities. Markers indicate the respective Bragg positions for
is that BaCO decomposes first. The mass loss expected for
3
the evolution of one CO from Na CO of ca. 7% is in good the contributing phases.
2
2
3
agreement with the observation. Hence, it is conceivable that
the formation of polynary products is enhanced for A = Ba .
2+
In order to suppress the redox process with the B-site cation
+
If the reaction with B = Na is conducted in air, we note we chose to substitute Ag O by Na CO . In this case we obtain
2
2
3
2+
that the onset temperature of the FeC O decomposition black BaNa Fe[VO ] containing Fe and no further oxidation
2
4
2
4 2
around 500 K is lowered by 150 K (II). Additionally, an exo- of iron is observed in an argon atmosphere up to 973 K (see
[9]
thermal effect is detected and indicates the direct oxidation of also reference ).
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To address the question if the nominal charge balanced
With the c/a ratio the distortion of the coordination around
+
BaNa (Fe2/3ᮀ1/3)[VO ] can be obtained we precede with re- the B cation changes from 4+3 (B = Ag ) to almost spherical
2
4 2
+
actions carried out in air. Using FeC O ·2H O as a precursor 6 for B = Na . Again providing insights into the structure re-
2
4
2
3
+
+
+
for FeO immediate oxidation to Fe occurs upon decomposi- sponse to chemically hard (B = Na ) and softer (B = Ag ) ions,
+
tion of the oxalate. Surprisingly, we obtain a defect variant: respectively. The spherical coordination sphere for B = Na is
BaNa1.63Fe0.79[VO ] , type (iii), with vacancies on the Na- and further facilitated by the space group symmetry reduction,
4 2
Fe substructures (Figure 3b). This main product can be con- which allows tilting of the vanadate off the c axis.
firmed by reactions with FeO(OH) in air and inert atmosphere
For comparison, the c/a ratio equals 1.26 for
for reaction temperatures of up to 973 K. Furthermore, we note Ba(BaNa)Na[VO ] which reveals the structural strain of com-
4
2
¯
that the crystalline phase composition determined from X-ray pression in the high-symmetry space group P3m1, originating
diffraction data analysis consists of BaNa1.63Fe0.79[VO ] (ca. from the preferred spherical coordination around the “hard” B-
4 2
7
6%) and Ba V O (ca. 20%) with approximately 4% Fe O . site cation. Note that the statistical occupancy on this site in-
2 2 7 2 3
In conclusion, the proposed defect structure exclusively on volves the larger Ba2+ and Na in a 1:1 ratio with ionic radii
+
the Fe site (BaNa (Fe2/3ᮀ1/3)[VO ] ) is not observed and sug- of ca. 1.5 and 1.0 Å, respectively. Thus, the larger C.N. 10 for
2
4 2
gests a less favorable/stable unsupported honeycomb lattice of the B site is conceivable.
highly charged transition metal cations. We rather find the Na
Next we investigate the effects of distortion, defects and
sites less than fully occupied. One may speculate if this out- substitution on the M site by the local probe of 57Fe-Mössbauer
come originates from the differences in decomposition tem- spectroscopy. We extend our studies to size and charge differ-
+
+
+
3+
peratures between BaCO and Na CO (see Figure 2 above). ences on the A site (Rb , K , and Ag ) for triangular Fe
3
2
3
Principles of the HSAB concept additionally mark subtle dif- substructures and include a honeycomb variant with M =
3
+
3+
+
ferences in the formation and the dissimilar defect distributions 2/3Fe , 1/3In . Except for the smaller A = Ag (C2/c) all
¯
of Ba(Agᮀ)Fe[VO ] and BaNa1.63Fe0.79[VO ] . The “softer” other reference compounds crystallize in the space group P3.
4
2
4 2
Ag ion easily compensates the defects while retaining the Fe-
triangular lattice. In contrast, the “harder” Na ion competes
with the transition metal to give rise to a reproducible statistics
on B- and M-site occupations.
Mössbauer Spectroscopy
57Fe-Mössbauer spectroscopic hyperfine parameters are ob-
In a second sequence of reactions we limit the reactant
tained from Lorentzian site analysis of the measured spectra.
All spectra (Figure 4) can be fitted with a typical linewidth
Na CO (e.g. Ba:Na:Fe:V equal to 1:1:1:2). Interestingly, we
2
3
do not observe the formation of BaNa1.63Fe0.79[VO ] at all
–1
4 2
(w ≈ 0.16 mm·s ) and indicate single crystallographic sites
and obtain instead only Fe O (ca. 23%) and Ba V O (ca.
3+
2
3
2
2
7
for Fe . The hyperfine parameters reveal information on the
77%). For a control experiment we reacted BaCO3 and
oxidation state of iron (chemical shift, CS) and the charge dis-
tribution around the iron nucleus (quadrupole splitting,
Na CO with V O (ratio 2:1:1) in the absence of iron com-
2
3
2
5
pounds and we obtained Ba(BaNa)Na[VO4]2 (Figure 3c), a
glaserite-type compound (i) isotypic with the high-temperature
modification of BaNaPO4[ (for details see Supporting Infor-
2]
+
mation). Here the B-site is statistically occupied by Na and
2+
Ba and an ordered occupancy of A- and M-sites is found.
+
Note that Na is localized in environments with coordination
numbers of 10 (B) and 6 (M) here (see also Figure 1).
Structural Aspects
Details on the Rietveld refinement and crystallographic data
are listed in the Supporting Information. Typically, the sodium
compounds crystallize in the space group C2/c with the angle
¯
β ≈ 90°, whereas the silver compounds are less distorted (P3).
We use the respective ratios of the c/a lattice constants of the
(pseudo-)trigonal unit cell with Z = 1 to reveal subtle differ-
ences. The degree of compression along the c axis and sub-
sequently elongation along the a axis can be expressed by the
+
+
c/a ratio: 1.31 (B = Ag ) and 1.27 (B = Na ) for the title
compounds. We find for the former case almost ideal FeO6
octahedral entities, whereas slightly compressed and distorted
polyhedra are observed for the latter with average distances of
d(Fe–O) ≈ 1.99 Å.
Despite the identical size of the B cations (Ag and Na )
dissimilar distances are found for the coordination spheres (see
also Figure 1).
Figure 4. 57Fe-Mössbauer spectra collected at room temperature
and Lorentzian fits to doublets, see also Table 1. For the
+
+
BaNa1.63Fe0.79[VO
4
]
2
2 3
sample the impurity phase Fe O (magnetic sex-
tet) is clearly observed.
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Table 1. 57Fe-Mössbauer spectroscopic hyperfine parameters at room temperature from Lorentzian fits, ratio of ionic radii for A- and M-site
¯
ions, and ratio of lattice constants, a and c, for P3 and the reduced cell (Z = 1) in a pseudo-hexagonal setting for the C2/c structures.
Compound
CS /mm·s–1
QS /mm·s–1
A/M
c/a
RbAg
RbAg
2
2
(Fe2/3In1/3)[VO
Fe[VO
4
]
2
0.410(2)
0.403(3)
0.401(2)
0.386(1)
0.396(4)
0.407(3)
0.11(1)
0.09(1)
0.12(1)
0.36(1)
0.32(1)
0.41(1)
2.47
2.67
2.54
2.50
2.50
1.55
1.35
1.35
1.32
1.31
1.27
1.34
4 2
]
KAg
2 4 2
Fe[VO ]
Ba(Agᮀ)Fe[VO ]
BaNa1.63Fe0.79[VO ]
4 2
AgAg
4 2
a)
a)
2 4 2
Fe[VO ]
a) C2/c structures.
3+
QS).[25,26] Typical CS values for Fe3+ range from 0.4 to fect concentrations and site preferences for the Fe com-
–
1
+
+
0
.5 mm·s . At room temperature we observe slightly smaller pounds with B = Na or Ag . Structure refinements indicate
CS shifts for BaNa1.63Fe0.79[VO ] and Ba(Agᮀ)Fe[VO4]2 that the B-site cations relate to differences in the c/a lattice
4 2
compared to our reference compounds AAg Fe[VO ] (A = constant ratio, e.g. elongated and compressed [FeO ] com-
2
4 2
6
+
+
+
57
Ag , K , and Rb ) or RbAg (Fe2/3In1/3)[VO ] (see Table 1).
plexes, respectively. Fe-Mössbauer spectroscopic data reveal
2
4 2
3+
The main difference in the recorded spectra relates to the the impact of defects on Fe through the complex bridging
quadrupole splitting of nuclear energy levels which is associ- unit [VO ] . Statistically, the charge distribution of the tetra-
3–
4
ated with the electric field gradient present for non-cubic space hedral unit is susceptible not only to voids in the coordination
group symmetries (here: c/a ratio) and surroundings of the but also to the respective concentration of unoccupied sites
Mössbauer active nuclei with anisotropic charge distributions (defects). This will trigger unequal Fe–O distances and impact
like defect sites or diamagnetic substituents. All compounds of the general local distortion, which effects also the O–Fe–O
3
+
5
the series contain Fe (3d , non-degenerate ground state) in a angles. Hence, the quadrupole splitting increases with the
¯
slightly distorted [FeO ] polyhedron of D (P3) or C sym- number of defects. On the other hand, samples without defect
6
3d
i
metry (C2/c). The QS almost vanishes for the former cases and sites originating from subtle charge neutrality do not exhibit
increases with space group symmetry reduction. This trend is such a dependence of the QS at room temperature, compare to
nicely followed for compounds where all B and M sites are the honeycomb compound RbAg (Fe2/3In1/3)[VO ] .
2
4 2
fully occupied, even with partial non-magnetic substituents
3
+
(
In ).
¯
Although for Ba(Agᮀ)Fe[VO ] (P3) the A/M radii ratio
4
2
Experimental Section
and c/a parameters suggest a vanishing QS (less than the line
width of 0.16 mm·s ), we observe a significant quadrupole
–
1
4 2 0.79 4 2
Powder samples of Ba(Agᮀ)Fe[VO ] , BaNa1.69Fe [VO ] , and
Ba(BaNa)Na[VO4]2 of the general AB M[VO ] type were prepared
2 4 2
–
1
splitting of 0.36(1) mm·s that originates from local aniso-
tropic charge distributions arising from defect sites on the Ag+
by solid state techniques in air and an argon atomsphere, respectively,
from BaCO (99.8%; Alfa Aesar), Ag O (99%, Alfa Aesar) or
Na CO (99.5%, Acros), FeC ·2H O (99%; Alfa Aesar) or
FeO(OH) (catalyst grade, Sigma Aldrich), and V (99.2%; Alfa
3
2
substructure. Interestingly, the lower defect concentration in
BaNa1.63Fe0.79[VO ] (total only 0.58 vacancies) gives rise to a
smaller QS (Figure 4) despite the lower space group symmetry
2
3
2
O
4
2
4 2
2 5
O
Aesar). Molar ratios of A:B:M:V of 1:2:1:2, 1:1:1:2, 1:2:0.67:2, and
1:1:0:1, respectively, were investigated. The reactants were mixed,
[5]
(
compare to Ag Fe[VO ] and Na Fe[PO ] ). Thus, it is
3 4 2 3 4 2
tempting to relate this finding to the presence of a more iso- ground manual or ball-milled (corundum crucibles and balls, Retsch
tropic charge distribution arising from the statistics on B and PM 100). The powder mixtures were placed into open silica tubes and
M sites, as well as to the more spherical coordination sphere then into a secondary silica tube. After multiple cycles of evacuating
with interim purging, the samples were heated in a dry argon atmo-
around the Na ion.
sphere at a rate of 50 K per minute to 773 K for 3 h. The sample was
allowed to cool down naturally to room temperature, reground into a
fine powder, and pressed into pellets. These pellets were annealed un-
der similar conditions as described above for 36 h at 873 K or 973 K.
Conclusions
We have studied the reactivity of binary oxides without co- A similar protocol was used for the reactions in air. We used samples
existing thermodynamic stability ranges at given oxygen par- of ground reaction mixtures for thermal analysis measurements on a
tial pressures, here FeO in the presence of V O and Ag O. NETZSCH (STA449-F3-Jupiter) instrument in an argon atmosphere
2
5
2
–
1
and in air with a constant flow rate of 20 mL·min . X-ray diffraction
experiments were carried out with a STADI P (Stoe) using monochro-
matic Mo-Kα1 or Ag-Kα1 radiation in transmission. Rietveld refine-
Redox reactions involving FeO occur only with Ag O but not
with V O during the simultaneous thermal decomposition of
barium- and sodium carbonates. The carbonates and Ag O re-
act readily with the acidic oxide V O to polynary vanadates.
With this work we have expand the family of the glaserite-
type of structures by three new members: Ba(Agᮀ)Fe[VO ] ,
2
2
5
2
ments of powder X-ray diffraction data were carried out using the
Fe-Mössbauer spectroscopic data were collected
with a custom build setup at 293 K. The velocity data was standardized
2
5
[27] 57
program Topas.
4
2
using α-iron foil and the spectra were fitted using the program Re-
BaNa1.63Fe0.79[VO ] , and
Ba(BaNa)Na[VO4]2.
These
[28]
4 2
coil.
The reference compounds were synthesized according to the
[
19]
AB M[VO ] compounds represent three principal structure procedures described in the literature
using K CO (anhydrous,
2
4 2
2
3
2 3
types of glaserite phases. Interestingly, we find dissimilar de- 99%, Alfa Aesar), Rb CO (99.9% metals basis, Alfa Aesar), and
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Journal of Inorganic and General Chemistry
ARTICLE
Zeitschrift für anorganische und allgemeine Chemie
2 3
In O
(99.9% metals basis, Alfa Aesar). The purity of the obtained [11] A. Möller, N. E. Amuneke, P. Daniel, B. Lorenz, C. R. de la Cruz,
M. Gooch, P. C. W. Chu, Phys. Rev. B 2012, 85, 214422.
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products was confirmed by X-ray diffraction data refinements.
[
Supporting Information (see footnote on the first page of this article):
Crystallographic data, atomic positions and selected interatomic
14849.
[
[
13] A. A. Tsirlin, A. Möller, B. Lorenz, Y. Skourski, H. Rosner, Phys.
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distances for BaAgᮀFe[VO
4
]
2
,
BaNa1.63Fe0.79[VO
4
]
2
,
and
4 2
BaNa1.63Fe0.79[VO ] .
Acknowledgements
267205.
[
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Received: August 16, 2018
Published online: ᭿
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Z. Anorg. Allg. Chem. 0000, 0–0
www.zaac.wiley-vch.de
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© 0000 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Journal of Inorganic and General Chemistry
ARTICLE
Zeitschrift für anorganische und allgemeine Chemie
A. Reuß, V. Ksenofontov, J. Tapp, A. Möller* .................. 1–6
Reactivity and Structural Defects in Glaserite-Type Iron-Vana-
dates
Z. Anorg. Allg. Chem. 0000, 0–0
www.zaac.wiley-vch.de
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© 0000 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim