Synthesis and characterisation of Na5[CoO2]CO3

Article abstract of DOI:10.1515/znb-2002-1219

Na₅[CoO₂]CO₃ was prepared via the azide/nitrate route. Stoichiometric mixtures of the precursors (Co₃O₄, NaN₃, NaNO₃ and Na₂CO₃) were heated in a special regime up to 500°C and annealed at this temperature for 50 h in silver crucibles. Single crystals have been grown by subsequent annealing of the powder at 500°C for 2000 h in silver crucibles, which were sealed in glass ampoules under dry Ar. According to the X-ray analysis of the crystal structure (P4/mmm, Z = 1, a = 4.6467(4), c = 8.2577(6) A?). Na₅[CoO₂]CO₃ is isostructural with Na₅[NiO₂]CO₃ and contains Co¹⁺, which is coordinated by two oxygen atoms forming a dumb-bell. Na₅CoCO₅ decomposes at 600°C to Na₃CoO₂ and Na₂CO₃.

Full text of DOI:10.1515/znb-2002-1219

1461
Synthesis and Characterisation of
Na [CoO ]CO
At this temperature Na
CoCO begins to decom-
5 5
pose into Na CoO and Na CO .
3
2
2
3
5
2
3
The crystal structure of the novel sodium co-
baltate carbonate (Fig. 1) was determined from
single crystal data. Details of the refinement and
crystallographic data are given in Tables 1 and 2.
Mikhail Sofin, Eva M. Peters, and
Martin Jansen
Max-Planck-Institut für Festkörperforschung,
Heisenbergstrasse 1, D-70569 Stuttgart, Germany The characteristic feature of the structure is the
3
Ð
linear CoO -anion. The Co-O bond length is
2
Reprints requests to Prof. Dr. M. Jansen.
Fax: +49-(0)711-6891502.
˚
1
.755 A and the O-Co-O angle is 180∞. The struc-
tural features related to the cobaltate(I) anion are
in a good agreement for all known alkali metals
compounds [3Ð6]. According to the structure
obtained from single crystal data (Table 2), the
carbonate unit is orientationally disordered. The
situation has been addressed appropriately by ap-
plying a split atom model. To confirm the presence
E-mail: m.jansen@fkf.mpg.de
Dedicated to Professor Albrecht Mewis on the
occasion of his 60th birthday
Z. Naturforsch. 57b, 1461Ð1463 (2002);
received September 9, 2002
5 2 3
Na [CoO ]CO was prepared via the azide/nitrate
route. Stoichiometric mixtures of the precursors of the carbonate ion, an IR spectrum of
Co , NaN , NaNO and Na CO ) were heated Na [CoO ]CO has been recorded (Fig. 2, Table 3).
(
O
3 4
3
3
2
3
5
2
5
in a special regime up to 500 ∞C and annealed at
this temperature for 50 h in silver crucibles. Single
crystals have been grown by subsequent anneal-
ing of the powder at 500 ∞C for 2000 h in silver
crucibles, which were sealed in glass ampoules un-
der dry Ar. According to the X-ray analysis of the
crystal structure (P4/mmm, Z = 1, a = 4.6467(4),
˚
c = 8.2577(6) A). Na
with Na [NiO ]CO and contains Co , which is
coordinated by two oxygen atoms forming a
dumb-bell. Na CoCO decomposes at 600 ∞C to
Na CoO and Na CO
5 2 3
[CoO ]CO is isostructural
1
+
5
2
3
5
5
3
.
3
2
2
Key words: Cobalt(I), Crystal Structure, Azide/
Nitrate Route
Introduction
At exploring the synthetic potential of the azide/
nitrate route [1] for the preparation of alkalioxo-
metalates we have tried to prepare representatives
containing two different types of complex anions.
As the first case we have selected Na [CoO ]CO ,
5
2
3
since recently the corresponding nickel compound
2] had been obtained through the conventional
[
solid state reaction involving sodium oxide.
Results and Discussion
Na [CoO ]CO can be readily prepared by the
5
2
3
azide/nitrate route [1] as a micro-crystalline pow-
der. The ruby-red products are very sensitive to
air and moisture. The DTA/TG analysis has shown
that no chemical reactions or phase transitions oc-
Fig. 1 Crystal structure of Na
5 2 3
[CoO ]CO . The octahe-
dron in the central section of the picture corresponds to
cur during heating of the substance up to ~ 600 ∞C. the orientationally disordered carbonate unit.
0
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D
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462
Table 1. X-ray and crystallographic
data for Na [CoO ]CO (293 K).
Crystal data
5
2
3
Crystal system
tetragonal
Space group, Z
P4/mmm (No. 123), 1
a = 4.6467(4)
c = 8.2577(6)
2.474
Lattice constants (from X-
˚
ray powder data) [A]
3
Calculated density [g/cm ]
Crystal shape, color
Crystal size, mm
irregular, red
0.15 ¥ 0.1 ¥ 0.1
Structure refinement
Method of refinement
Parameters refined
Full-matrix least-squares on F2
25
2
R1 (F
wR2
0
> 4sigF
0
/all)
0.0436/0.0548
0.1107
2
2
2
weight
0
w = 1/(σ (F ) + (0.0476·P) + 0.44·P),
2 2
where P = (max(F
0 c
,0) + 2·F )/3
Ð
˚
3
∆ρmin, ρmax [e /A ]
Ð 1.20/1.14
Data collection
Diffractometer
Monochromator
Bruker AXS, APEX SMART-CCD
Graphite
˚
Mo-K
α
Radiation, [λ]
0.71073 A
2
θ Range for data collection
2θ < 75.0∞
Range of h,k,l
Ð6 < h < 6, Ð7 < k < 6, Ð11 < l < 10
Total no. reflection
Unique reflections
Observed reflections
Absorption coefficient, µ [mmÐ1]
F(000)
1635
225
1635
2.67
122
˚
2
4
Table 2. Atomic coordinates and anisotropic displacement parameters (in A ·10 ) for Na
5 2 3
[CoO ]CO .
Atom
Position
x
y
z
U
11
U
22
U
33
Co1
Na1
Na2
O1
1a
1b
4i
0
0
0
0
0
174(6)
174(6)
149(7)
0
0.5
362(16)
678(20)
183(15)
670(79)
503(84)
614(78)
362(16)
142(11)
183(15)
670(79)
435(76)
614(78)
182(19)
384(13)
179(21)
1
⁄
2
0.2403(3)
0.2125(6)
0.345(2)
0.5
2 g
0
0
a
1
1
O2
2h
⁄
⁄
⁄
2
⁄
2
723(125)
530(79)
452(92)
a
1
1
O3
C1
4o
2
2
0.195(3)
b
1
1d
⁄
2
0.5
U
12 = U13 = U23 = 0 for all atoms;
a
site occupation factor: 0.5;
b
disordered, average site position.
Experimental Section
vacuum (10Ð3 mBar) at 150 ∞C for 12 h and placed
under argon in a tightly closed steel vessel pro-
Starting materials for the preparation of Na5- vided with a silver inlay [1]. In a flow of dry argon
[
CoO ]CO were sodium azide (Aldrich, 99.5%), the following temperature profile was applied:
2
3
sodium nitrate (Aldrich, 99%), sodium carbonate 255260 ∞C (100 K/h); 2605380 ∞C (5 K/h),
(
Merck, 99.9%) and cobalt oxide Co O . Cobalt 3805500 ∞C (10 K/h) and subsequent annealing
3
4
oxide Co O4 was prepared by heating for 50 h at 500 ∞C. The red powder obtained is ex-
3
Co(C O )·2H O in a flow of oxygen at 375 ∞C for tremely sensitive to air. It was sealed in glass am-
2
4
2
4
0 h. The starting materials (NaN , NaNO , poules under argon atmosphere. All following ma-
3 3
Na CO and Co O ) were mixed in the ratio re- nipulations with this substance were also
2
3
3
4
quired according to the equation
performed in inert atmospheres of purified argon
5 NaN + 2 NaNO + 9 Na CO + 3 Co O = or nitrogen. The X-ray investigation on powder
2
3 3 2 3 3 4
9
Na [CoO ]CO + 38.5 N , milled in a planet ball
5 2 3 2
5
mill, pressed in pellets under 10 N, dried under
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1463
Table 4. Powder diffraction data of Na
5
[CoO
2
]CO
3
(d >
0
0
0
0
0
0
0
.9
.8
.7
.6
.5
.4
˚
1.4 A).
˚
h
k
l
d [A]
I/I
0
[%]
0
1
1
1
1
1
0
1
1
2
2
1
2
0
2
2
1
2
1
0
2
2
1
3
2
2
3
3
2
3
3
0
0
0
1
0
1
0
1
0
0
0
1
1
0
0
1
0
1
1
0
2
2
0
0
0
2
0
1
1
0
1
1
0
1
0
2
1
3
2
3
0
1
3
0
4
2
1
4
2
4
5
0
1
5
0
4
2
1
0
4
2
1
8.2721
4.6495
4.0515
3.2866
3.0874
3.0538
2.7535
2.5716
2.3673
2.3238
2.2371
2.1104
2.0785
2.0648
2.0252
2.0156
1.8869
1.8564
1.7480
1.6517
1.6430
1.6116
1.5563
1.5496
1.5433
1.5266
1.5224
1.4691
1.4647
1.4501
1.4465
3.7
54.4
100.0
9.7
8.0
3.1
1.3
77.8
0.9
.3
4
81.4
1.9
000
3500
3000
2500
2000
1500
1000
500
2.7
-1
22.1
21.4
2.1
Wawenumber [cm ]
5 2 3
Fig. 2 IR spectrum of Na [CoO ]CO (in KBr).
7.0
12.4
7.1
Table 3. Vibrational data (in cmÐ1) and assignment for
1.2
0.8
Na
5
[CoO
2
3
]CO at 293 K.
13.3
1.5
modes
Wawenumber
3.4
0.4
2
ν
2
ν
ν
ν
ν
ν
ν
ν
3
2875
2499
2121
1779/1750
1427
1043
881
1
+ ν
2
18.9
1.0
ν
1
1
3
1
2
+ ν
4
2.6
1.2
11.5
1.4
3
Ð)
as(CoO
4
2
736
0.6
685
ν(Na-O)
523
The crystal structure of the sodium carbonate oxo-
cobaltate was determined from X-ray single crys-
was performed on a STOE Stadi P diffractometer tal data. The lattice constants were refined from
˚
with Co-Kα1 radiation (λ = 1.78896 A) at room powder data. Details of structural refinement and
temperature using a position sensitive detector crystallographic data are given in Table 1. Infrared
and a curved germanium monochromator. The experiments were carried out on powder samples
powder diffraction data are given in Table 4. Sin- in KBr discs (handled under Ar) on a Bruker IFS
gle crystals have been grown by subsequent an- 113v spectrometer. Thermal analyses were carried
nealing of the as prepared powder at 500 ∞C for out using a DTA/TG device (STA 409, Netzsch)
2
000 h in silver crucibles, which were sealed in coupled with a quadrupole mass spectrometer
glass ampoules under dry Ar. Single crystals for (QMG 421, Balzers, Wetzlar). The probe (m =
X-ray diffraction have been selected in Ar atmo- 26.5 mg) was heated at a rate of 10 K/min in a co-
sphere using a microscope attached to a glove-box. rundum crucible under dry argon.
[
1] D. Trinschek, M. Jansen, Angew. Chem. 111, 234 [5] F. Bernhardt, R. Hoppe, Z. Anorg. Allg. Chem. 619,
(
1999); Angew. Chem. Int. Ed. 38, 133 (1999).
540 (1993).
[
2] A. Möller, Z. Anorg. Allg. Chem. 627, 2625 (2001).
3] W. Burow, J. Birx, F. Bernhardt, R. Hoppe, Z. Anorg.
Allg. Chem. 619, 923 (1993).
[6] M. Sofin, M. Jansen Z. Anorg. Allg. Chem. 627,
[
2115 (2001).
[
4] F. Bernhardt, R. Hoppe, R. K. Kremer Z. Anorg.
Allg. Chem. 620, 187 (1994).
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