Synthesis and crystal structure of Rb3AgO2

Article abstract of DOI:10.1002/1521-3749(200211)628:11<2500::AID-ZAAC2500>3.0.CO;2-L

Rb₃AgO₂ was prepared via the azide/nitrate route. Stoichiometric mixtures of the precursors (Ag₂O, RbN₃ and RbNO₃) were heated in a special regime up to 450°C and annealed at this temperature for 50 h in silver crucibles. Single crystals have been grown by subsequent annealing of the as prepared powder at 450°C for 500 h in silver crucibles, which were sealed in glass ampoules under dried Ar. According to the X-ray analysis of the crystal structure (P2₁2₁2₁, Z = 16, a = 12.800(1), b = 12.848(1), c = 14.329(1) A, 6566 independent reflections, R(all) = 0.0795, R_w(all) = 0.0218), Rb₃AgO₂ is isostructural with K₃AgO₂. The structure can be derived from the fluorite structure type. Silver is linearly coordinated by oxygen atoms, while Rb has pseudo-tetrahedral coordination. The crystal under investigation was composed of four twin individuals.

Full text of DOI:10.1002/1521-3749(200211)628:11<2500::AID-ZAAC2500>3.0.CO;2-L

Synthesis and Crystal Structure of Rb3AgO2
M. Sofin, K. Friese, J. Nuss, E. M. Peters, and M. Jansen*
Stuttgart, Max-Planck-Institut für Festkörperforschung
Received June 18th, 2002.
Dedicated to Professor Dieter Fenske on the Occasion of his 60th Birthday
Abstract. Rb3AgO2 was prepared via the azide/nitrate route. Stoi-
chiometric mixtures of the precursors (Ag2O, RbN3 and RbNO3)
were heated in a special regime up to 450 °C and annealed at this
temperature for 50 h in silver crucibles. Single crystals have been
grown by subsequent annealing of the as prepared powder at
450 °C for 500 h in silver crucibles, which were sealed in glass am-
poules under dried Ar. According to the X-ray analysis of the crys-
Rw(all) ϭ 0.0218), Rb3AgO2 is isostructural with K3AgO2. The
structure can be derived from the fluorite structure type. Silver is
linearly coordinated by oxygen atoms, while Rb has pseudo-tetra-
hedral coordination. The crystal under investigation was composed
of four twin individuals.
tal structure (P212121, Z ϭ 16, a ϭ 12.800(1), b ϭ 12.848(1), c ϭ
Keywords: Silver; Rubidium silver oxide; Crystal structure; Twin-
ning; Azide/nitrate route.
˚
14.329(1) A, 6566 independent reflections, R(all)
ϭ
0.0795,
Synthese und Kristallstruktur von Rb3AgO2
˚
Inhaltsübersicht. Rb3AgO2 wurde über die Azid/Nitrat-Route dar-
gestellt. Stöchiometrische Gemenge der Edukte (Ag2O, RbN3 und
RbNO3) wurden unter besonderer Temperaturführung bis 450 °C
aufgeheizt und bei dieser Temperatur 50 Stunden in Silbertiegeln
getempert. Durch nachträgliches Tempern des erhaltenen Pulvers
(450 °C, 500 h) in Silbertiegeln, die unter getrocknetem Ar in Glas-
ampullen eingeschmolzen waren, wurden Einkristalle erhalten.
Nach der Röntgenstrukturanalyse (P212121, Z ϭ 16, a ϭ 12,800(1),
b ϭ 12,848(1), c ϭ 14,329(1) A, 6566 unabhängige Reflexe,
R(alle) ϭ 0.0795, Rw(alle) ϭ 0.0227) ist Rb3AgO2 isotyp zu
K3AgO2. Die Struktur kann vom Fluorit-Typ abgeleitet werden.
Silber ist linear von Sauerstoffatomen koordiniert, während das
Rubidium eine pseudotetraedrische Umgebung aufweist. Der un-
tersuchte Kristall war systematisch verzwillingt und wurde über
vier Zwillingsindividuen beschrieben.
Introduction
are extremely sensitive to air and moisture, and turn black,
immediately, when exposed to humid air. The DTA/TG
analysis has shown that Rb3AgO2 starts melting at
ϳ620 °C.
Alkali metal oxoargenates(I) are known to form families of
the compositions AAg3O2 (A ϭ Li [1], Na [2]), AAgO (A ϭ
Li[3], Na[4], K [4, 5], Rb[4, 6, 7], Cs[4, 5, 7]), and A3AgO2
(A ϭ Na [3], K [8, 9]). Within each family the constitution of
the oxoargentate anion is uniformly determined by the Ag/O
ratio, and the degree to which the basic linear unit AgO2 is
condensed varies from isolated (A3AgO2) through oligom-
The crystal structure of the novel rubidium argenate,
which crystallises orthorhombic (P212121), was determined
from a crystal which showed systematic twinning as is al-
ready suggested by the observed pseudotetragonal metrics.
Four individuals have to be taken into account (see Table
1). The second individual results from the first through a
rotation by 90° around the crystallographic c-axis; the third
one is connected via a centre of symmetry, and the fourth
is the resulting rotoinversion by 90°. Of the four individuals
only the first three have significant volume fractions. Al-
though the sum of individual I and III already account for
90 % of the complete volume of the crystal the introduction
of individuals II and IV in the refinement process led to a
considerable improvement of the agreement factors (about
3 %) and thus confirmed the correctness of the description.
For further details of the measurement, structure deter-
mination and additional crystallographic data see Tables
1Ϫ3. Interatomic distances, coordination numbers (CN), ef-
fective coordination numbers (ECoN) and mean fictive
ionic radii (MEFIR) [11] for Rb3AgO2 are given in Table 4.
The difference between the Madelung part of lattice energy
eric [Ag4O4] (AAgO) to infinite-crosslinked 1ϱ[AgO2/3
]
(AAg3O2). Na3AgO2 and K3AgO2 show particularly close re-
lationships to the structures of the respective parent alkali
metal oxides. However, the cation ordering is significantly
different. Here we report on the synthesis and structure deter-
mination of the new homologue Rb3AgO2.
Results and Discussion
Rb3AgO2 can be readily prepared by the azide/nitrate route
[10] as a micro-crystalline powder. The colourless products
* Prof. Dr. M. Jansen
Max-Planck-Institut für Festkörperforschung
Heisenbergstraße 1
D-70569 Stuttgart
Fax: ϩ49-711-689 15 02
e-mail: m.jansen@fkf.mpg.de
2500
 WILEY-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002 0044Ϫ2313/02/628/2500Ϫ2504 $ 20.00ϩ.50/0 Z. Anorg. Allg. Chem. 2002, 628, 2500Ϫ2504

Synthesis and Crystal Structure of Rb3AgO2
2
˚
Table 1 X-ray and crystallographic data for Rb3AgO2 (293 K)
Table 3 Anisotropic thermal displacement parameters (in A )
for Rb3AgO2
Crystal data
Crystal system
Space group, Z
Lattice constants (from powder), A
Orthorhombic
P212121 (no 19), 16
a ϭ 12.800(1)
b ϭ 12.848(1)
c ϭ 14.329(1)
88.86
atom U11
U22
U33
U12
U13
U23
˚
Ag1
Ag2
Ag3
Ag4
Rb1
Rb2
0.0196(5)
0.0173(5)
0.0197(7)
0.0211(7)
0.0162(7)
0.035(1)
0.0206(4)
0.0222(6)
0.0217(5)
0.0207(6)
0.027(1)
Ϫ0.0003(5)
0.0010(6)
0.0006(5)
0.0007(6)
Ϫ0.018(1)
0.0060(8)
Ϫ0.0003(9)
0.0015(6)
Ϫ0.0011(8)
0.0008(6)
0.006(1)
Ϫ0.0004(7)
0.0012(6)
Ϫ0.0002(7)
0.0002(6)
Ϫ0.0043(9)
0.004(1)
0.0176(7)
0.0187(5)
0.0199(8)
0.039(1)
0.028(1)
Molar volume, cm3/mol
Calculated density, g/cm3
Crystal shape, color
Crystal size, mm
Data collection
Diffractometer
4.47
0.0286(8)
0.0406(7)
0.001(1)
irregular, colourless
0.2 x 0.1 x 0.1
Rb3
Rb4
Rb5
Rb6
Rb7
Rb8
Rb9
0.031(1)
0.038(1)
0.055(1)
0.025(1)
0.026(1)
0.0215(6)
0.024(1)
0.033(1)
0.045(1)
0.040(1)
0.031(1)
0.0209(8)
0.0223(8)
0.023(1)
0.0211(8)
0.024(1)
0.027(1)
0.013(8)
0.044(9)
0.022(7)
0.020(7)
0.029(7)
0.029(8)
0.019(6)
0.009(7)
0.032(1)
0.0320(9)
0.054(1)
0.031(1)
0.0242(9)
0.0218(7)
0.0228(9)
0.026(1)
0.0226(8)
0.025(1)
0.031(8)
0.050(10)
0.017(7)
0.048(9)
0.024(6)
0.040(8)
0.019(6)
0.048(9)
0.013(1)
Ϫ0.0170(9)
0.021(1)
Ϫ0.002(1)
Ϫ0.0076(9)
0.029(1)
Ϫ0.001(1)
0.0006(8)
0.0219(9)
Ϫ0.008(1)
Ϫ0.0003(8)
Ϫ0.0002(6)
0.0017(9)
Ϫ0.0002(8)
0.0006(8)
0.0024(8)
Ϫ0.004(7)
0.005(7)
Ϫ0.003(6)
0.003(7)
Ϫ0.003(6)
Ϫ0.008(7)
0.001(5)
STOE IPDS II
Graphite
MoKα, 0.71073
2.0 < 2Θ < 59.1
0.0025(9)
Ϫ0.0007(9)
0.001(1)
0.0001(8)
Ϫ0.0003(8)
Ϫ0.0030(8)
0.0001(8)
Ϫ0.006(6)
0.020(7)
Ϫ0.002(6)
0.010(7)
Ϫ0.006(5)
0.013(6)
Ϫ0.004(1)
0.0002(9)
Ϫ0.0002(9)
0.0018(8)
0.0005(9)
0.0007(8)
0.0029(8)
Ϫ0.002(7)
Ϫ0.008(8)
0.005(6)
Ϫ0.005(8)
0.001(6)
0.011(6)
Ϫ0.001(6)
0.005(7)
Monochromator
˚
Wavelength, A
2Θ range for data collection
h.k.l-range
Ϫ17 < h < 17, Ϫ17 < k < 17, Ϫ19
Rb10 0.025(1)
Rb11 0.024(1)
Rb12 0.0232(9)
< l < 19
Gauss [14]
0.2497, 0.6504
24749
6566
27.9
Absorption correction
Tmin, Tmax
O1
O2
O3
O4
O5
O6
O7
O8
0.041(8)
0.012(10)
0.045(9)
0.025(10)
0.016(7)
0.017(7)
0.031(8)
0.037(8)
Total no. reflection
Unique reflections
Absorption coefficient. µ (mmϪ1
F(000)
)
2784.0
Structure refinement
Structure solution
Structure refinement
Parameters refined
R(obs) (> 3σ)
0.004(6)
Ϫ0.016(6)
SHELXS97 [15]
Jana2000 [16]
221
Ϫ0.006(7)
0.0398
Rw(obs)
R(all)
Rw(all)
0.0218
0.0795
The most characteristic feature of the structure is the lin-
3Ϫ
ear AgO2
anion, with d(Ag-O) ranging from 2.00 to
0.0227
˚
¯
010 / 100 / 001
Twin matrix II
Twin matrix III
Twin matrix IV
Twin volume I
Twin volume II
Twin volume III
Twin volume IV
Extinction coefficient
2.04 A and O-Ag-O angles from 173.1° for Ag2 to 178.0°
for Ag1. These data, related to the silver(I) anion, are basi-
cally in agreement for Rb3AgO2, K3AgO2 [8] and Na3AgO2
[3]. Yet the Ag-O distances in K3AgO2 as reported in [8]
¯
¯
¯
¯
100 / 010 / 001
¯
010 / 100 / 001
0.39(2)
0.10(1)
0.48(1)
0.02(1)
0.0393(6)
˚
show a surprisingly wide spread from 1.91 to 2.10 A (dis-
˚
tances reported in the paper range from 1.95 to 2.12 A but
do not correspond to the given coordinates and lattice par-
ameters). These distances do not appear very convincing
and in particular a Ag-O bond length as short as 1.91 A is
Table 2 Atomic coordinates and isotropic displacement param-
eters for Rb3AgO2
˚
without precedence. Furthermore, the displacement param-
eters of some of the potassium atoms are non positive defi-
nite and the oxygen atoms were refined only isotropically.
One might imagine that the crystals of K3AgO2 were also
twinned, but that the twinning was not taken into account
during the structure refinement. In this context it is interest-
ing that a refinement of Rb3AgO2 without taking into con-
sideration the systematic twinning leads to a model in which
the Ag-O bond lengths also show a stronger variation (from
atom
x
y
z
Uiso
Ag1
Ag2
Ag3
Ag4
Rb1
Rb2
Rb3
0.9997(2)
0.2342(1)
0.9993(2)
0.2288(1)
0.2021(2)
0.9895(2)
0.1959(2)
0.9977(2)
0.2557(1)
0.9906(2)
0.2341(1)
0.3038(2)
0.0045(2)
0.1971(2)
0.17544(7)
0.9195(1)
0.85054(8)
0.5929(1)
0.1452(2)
0.4249(1)
0.3607(2)
0.0192(3)
0.0198(4)
0.0205(3)
0.0189(4)
0.0333(7)
0.0325(5)
0.0321(7)
Rb4
Rb5
Rb6
Rb7
Rb8
0.0685(2)
0.0057(2)
0.9805(2)
0.9874(2)
0.9474(1)
0.9168(2)
0.2127(1)
0.2846(2)
0.1997(2)
0.2497(2)
0.6281(1)
0.7272(1)
0.4944(1)
0.0075(1)
0.2443(1)
0.0386(6)
0.0498(7)
0.0287(6)
0.0235(6)
0.0219(4)
˚
1.98 to 2.09 A).
All AgO2 dumb-bells in Rb3AgO2 are oriented parallel
¯
(001), one half directing along [110] and one half along the
Rb9
Rb10
Rb11
Rb12
O1
O2
O3
O4
O5
0.2055(2)
0.7826(2)
0.2471(2)
0.7346(2)
0.610(1)
0.390(1)
0.349(1)
0.124(1)
0.387(1)
0.115(1)
0.339(1)
0.123(1)
0.0100(2)
0.9790(2)
0.9554(2)
0.0440(2)
0.390(1)
0.616(1)
0.146(1)
0.366(1)
0.401(1)
0.884(1)
0.347(1)
0.120(1)
0.0088(1)
0.0092(1)
0.2612(1)
0.2441(1)
0.823(1)
0.822(1)
0.917(1)
0.939(1)
0.143(1)
0.839(1)
0.607(1)
0.569(1)
0.0230(6)
0.0239(6)
0.0237(6)
0.0251(6)
0.028(5)
0.036(6)
0.028(4)
0.031(5)
0.023(4)
0.029(5)
0.023(4)
0.032(5)
[110] direction (Fig. 1). This is different to Na3AgO2, where
the AgO2 dumb-bells are arranged along the [001] axis and
¯
point alternatively along the [120] and [120] direction.
The Rb atoms are coordinated pseudotetrahedrally by
oxygen. An exception is Rb5 which has only three nearest
neighbours, for this atom the fourth neighbour is shifted
O6
O7
O8
˚
and is located at a considerably large distance of 3.92(2) A.
Some of the Rb-O distances are rather small with values
˚
below 2.7 A. These, however, are comparable to other short
(MAPLE) [12] of Rb3AgO2 and that calculated for the sum
of the binary oxides (see Table 5) is satisfactorily low
(0.98 %).
Rb-O distances as observed in literature e.g. in Rb2PbO2
[17] or Rb2TeO3 [18]. The cation cation distances are in the
range of 3.3-3.8 A, which is quite common to that of other
˚
Z. Anorg. Allg. Chem. 2002, 628, 2500Ϫ2504
2501

M. Sofin, K. Friese, J. Nuss, E. M. Peters, M. Jansen
˚
Table 4 Interatomic distances (in A). coordination numbers (CN). effective coordination numbers (EcoN) and mean fictive ionic radii
(MEFIR) [11] for Rb3AgO2
atom
O1
O2
O3
O4
O5
O6
O7
O8
C.N.
ECoN
MEFIR
Ag1
Ag2
Ag3
Ag4
Rb1
Rb2
Rb3
Rb4
Rb5
Rb6
Rb7
Rb8
2.02(2)
2.03(2)
2
2
2
2
4
4
4
4
3
4
4
4
4
4
4
4
2.0
2.0
2.0
2.0
3.4
3.8
3.0
3.2
3.0
3.7
3.8
4.0
3.8
3.9
3.5
3.8
0.62
0.63
0.61
0.63
1.34
1.42
1.30
1.39
1.44
1.52
1.47
1.46
1.51
1.50
1.50
1.53
2.04(2)
2.01(2)
2.00(1)
2.68(1)
2.03(2)
2.04(2)
2.75(2)
2.03(2)
2.79(2)
3.06(2)
2.98(2)
2.69(2)
3.22(2)
3.02(2)
2.83(2)
3.31(1)
3.07(2)
3.28(2)
2.83(2)
2.97(2)
2.99(2)
2.65(2)
3.10(2)
2.85(2)
2.97(2)
2.73(2)
2.93(2)
2.94(2)
2.81(1)
2.83(1)
3.23(2)
2.92(2)
3.04(2)
2.87(1)
2.83(1)
2.85(1)
3.12(2)
2.91(2)
3.00(2)
2.87(2)
2.95(2)
2.86(2)
Rb9
3.15(2)
2.94(2)
2.89(2)
3.36(2)
Rb10
Rb11
Rb12
C.N.
ECoN
MEFIR
2.99(1)
2.91(2)
2.86(2)
3.02(2)
7
6.6
3.19(2)
7
6.2
2.90(1)
6
5.9
2.89(1)
6
6.0
7
6.5
1.46
7
6.3
1.43
7
6.5
1.45
8
6.8
1.47
1.47
1.46
1.41
1.40
Table 5 Madelung part of lattice energy (MAPLE) for Rb3AgO2
(in kcal/mol)
Viewing along [001] one can distinguish two different
types of chains of edge sharing tetrahedra. One type is oc-
cupied exclusively by rubidium (Rb5-Rb12, Fig. 1 top), the
second one contains rubidium and silver in equal amounts
(Rb1-Rb4 and Ag1-Ag4, Fig. 1 bottom). The ordering se-
quence along [001] in the mixed rows is -Ag-Ag-Rb-Rb-
(Fig. 2; right).
Because of the strong preference for a linear twofold co-
ordination silver is shifted from the centre to the edge of
the tetrahedra. The rubidium atoms are necessarily influ-
enced by these shifts and move in directions of neighbour-
ing octahedral sites. As a consequence, the tetrahedral sites
of the fluorite parent structure are now empty (Fig. 2, right)
in the partial structure discussed.
atom
binary
ternary
Σ∆a)
Ag1
Ag2
Ag3
Ag4
Rb1
Rb2
Rb3
Rb4
Rb5
Rb6
Rb7
Rb8
Rb9
Rb10
Rb11
Rb12
O1
O2
O3
O4
O5
O6
O7
O8
132.5b)
132.5
132.5
132.5
100.2c)
100.2
100.2
100.2
100.2
100.2
100.2
100.2
100.2
100.2
100.2
100.2
453.8b)
453.8
372.5c)
372.5
372.5
372.5
372.5
372.5
137.6
135.9
132.0
132.5
118.0
120.1
113.8
106.4
91.3
89.2
95.7
98.9
88.1
ϩ5.0
ϩ3.2
Ϫ0.7
Ϫ0.1
ϩ17.8
ϩ19.8
ϩ13.6
ϩ6.2
Ϫ8.9
Ϫ11.1
Ϫ4.5
Ϫ1.3
Ϫ12.1
ϩ0.6
Ϫ14.1
Ϫ3.2
Ϫ69.0
Ϫ74.9
ϩ13.1
ϩ1.3
ϩ16.7
ϩ24.2
ϩ14.6
ϩ14.9
100.8
86.1
96.9
A similar mode of substitution can also be applied to
derive the structures of K3CuO2 and Na3AgO2 from the
respective alkali metal oxides.
384.8
378.9
385.7
373.9
389.3
396.7
387.2
387.4
Experimental
Starting materials for the preparation of Rb3AgO2 were rubidium
nitrate (Johnson Matthey, 99 %), rubidium azide and silver oxide
Ag2O (Johnson Matthey, 99 %). Rubidium azide was synthesised
[13] from aqueous HN3 and rubidium carbonate (Johnson Mat-
they, 99 %). The starting materials (RbN3, RbNO3 and Ag2O) were
mixed in the required ratio according to the equation
Σ
4875.0
4827.3
∆ ϭ Ϫ47.7 (Ϫ0.98 %)
a) ternary-binary: MAPLE(Rb3AgO2) Ϫ 1.5 MAPLE(Rb2O) Ϫ 0.5 MAPLE-
(Ag2O)
b) from Ag2O
c) from Rb2O
5 RbN3 ϩ RbNO3 ϩ Ag2O ϭ 2 Rb3AgO2 ϩ 8 N2,
complex alkali transition metal oxides like Na2RbAuO2 [19]
or Cs3AuO2 [20].
The Rb3AgO2 structure can be derived from that of
Rb2O (anti CaF2 type) by substituting silver for one fourth
of the rubidium atoms which are located at the tetrahedral
ground in a planet ball mill, pressed in pellets under 105 N, dried
under vacuum (10Ϫ3 mbar) at 150 °C for 12 h, and placed under
argon in a tightly closed steel container provided with a silver inlay.
In a flow of dry argon the following temperature treatment was
applied: 25Ǟ260 °C (100 K/h); 260Ǟ380 °C (5 K/h); 380Ǟ450 °C
(50 K/h) followed by subsequent annealing for 50 h at 450 °C.
sites of the fcc packing of oxygen atoms: Rb3AgO2
־
Rb4O2.
2502
Z. Anorg. Allg. Chem. 2002, 628, 2500Ϫ2504

Synthesis and Crystal Structure of Rb3AgO2
Fig. 2 Sections of the crystal structure of Rb3AgO2, showing edge
sharing edge sharing tetrahedra, all centred by rubidium (left), with
silver and rubidium shifted off-centre (right).
˚
Table 6 Powder diffraction data of Rb3AgO2 (d > 2.25 A). Results
of a profile fit using the local parameters from the single crystal
investigation.
˚
˚
h
k
l
d/A
I/I0 (%)
h
k
l
d/A
I/I0 (%)
1
0
1
0
2
1
2
1
2
0
2
2
1
3
3
0
2
1
2
3
2
1
2
0
3
1
2
0
4
0
2
3
3
0
0
2
4
1
4
1
3
1
1
0
2
0
2
1
2
1
2
0
2
1
0
1
2
0
2
1
0
3
3
3
1
2
1
2
4
0
3
3
2
0
4
2
0
0
4
1
3
1
1
2
2
1
1
0
0
1
1
2
2
0
3
1
1
3
3
3
3
2
0
2
1
4
1
4
3
0
0
3
2
2
3
1
4
4
1
0
0
3
3
7.6626
6.2571
6.2518
5.8619
5.8434
5.7413
5.7288
5.3294
5.3192
4.7829
4.7729
4.5338
4.2257
4.0892
3.8966
3.8328
3.8278
3.6718
3.6685
3.6658
3.5592
3.5331
3.4543
3.4505
3.4496
3.3316
3.2882
3.2120
3.2000
3.1885
3.1875
3.1839
3.1820
3.1342
3.1286
3.1258
3.1230
3.1154
3.1051
3.0940
3.0886
2.2
0.1
0.1
0.1
0.3
0.2
0.7
0.9
0.4
1.5
1.3
1.0
5.4
0.1
0.3
0.3
0.4
0.7
0.4
0.7
0.1
1.1
0.5
0.1
1.8
0.1
0.6
24.7
30.9
0.7
5.8
1.0
0.1
1.2
0.2
0.1
0.1
2.3
12.8
28.7
18.1
1
1
2
4
3
0
1
2
3
4
2
2
4
1
0
1
3
2
4
4
1
3
1
4
2
3
3
2
3
1
5
0
4
0
4
3
0
1
4
4
5
4
2
1
1
3
4
4
3
2
1
4
2
2
0
3
1
1
4
2
0
4
4
2
3
1
3
4
3
2
5
1
5
3
4
0
0
1
0
1
4
0
1
4
4
1
1
2
2
3
3
2
1
4
1
5
4
5
4
2
2
3
3
0
5
0
5
3
1
4
4
1
1
2
2
4
4
5
6
6
4
0
3
3.0443
3.0391
3.0372
3.0347
2.9575
2.9309
2.8570
2.8540
2.8513
2.8490
2.8148
2.8107
2.8087
2.7965
2.7476
2.7325
2.6829
2.6648
2.6596
2.6585
2.6093
2.5661
2.5640
2.5634
2.5629
2.5541
2.5259
2.5248
2.5230
2.4813
2.4730
2.4187
2.4136
2.3914
2.3865
2.3789
2.3479
2.3476
2.3463
2.2670
2.2563
9.8
2.2
8.7
1.3
16.6
0.1
0.5
0.2
3.4
0.8
1.6
100.0
0.5
1.0
1.0
22.0
0.3
5.2
4.0
0.3
0.4
0.4
2.1
1.4
1.2
24.2
1.0
6.1
1.3
10.4
7.9
1.2
0.5
1.6
2.3
3.6
0.8
0.7
1.0
24.5
3.8
Fig. 1 Crystal structure of Rb3AgO2, emphasising the chains of
edge sharing tetrahedra fully occupied by rubidium (top), and with
rubidium and silver (bottom); see text.
The obtained colourless powder was sealed in glass ampoules under
argon atmosphere and all following manipulations were performed
in inert atmospheres of purified argon. Single crystals have been
grown by subsequent annealing of the as prepared powder at
450 °C for 500 h in silver crucibles, which were sealed in glass am-
poules under dried Ar. The X-ray investigation on a powder sample
was performed on a STOE Stadi P diffractometer with Cu-Kα1
˚
radiation (λϭ1.54178 A) at room temperature using a position sen-
sitive detector and a curved germanium monochromator. The pow-
der diffraction experiment confirms he pureness of the sample
(Table 6). Details on single crystal diffraction experiments are given
in Table 1.
Thermal analyses were carried out using a DTA/TG device (STA
409, Netzsch) coupled with a quadrupole mass spectrometer
(QMG 421, Balzers). The sample (m ϭ 46.2 mg) was heated at a
rate of 10 K/min in a corundum crucible under dry argon.
Z. Anorg. Allg. Chem. 2002, 628, 2500Ϫ2504
2503

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[13] A. Petrikaln, Z. Phys. 1926, 37, 610.
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1968, A24, 351.
[15] G. Sheldrick, University of Göttingen, Göttingen, 1997.
[16] V. Petricek, M. Dusek, Institute of Physics, Academy of the
Czech Republic, Praha, 2000.
[17] K. P. Martens, R. Hoppe, Z. Anorg. Allg. Chem., 1978, 440, 81.
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2504
Z. Anorg. Allg. Chem. 2002, 628, 2500Ϫ2504