Double complex salts with [Ru(NH3)5Cl]2+ cation and [OsCl6]2- anion: Synthesis and properties. Crystal structure of [Ru(NH3)5Cl]2[OsCl 6]Cl2

Article abstract of DOI:10.1134/S0036023610090032

Double complex salts [Ru(NH₃)₅Cl][OsCl₆] and [Ru(NH₃)₅Cl]₂[OsCl₆]Cl ₂ were prepared and characterized. An X-ray diffraction study showed that [Ru(NH₃)₅Cl][OsCl₆] is isostructural to the previously synthesized [Rh(NH₃)₅Cl][OsCl₆]. The structure of [Ru(NH₃)₅Cl]₂[OsCl ₆]Cl₂ was solved by X-ray diffraction (a = 11.1849(8) ?, b = 7.9528(6) ?, c = 13.4122(9) ?; β = 99.765(2)°; V= 1175.75 ?³; space group C2/m; Z = 2). Thermolysis of the compounds under hydrogen and helium was studied. According to X-ray diffraction, nanosized metallic powders of the corresponding alloys are formed as the final products of thermolysis. The compositions of the obtained solid solutions are consistent with the phase diagram of the Ru-Os system.

Full text of DOI:10.1134/S0036023610090032

ISSN 0036ꢀ0236, Russian Journal of Inorganic Chemistry, 2010, Vol. 55, No. 9, pp. 1347–1351. © Pleiades Publishing, Ltd., 2010.
Original Russian Text © I.V. Korol’kov, S.A Martynova, K.V. Yusenko, S.V. Korenev, 2010, published in Zhurnal Neorganicheskoi Khimii, 2010, Vol. 55, No. 9, pp. 1429–1433.
SYNTHESIS AND PROPERTIES
OF INORGANIC COMPOUNDS
Double Complex Salts with [Ru(NH3)5Cl]2+ Cation
and [OsCl6]2– Anion: Synthesis and Properties.
Crystal Structure of [Ru(NH3)5Cl]2[OsCl6]Cl2
I. V. Korol’kov, S. A Martynova, K. V. Yusenko, and S. V. Korenev
Nikolaev Institute of Inorganic Chemistry, Siberian Division, Russian Academy of Sciences,
pr. Akademika Lavrent’eva 3, Novosibirsk, 630090 Russia
Received March 15, 2009
Abstract—Double complex salts [Ru(NH3)5Cl][OsCl6] and [Ru(NH3)5Cl]2[OsCl6]Cl2 were prepared and
characterized. An Xꢀray diffraction study showed that [Ru(NH3)5Cl][OsCl6] is isostructural to the previously
synthesized [Rh(NH3)5Cl][OsCl6]. The structure of [Ru(NH3)5Cl]2[OsCl6]Cl2 was solved by Xꢀray diffracꢀ
tion (
a
= 11.1849(8) Å,
b
= 7.9528(6) Å,
c
= 13.4122(9) Å;
β
= 99.765(2)°; V C2/m;
= 1175.75 Å3; space group
Z
= 2). Thermolysis of the compounds under hydrogen and helium was studied. According to Xꢀray diffracꢀ
tion, nanosized metallic powders of the corresponding alloys are formed as the final products of thermolysis.
The compositions of the obtained solid solutions are consistent with the phase diagram of the Ru–Os system.
DOI: 10.1134/S0036023610090032
A recent trend for combining subtle investigations obtain solid solutions of refractory metals under rather
of fundamental properties and structures of phases and mild conditions. Previously, we demonstrated the posꢀ
compounds with the practical use of the results in varꢀ sibility of preparing equilibrium solid solutions of
ious multipurpose industrial processes can be noted in refractory metals by thermolysis of double complex
chemistry and chemical engineering.
salts (DCS), for example, Re0.5Os0.5 [4], Ru0.33Re0.67
[5], and Ru0.25Re0.75 [6].
The purpose of this work is the synthesis and invesꢀ
tigation of the DCS containing Ru and Os, production
Osmium, which is the heaviest metal (density
22.6 g/cm3), is also among the hardest and highꢀmeltꢀ
ing metals. The content of osmium in the Earth crust
is only
5
10–6 wt %; this is a scattered and expensive
×
of solid solutions RuxOs1 – by their thermolysis, and
x
metal; therefore, it is used in industry only there where
minor metal consumption can bring about a considerꢀ
able effect, for example, to produce premium wearꢀ
resistant alloys and as a catalyst. Osmium catalysts are
superior to platinum catalysts for hydrogenization of
organic compounds [1]. Ruthenium and osmium solid
solutions are used as especially strong construction
materials [2].
analysis of the structural features of metallic phases in
the ruthenium–osmium system.
EXPERIMENTAL
The starting compounds used to produce DCS
were Na2[OsCl6] and [Ru(NH3)5Cl]Cl2 synthesized by
published procedures [7, 8].
Fusion or highꢀtemperature annealing of finely for
preparing homogeneous samples of construction
alloys dispersed pure metal powders are used most
often for preparing homogeneous samples of conꢀ
struction alloys. This allows one to produce powders
over the whole range of compositions. Drawbacks of
this method are high annealing temperature (the meltꢀ
ing points of pure osmium and ruthenium are 3033
[Ru(NH3)5Cl][OsCl6] (I). Hot (70–80°С) soluꢀ
tions of [Ru(NH3)5Cl]Cl2 (0.1 g, 3.42
water (30 mL) and Na2[OsCl6] (0.16 g, 3.5
×
10–4 mol) in
×
10–4 mol)
in water (40 mL) were mixed. This immediately gave a
redꢀbrown precipitate, which was collected, after 3 h,
on a fineꢀporous glass filter under vacuum, washed
with water and acetone, and dried in air. IR, cm–1:
3289 s, 3230 s, 3179 m ( (NH3)); 1613 (δd(NH3));
ν
and 2234 С, respectively) and long time (from several
°
1309 s (δs(NH3)); 786 (ρr(NH3)); 446 ( (RuN)). Yield
ν
days to several weeks) needed to reach the equilibrium.
A characteristic feature of osmium is the ability to be
oxidized by air oxygen after vacuum sintering of its
finely dispersed powder; this complicates the proceꢀ
dure of investigation of the formation of solid solutions
by conventional methods [3].
85ꢀ90%.
Anal. calcd. (%): Ru + Os,46.70.
Found (%): Ru + Os, 47.00 0.30
[Ru(NH3)5Cl]2[OsCl6]Cl2 (II). Finely crystalꢀ
line [Ru(NH3)5Cl]Cl2 (0.13 g, (4.4
10–4 mol) was covꢀ
10–4 mol)
.
×
Thermolysis of the coordination compounds conꢀ ered by a solution of Na2[OsCl6] (0.12 g, 2.57
×
taining several metals can be successfully used to in 0.1 M HCl (40 mL) and allowed to stand in the
1347

1348
KOROL’KOV et al.
Table 1. Crystallographic characteristics of the complexes
dark for 5 days. After this period, the starting
[Ru(NH3)5Cl]Cl2 completely dissolved, and dark
claretꢀcolored crystals precipitated from the solution.
The precipitate was collected on a porous glass filter,
washed with water and acetone, and dried in air. IR,
[Ru(NH3)5Cl]2[OsCl6]Cl2 and [Ru(NH3)5Cl][OsCl6]
Formula [Ru(NH3)5Cl]2[OsCl6]Cl2 [Ru(NH3)5Cl][OsCl6]
a
, Å
, Å
, Å
deg
, Å3
11.1849(8)
7.9528(6)
13.4122(9)
99.765(2)
1175.75
11.593(2)
8.318(1)
15.234(3)
90.707(2)
1468.97
cm–1: 3282 s, 3163 s, 3087 m, (
ν
(NH3)); 1615
δd(NH3)); 1305 s (δs(NH3)); 786 (ρr(NH3)); 448
ν(RuN)). Yield 85–90%.
b
(
(
c
β
,
Anal. calcd. (%): Ru + Os, 42.80.
Found (%): Ru + Os, 42.60 0.30.
V
Space group
C
2/
m
P
21/
m
IR spectra were recorded on a Scimitar FTS 2000
FT IR spectrometer in the 400–4000 cm–1 range (KBr
pellets). The sum of the metals was quantified by heatꢀ
ing an exact weighed portion of DCS under hydrogen
Z
2
4
FW
917.18
2.564
624.62
2.824
ρ(calcd.),
or helium to 500 С.
°
g/cm3
The thermal properties were studied on a Qꢀ1000
derivatograph. A ~100ꢀmg sample of the compound
was placed into a quartz crucible without a lid and
heated at a rate of 10 K/min in a helium flow
(150 mL/min).
Table 2. Atom coordinates in [Ru(NH3)5Cl]2[OsCl6]Cl2 and
equivalent thermal parameters
Atom
x
/
a
y
/
b
z
/
c
U
eq, Å2
XꢀRay diffraction analysis of polycrystalline DCS
was carried out on a DRONꢀ3M diffractometer (Cu
K
α
Os
0
0
0
0
0.5
0.00870(3)
radiation, Ni filter,
2 = 5°–60°). All the synthesized
θ
Ru
0.32634(2)
0.19796(1) 0.01015(4)
0.09696(4) 0.0162(1)
samples were single phases.
XꢀRay diffraction analysis of the metallic thermolꢀ
ysis products was carried out on a DRONꢀSEIFERTꢀ
Cl(1) 0.13459(5)
Cl(2)
Cl(3) –0.01036(5) 0
Cl(4) 0.21094(5)
Cl(5) 0.17814(5) 0.5
0
0.29289(7) 0.5
0.0169(1)
0.32307(4) 0.0155(1)
0.52162(4) 0.0162(1)
0.12400(4) 0.0158(1)
RM4 diffractometer (Cu
K
radiation, Ni filter,
2θ =
α
5°–160°) at room temperature under atmospheric
pressure. The products were triturated in heptane and
the suspension was applied onto the polished side of a
standard quartz cell. The samples thus obtained were
0
~100 m thick layers. A polycrystalline silicon sample
µ
N(1)
N(2)
N(3)
0.3853(1) 0.1882(2) 0.1056(1) 0.0163(3)
0.2653(1) 0.1850(2) 0.2903(1) 0.0151(3)
prepared in a similar way was used as the reference.
The Xꢀray diffraction patterns were indexed by analꢀ
ogy with Xꢀray diffraction patterns of pure metals [9].
Using the PowderCell 2.4 program [10] (the peak proꢀ
files were fitted by an asymmetric Lorentz function,
0.5001(2)
0
0.2877(2) 0.0183(4)
2
θ
= 30°–150°), the unit cell parameters (UCP) were
refined.
Single crystal Xꢀray diffraction analysis of II (UCP
Table 3. Selected interatomic distances (d) and bond angles
(ω) for [Ru(NH3)5Cl]2[OsCl6]Cl2*
Bond
d
, Å
Angle
ω
, deg
refinement and diffraction reflection intensity meaꢀ
surement) were carried out on a BRUKER X8APEX
Os–Cl(2) 2.3293(6)
Os–Cl(3) 2.3561(6)
Os–Cl(4) 2.3278(6)
Cl(3)OsCl(4)
N(3)RuN(1)
N(1)RuN(1)#
89.94(2)
89.18(6)
89.90(8)
diffractometer (Mo
mator, CCD detector, room temperature,
K radiation, graphite monochroꢀ
α
θ
= 3.08°–
32.55°, 2251 experimental reflections). The crystal
structure was refined in the fullꢀmatrix approximation
Ru–N(1) 2.1181(15) N(1)RuN(2)# 179.10(6)
for 2228 independent reflections to
reflections and = 0.0152 for the reflections with
. The hydrogen atoms were specified geometriꢀ
R = 0.0154 for all
R
I >
Ru–N(2) 2.1094(14) N(3)RuN(2)
91.37(6)
90.82(6)
88.46(8)
179.41(6)
90.40(4)
89.06(4)
2σ(I)
Ru–N(3) 2.105(2)
Ru–Cl(4) 2.3344(6)
N(1)RuN(2)
N(2)#RuN(2)
N(3)RuCl(1)
N(1)RuCl(1)
N(2)RuCl(1)
cally in idealized positions. The UCP are summarized
in Table 1, atom coordinates and thermal vibrations
are given in Table 2, and the interatomic distances and
bond angles are given in Table 3.
RESULTS AND DISCUSSION
* Symmetry operations used for generation of equivalent atoms: # x,
–y – 1, z.
Synthesis. Due to the low solubility and high therꢀ
modynamic stability of the complex ions, all of the
RUSSIAN JOURNAL OF INORGANIC CHEMISTRY Vol. 55 No. 9 2010

DOUBLE COMPLEX SALTS
, %
exo
1349
m
(а)
2–
TG
[OsCl ]
6
100
90
80
70
60
50
x
DTA
–
Cl
0
z
40
y
100 150 200 250 300 350 400 450 500 550 600
T, °C
m, %
(b)
exo
100
2+
TG
[Ru(NH ) Cl]
3 5
Fig. 1. General view of the [Ru(NH ) Cl] [OsCl ]Cl
2
90
80
70
60
50
40
3 5
2
6
DTA
structure along the у axis.
obtained DCS are formed from aqueous solutions in
high yields. It was found by powder Xꢀray diffraction
that product I was a single phase. The phase composiꢀ
tion of product II depends on the conditions of synꢀ
thesis. After keeping the starting components in
hydrochloric acid for 3 days, the target product conꢀ
tained (according to powder Xꢀray diffraction data)
100
200
300
T, °C
400
about 20% of
kept for 5 days, the residual
I
as an impurity, and after the system was
was completely conꢀ
I
verted to complex II. The nature of equilibria in the
formation of phases of this type from aqueous soluꢀ
tions was considered previously [11].
Fig. 2. Weightꢀloss TG and DTA curves recorded under
helium (10 K/min) for (a) [Ru(NH ) Cl][OsCl ], (b)
3 5
6
[Ru(NH ) Cl] [OsCl ]Cl .
3 5
2
6
2
Crystal structure of salts I and II. According to
powder and single crystal Xꢀray diffraction, compound
II is isostructural to the series of DCS
[MI(NH3)5Cl]2[MIICl6]Cl2, where MI = Rh, Ir, Co;
MII = Re, Os, Ir, Pt [12]. The interatomic distances
within the coordination polyhedra do not differ from
these distances in other salts containing the same
complex ions. The Os–Cl bond lengths in the complex
anion are 2.328–2.356 Å, those in the complex cation
are: (Ru–N)avg, 2.111; Ru–Cl, 2.334 Å. The metal–
metal distances also do not differ from the distances
characteristic for this series of isostructural comꢀ
pounds. The shortest Ru···Os distance is 5.773 Å. The
Thermal decomposition. Decomposition of comꢀ
plex under helium includes several poorly separated
I
stages, as indicated by the DTA curve. The decompoꢀ
sition is mainly completed at 380°С, the weight loss
being 1.7% greater than the theoretical value. The
remaining mass gradually decreases on further heating
to 540°С. This process remains uninterpreted as yet.
The pattern of decomposition of II under helium is
simpler: oneꢀstage decomposition starts at 300°С and
ends at 380°С. The weight loss nearly corresponds to
the formation of the sum of metals (Fig. 2). As noted
previously, decomposition processes in a hydrogen
atmosphere occur faster; this is also true for these
compounds. Thus, the temperatures for preparating
metallic solid solutions are about 1/5 of the melting
points of pure metals.
general view of the structure along the
in Fig. 1.
y axis is shown
The UCP of complex
I were refined by powder
Xꢀray diffraction data using fullꢀprofile analysis. The
structure [Rh(NH3)5Cl][OsCl6] described previously
[13] was used as the model. According to Xꢀray difꢀ
Thermolysis products. Singleꢀphase solid solutions
are formed as the final products of decomposition of
fraction data,
15.2344(4) Å;
a
= 11.5931(4)
Å, b = 8.3181(3) Å, c =
β
= 90.707(4)°; V
= 1469 Å3; space group DCS under both helium and hydrogen. For
I, this is
P21/m;
Z
=4.
Ru0.5Os0.5 and for II, this is Ru0.67Os0.33.
RUSSIAN JOURNAL OF INORGANIC CHEMISTRY Vol. 55 No. 9 2010

1350
KOROL’KOV et al.
Table 4. Crystallographic data for metallic phases in the Ru–Os systems and conditions for their preparation
Composition Preparation conditions , Å
a
,
c
V/Z
, Å3
Ru
Reference
2.7058*
4.2819
13.575
13.54
13.64
13.71
13.73
13.73
13.74
13.768
13.77
13.81
13.98
[9, no. 6ꢀ663]
Ru0.88Os0.12
[16]
Alloying at 2000°C, vacuum
Alloying at 2000°C, vacuum
[Ru(NH3)5Cl]2[OsCl6]Cl2, 650
[Ru(NH3)5Cl]2[OsCl6]Cl2, 650
Alloying at 2000°C, vacuum
2.705
4.274
Ru0.74Os0.26
[16]
2.710
4.288
Ru0.67Os0.33
°
°
C, H2, annealing for 5 h
C, He, 1 h
2.714(2)
4.297(3)
[
This work
Ru0.67Os0.33
This work
]
2.716(2)
4.298(3)
[
]
Ru0.56Os0.44
[16]
2.716
4.297
Ru0.5Os0.5
[Ru(NH3)5Cl][OsCl6], 650
[Ru(NH3)5Cl][OsCl6], 650
Alloying**
°
C, H2, annealing for 5 h
C, He, 1 h
2.716(2)
4.302(3
[
This work
Ru0.5Os0.5
This work
]
]
°
2.718(2)
4.304(3)
[
Ru0.5Os0.5
[15]
2.719*
4.302
Ru0.32Os0.68
[16]
Alloying at 2000°C, vacuum
Reference
2.721
4.308
Os
2.7341*
4.3197
[9, no. 6ꢀ662]
Notes: * The error of determination of the parameters is not indicated in the cited study.
** The exact temperature and alloying conditions are not reported.
The phase diagram of the Ru–Os system [14] is our data on total metal contents, this confirms the
characterized by a continuous series of hexagonal solid composition of the obtained phases: Ru0.5Os0.5 and
solutions. The volume per atom for the solid solutions Ru0.67Os0.33
.
decreases in an additive fashion on increase in the Ru
content with simultaneous decrease in the melting
point. The UCP values and the melting points of the
pure components reported in [14] are somewhat
greater than the data of [15] and [16]. This may be due
to different purities of the initial metals and differenct
accuracies of determination of the UCP. Generally,
the solid solutions of Os and Ru have not been adeꢀ
quately studied. We were able to find only several menꢀ
tions of the crystallographic data concerning this sysꢀ
tem in the literature. These data for Ru–Os alloys
known in the literature are summarized in Table 4.
The points calculated from published data and
obtained in this work are adequately fitted by secondꢀ
order polynomial: y = 13.57 + 0.30x
+ 0.10x2. The negꢀ
ative deviation from the linearity is not more than
0.6%; that is the Rutgers rule of the linear dependence
of the volume per atom in a solid solution on the comꢀ
position is closely obeyed. Note that the UCP of the
thermolysis products that we studied correlate with the
UCP of real alloys. For example, the UCP for the
phase Ru0.5Os0.5 that we obtained at 650
atmosphere ( = 2.718(2), = 4.304(3) Å) and the UCP
of the Ru0.5Os0.5 phase obtained previously [15] by
alloying at 2000 С ( = 2.719 = 4.302
Thus, DCS Ru(NH3)5Cl][OsCl6
°С in a He
a
c
°
a
Å,
c
Å).
For analysis of a binary metallic system, it is conveꢀ
nient to use the curve for the volume per atom (
V
/
Z
) as
[
]
and
a function of the solid solution composition (Retgers [Ru(NH3)5Cl]2[OsCl6]Cl2 have been synthesized. It has
curve). For the Ru–Os system, this curve was conꢀ been shown that their thermolysis under helium and
structed from published data [9, 15, 16] and our results hydrogen at 600–650°С is accompanied by the formaꢀ
(Fig. 3). For better understanding, it is recommended tion of nanocrystalline singleꢀphase metallic powders
to consider Fig. 3 simultaneously with Table 4. The Ru0.5Os0.5 and Ru0.67Os0.33. Their V/Z characteristics
points that we obtained (pointed to by arrows with are well correlated with the characteristics of alloys of
indication of the precursor DCS and thermolysis conꢀ similar composition reported in the literature. It has
ditions) are well correlated with characteristics of been found that [Ru(NH3)5Cl]2[OsCl6]Cl2 is isostrucꢀ
analogous samples obtained by alloying. Together with tural to a large series of DCS with the general formula
RUSSIAN JOURNAL OF INORGANIC CHEMISTRY Vol. 55 No. 9 2010

DOUBLE COMPLEX SALTS
1351
3
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ACKNOWLEDGMENTS
The authors are grateful to Candidate of Physics
and Mathematics A. V. Tyutyunnik (Institute of Solidꢀ
State Chemistry, Ural Division, Russian Academy of
Sciences) for investigations of polycrystalline salts
and II
This work was supported by the Interdisciplinary
Integration Project no. 112 of the Siberian Division,
I
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7
RUSSIAN JOURNAL OF INORGANIC CHEMISTRY Vol. 55 No. 9 2010