Pr10[Si10-xAlxO9+xN 17-x]Cl with x ≈ 1 - An oxonitridoaluminosilicate chloride

Article abstract of DOI:10.1002/zaac.200500368

The oxonitridoaluminosilicate chloride Pr₁₀[Si _10-xAl_xO_9+xN_17-x]Cl was obtained by the reaction of praseodymium metal, the respective chloride, AlN and Al(OH) ₃ with Si(NH)₂ in a radiofrequency furnace at temperatures around 1900°C. The crystal structure was determined by single-crystal X-ray diffraction (Pbam, no. 55, Z = 2,a = 10.5973(8) A, b = 11.1687(6) A, c = 11.6179(7) A, R1 = 0.0337). The sialon crystallizes isotypically to the oxonitridosilicate halides Ce ₁₀[Si₁₀O₉N₁₇]Br, Nd ₁₀[Si₁₀O₉N₁₇]Br and Nd ₁₀[Si₁₀O₉N₁₇]Cl, which represent a new layered structure type. The structure refinement was performed utilizing an O/N-distribution model according to Paulings rules, i.e. nitrogen was positioned on all bridging sites and mixed O/N-occupation was assumed on the terminal sites resulting in charge neutrality of the compounds. The Si and Al atoms were refined equally distributed on their three crystallographic sites, due to their poor distinguishability by X-ray analysis. The tetrahedra layers of the structure consist of condensed [(Si,Ai)N₂(O,N)₂] and [(Si,Al)N₃(O,N)] tetrahedra of Q² and Q³ type. The chemical composition of the compound was derived from electron probe micro analyses (EPMA).

Full text of DOI:10.1002/zaac.200500368

DOI: 10.1002/zaac.200500368
Pr [Si
Al O N17؊x]Cl with x ഠ 1 ؊ an Oxonitridoaluminosilicate
1
0
10؊x
x
9؉x
Chloride
Alexandra Lieb, Rainer Lauterbach, and Wolfgang Schnick*
München, Department Chemie und Biochemie der Ludwig-Maximilians-Universität
Received September 9th, 2005.
Abstract:
Pr10[Si10ϪxAl O N
x 9ϩx
dymium metal, the respective chloride, AlN and Al(OH)
The
oxonitridoaluminosilicate
17Ϫx]Cl was obtained by the reaction of praseo-
with
2
Si(NH) “ in a radiofrequency furnace at temperatures around
chloride
occupation was assumed on the terminal sites resulting in charge
neutrality of the compounds. The Si and Al atoms were refined
equally distributed on their three crystallographic sites, due to their
poor distinguishability by X-ray analysis. The tetrahedra layers of
3
“
1
900°C. The crystal structure was determined by single-crystal
the structure consist of condensed [(Si,Al)N
N (O,N)] tetrahedra of Q and Q type. The chemical composition
3
2
(O,N)
2
] and [(Si,Al)-
˚
2
3
X-ray diffraction (Pbam, no. 55, Z ϭ 2,a ϭ 10.5973(8) A, b ϭ
˚
˚
1
1.1687(6) A, c ϭ 11.6179(7) A, R1 ϭ 0.0337). The sialon crystalli-
zes isotypically to the oxonitridosilicate halides Ce10[Si10 17]Br,
Nd10[Si10 17]Br and Nd10[Si10 17]Cl, which represent a new
of the compound was derived from electron probe micro analyses
(EPMA).
9
O N
O
9
N
9
O N
layered structure type. The structure refinement was performed
utilizing an O/N-distribution model according to Paulings rules, i.e.
nitrogen was positioned on all bridging sites and mixed O/N-
Keywords: Praseodymium; Chloride; Oxonitridoaluminosilicate;
Sialon; Crystal structure; Electron probe micro analysis (EPMA)
1
Introduction
materials with high stability and efficiency [14, 15]. The im-
plantation of aluminum and oxygen in the nitridosilicate
networks and the occurrence of additional anions in the
coordination sphere of the metals can be used to tune the
optical properties of the doping metal by changes in its
ligand field. This strategy is supported by the existence of
significant phase widths in these compounds.
In this paper we present a sialon compound that is iso-
typic to an oxonitridosilicate, showing the possibility of
aluminum incorporation in these systems. In addition it
represents the first chlorine containing oxonitridoalumino-
silicate (sialon).
With respect to their composition oxonitridosilicates re-
present an intermediate class of compounds between oxo-
silicates and nitridosilicates. Further partial substitution of
silicon with aluminum leads to the oxonitridoalumino-
silicates (so-called sialons). For application such sialons are
often synthesized by hot press techniques and the first
members of this class of compounds were made from the
reaction of Si N and Al O [1Ϫ3]. The crystallographic
structures of these sialons derive mainly from those of
α- and β-Si N . In the meantime several sialons with
anionic networks and additional cations have been synthe-
sized and characterized. Some of these sialons are isotypic
to known nitrido- and oxonitridosilicate structures, like
SrEr[SiAl O N ] [4] (isotypic to MYb[Si N ] with M ϭ Sr,
3
4
2
3
3
4
2
Synthesis
3
3
4
4
7
2.1 Synthesis of AlN
Ba [5, 6]), Nd [Si AlON ] [7] (isotypic to Ln Si N with
3
5
10
3
6
11
Ln ϭ La, Ce, Pr, Nd, Sm [8Ϫ10]), Y Si Al O3ϩxN
2
3Ϫx
x
4Ϫx
Single-phase and crystalline AlN was obtained by the reaction
of Al (purity > 99.9 %, Fluka) with a continuous stream of pure
nitrogen. Five reaction cycles of 2 h each at 900°C (heating rate
1°C / min, cooling rate 20°C / min) with subsequent grinding of
the sintered product were performed. The purity of the product
was checked by X-ray powder diffraction [16], and the absence of
NϪH groups was determined by IR-spectroscopic investigations.
The AlN deriving from this procedure is considered to be more
reactive than the commercially available crystalline compound.
[
11]
(isotypic
to
melilite
Y Si O N )
or
2
4
3
4
Sr Al Si12ϪxN16ϪxO2ϩx with x ഠ 2 [12] (isotypic to
2
x
BaSi N O [13]).
6
8
Such compounds are considered to be very interesting for
doping with suitable rare earth metals to create luminescent
*
Prof. Dr. W. Schnick
Department Chemie und Biochemie
Lehrstuhl für Anorganische Festkörperchemie
Ludwig-Maximilians-Universität München
Butenandtstraße 5Ϫ13 (D)
2.2 Synthesis of Al O
2 3
Al
made by alkaline precipitation of dissolved aluminum with NH
Therefore pure Al (2.4 g / 9 mmol, Fluka, purity > 99 %) was
dissolved and refluxed for 60 min in pure, concentrated HCl. NH
2 3
O was used as an oxygen source for the sialon syntheses and
.
D-81377 München, Germany
Fax: ϩ49-(0)89-2180-77440
E-Mail: wolfgang.schnick@uni-muenchen.de
3
3
Z. Anorg. Allg. Chem. 2006, 632, 313Ϫ318
© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
313

A. Lieb, R. Lauterbach, W. Schnick
Table 1 Crystallographic data and details of the single crystal
Table 2 Atomic coordinates and isotropic displacement para-
˚
2
X-ray data collection for Pr10[Si10ϪxAl
x
O
9ϩx
N17Ϫx]Cl.
meters (A ) for Pr10[Si10ϪxAl O N17Ϫx]Cl determined by single-
x 9ϩx
crystal X-ray diffraction with standard deviations in parentheses.
Diffractometer, monochromator
Radiation
STOE IPDS, graphite
MoKα (λ ϭ 0.71073 A)
Ueq is defined as one third of the trace of the U tensor.
ij
˚
Temperature / K
Space group, crystal system
293(2)
Atom
Wyck
x
y
z
s.o.f.
U
eq
Pbam, orthorhombic
10.5973(8)
11.1687(6)
11.6179(7)
1375.07(15)
Z ϭ 2
0.300 x 0.167 x 0.148
light green
5.092
6.39 < 2θ < 63.04
15467
2384
2222
122
˚
Lattice parameters, a / A
Pr1
Pr2
Pr3
Pr4
(Si,Al)1 8i
(Si,Al)2 8i
8i
0.64361(3)
0.87184(4)
1
0.61397(4) Ϫ0.12821(4)
0.88540(13) 0.25798(13)
0.65176(13) 0.35658(13)
0.78249(19) 0.11073(17)
0.8337(4)
1.0259(4)
0.7716(4)
0.6015(6)
0.6815(4)
0.9186(4)
0.10332(3)
0.12186(4)
0
0.23600(3)
1
1
1
1
0.01299(9)
0.01570(11)
0.01195(10)
0.01487(10)
0.0102(3)
0.0101(2)
0.0105(3)
0.0127(8)
0.0161(8)
0.0128(7)
0.0140(11)
0.0144(7)
0.0121(7)
0.0148(10)
0.0195(11)
˚
b / A
1
4h
4e
4g
/
2
˚
c / A
0.16798(3)
0
0.24679(11) 0.9, 0.1
0.36513(12) 0.9, 0.1
˚
3
Cell volume, V / A
Formula units
Crystal size / mm3
(
Si,Al)3 4g
0.0000
0.9, 0.1
1
1
1
Crystal color
N1
N2
N3
N4
(N,O)5
(N,O)6
8i
8i
8i
4h
8i
0.1835(4)
0.1941(4)
0.2529(4)
0.3917(6)
0.4921(4)
0.3984(3)
Ϫ0.1231(4)
0.2862(4)
0.3527(4)
Ϫ3
Calculated density / g cm
Diffraction range / °
Measured reflections
Independent reflections
Observed reflections
Refined Parameters
1
/2
1
0.3097(3)
0.2040(3)
0
0.17, 0.83
0.17, 0.83
0.17, 0.83
0.17, 0.83
8i
(
(
N,O)7
N,O)8
4g
4g
4h
0.8506(5) Ϫ0.0268(5)
0.6199(6)
0.5755(5)
0.0894(6)
0.0491(5)
0
R
int
0.0768
1876
1
Cl1
/
2
0.480(12)* 0.0304(15)
F(000)
Extinction coefficient, c
Absorption correction
Absorption coefficient / mm
Min. / max. transmission
Min. / max. residual electron density / e / A
GooF
0.00169(11)
semi-empirical, multi-scan
17.939
0.027 / 0.070
Ϫ2.574 / 2.818
1.206
*
This value equals 0.5, within the uncertainties of the refinement.
Ϫ1
˚
2
Table
3
Anisotropic displacement parameters (A ) for
17Ϫx]Cl determined by single-crystal X-ray dif-
fraction with standard deviations in parentheses. The anisotropic
˚
3
x 9ϩx
Pr10[Si10ϪxAl O N
R
wR
1
(all data) [I 2σ(I)]
(all data) [I 2σ(I)]
0.0337 [0.0305]
0.0775 [0.0763]
2
2
2
displacement factor exponent is of the form -2p [(ha*) U11
ϩ···2hka*b*U12].
subsequently was mixed to the solution until Al(OH)
3
, as a white
Atom
U
11
U
22
U
33
U
23
U
13
U
12
voluminous precipitate was formed. It was separated from the solu-
tion and washed with destilled water. The product was dried at
Pr1
Pr2
Pr3
Pr4
0.01035(13) 0.01114(15) 0.01749(15) Ϫ0.00146(9) Ϫ0.00038(9) Ϫ0.00002(8)
0.0191(2)
0.01289(17) 0.01283(19) 0.01013(17)
0.0248(2) 0.01098(19) 0.00888(17)
0.0159(2)
0.01216(19)
0
0
0
0
0
0
0.00562(14)
0.00105(13)
0.00217(14)
Ϫ0.0002(5)
0.0001(4)
1
50°C under vacuum for 48 h. IR-spectroscopic investigations and
X-ray powder diffraction substantiated the purity of the derived
Al [17].
(Si,Al)1 0.0100(5)
0.0113(6)
0.0103(6)
0.0109(8)
0.0092(6)
0.0093(6) Ϫ0.0004(5) Ϫ0.0002(4)
0.0086(8)
0.0003(5) Ϫ0.0002(4)
2
O
3
(Si,Al)2 0.0106(5)
(Si,Al)3 0.0121(8)
0
0
Ϫ0.0001(6)
N1
N2
N3
N4
0.0173(19) 0.0128(19) 0.0079(17) 0.0022(14)
0.0140(19) 0.016(2) 0.019(2) Ϫ0.0013(17) Ϫ0.0027(16)
0.0121(17) 0.0142(19) 0.0121(18) Ϫ0.0006(15) Ϫ0.0004(14)
0.017(3) 0.016(3) 0.010(3) 0.
0.0011(14) Ϫ0.0014(15)
0.0018(16)
0.0018(14)
0.005(2)
2
.3 Synthesis of Pr [Si
Al O9؉xN17؊x]Cl
x
1
0
10؊x
A mixture of Pr (120 mg / 0.85 mmol, Chempur, 99.9 %, powder),
Si(NH) ” (58 mg / 1 mmol) (synthesized according to ref. [18]),
PrCl (50 mg / 0.2 mmol, Chempur, 99.9 %, ultradry), Al
30 mg / 0.3 mmol) and AlN (50 mg / 1.2 mmol) was thoroughly
mixed and transferred into a tungsten crucible in a glove box
argon atmosphere). The crucible then was positioned in a water-
0
(N,O)5 0.0131(16) 0.0134(17) 0.0168(18) 0.0029(14)
0.0019(13) Ϫ0.0014(13)
0.0004(13) Ϫ0.0003(12)
(N,O)6 0.0128(16) 0.0118(17) 0.0116(16) Ϫ0.0001(13)
“
2
(N,O)7 0.018(3)
N,O)8 0.015(2)
Cl1 0.035(3)
0.015(3)
0.016(3)
0.036(3)
0.012(2)
0.028(3)
0.021(2)
0
0
0
0
0
0
0.0020(19)
Ϫ0.001(2)
0.005(2)
(
3
2 3
O
(
(
structure was solved by direct methods using SHELXTL
23] and refined with anisotropic thermal displacement para-
cooled silica glass reactor of a radiofrequency furnace. It was
heated under a pure nitrogen atmosphere to 1500°C within 1 h,
then to 1900°C within 1 h, maintained at that temperature for 1 h
and subsequently cooled to 1200°C within 60 h. Finally, the prod-
uct was quenched to room temperature. Further details about the
experimental setup are given in ref. 4.
[
meters for all atoms. Due to their poor distinguishability by
X-ray analysis, the Si and Al atoms were refined equally
distributed on their three crystallographic sites, employing
the respective amounts of Si and Al according to the
EPMA analysis. The refinement of the light atoms (O, N)
was performed, according to Paulings rules [24], assuming
N on all bridging positions and mixed O/N-occupancies of
the terminal sites, thus leading to charge neutrality of the
compounds. Relevant crystallographic data and details of
the X-ray data collection are shown in Table 1. Table 2 gives
the positional and isotropic displacement parameters for all
atoms. Table 3 lists the anisotropic displacement parameter
and Table 4 lists selected interatomic distances and angles.
Further details of the crystal structure investigation are
available from the Fachinformationszentrum Karlsruhe,
D-76344 Eggenstein-Leopoldshafen (Germany), e-mail:
crysdata@FIZ-karlsruhe.de, on quoting the depository
The reaction yielded a light green crystalline product, together with
small amounts of Pr
Pr Si [21, 22] as crystalline by-products. In addition,
amorphous by-products could be found, but not identified.
2 3.5 3 6
Si2.5Al0.5O N3.5 [19], Pr Si N11 [20] and
4
2 7 2
O N
3
Single-crystal X-ray analysis
X-ray diffraction data of Pr [Si
collected using an IPDS-I diffractometer (STOE, Darm-
stadt) using Mo-K radiation. According to the observed
reflection conditions (0kl with k ϭ 2n, h0l with h ϭ 2n, h00
with h ϭ 2n and 0k0 with k ϭ 2n) of the orthorhombic
lattice, the space group Pbam (no. 55) was determined. The
Al O9ϩxN17Ϫx]Cl was
10Ϫx x
1
0
α
314
zaac.wiley-vch.de
© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Z. Anorg. Allg. Chem. 2006, 313Ϫ318

x 9ϩx
Pr10[Si10ϪxAl O N17Ϫx]Cl with x ഠ 1
˚
Table 4 Selected interatomic distances /A and angles /° in the
structure of Pr10[Si10ϪxAl 17Ϫx]Cl determined by single-
crystal X-ray diffraction with standard deviations in parentheses.
Table 5 Parameters of the EPMA measurements.
x
9ϩx
O N
Element, Standard
X-ray line
Spectrometer Measuring time on Measuring time on
crystal
peak / sec
background / sec
Pr1Ϫ(O,N)5
Pr1Ϫ(O,N)6 (2 x)
Pr1Ϫ(O,N)6
Pr1ϪN3
Pr1ϪN1
Pr1ϪN2
2.390(4)
2.411(4)
2.413(4)
2.543(4)
2.565(4)
2.649(5)
2.7577(7)
3.2085(17)
Pr2ϪN4
Pr2ϪN3 (2 x)
Pr2ϪN4
Pr2Ϫ(O,N)5
Pr2Ϫ(O,N)5
Pr2ϪN2 (2 x)
Pr2ϪCl1
2.439(7)
2.490(4)
2.587(7)
2.704(4)
2.704(4)
3.08(5)
Pr, Lα
Si, Kα
Al, Kα
N, Kα
O, Kα
Cl, Kα
Pr
Ce
Al
Ce
Albite [35]
3
Si
6
N
11 [20] PET
11 [34] TAP
60
90
60
120
40
180
30ϩ30
90
60
60ϩ60
40
90ϩ90
3
Si
6
N
2
O
3
Si
3
[35]
TAP
6
N
11
LDE1
LDE1
Scapolite [36] PETH
Pr1Ϫ(O,N)8
Pr1ϪCl1
3.244(6)
Pr3Ϫ(O,N)7 (2 x)
Pr3Ϫ(O,N)5 (2 x)
Pr3ϪN2 (2 x)
2.531(4)
2.534(4)
2.581(5)
2.753(5)
Pr4Ϫ(O,N)6 (2 x)
Pr4Ϫ(O,N)8
Pr4Ϫ(O,N)8
Pr4ϪN1 (2 x)
Pr4Ϫ(O,N)7
2.413(4)
2.431(6)
2.516(6)
2.603(4)
2.751(6)
centrations in the analyzed oxonitridoaluminosilicate.
Praseodymium produces a large number of emission lines
which may overlap with the N, O or Cl Kα lines. Further
details of the measurements can be taken from ref. [28]. The
used standards are listed in Table 5.
Pr3ϪN1 (2 x)
(Si,Al)1Ϫ(O,N)6
(Si,Al)1ϪN2
(Si,Al)1ϪN3
(Si,Al)1ϪN1
1.682(4)
1.713(5)
1.724(4)
1.748(4)
(Si,Al)2Ϫ(O,N)5
(Si,Al)2ϪN4
(Si,Al)2ϪN2
1.674(4)
1.701(3)
1.715(5)
1.725(5)
(Si,Al)2Ϫ(O,N)5
(
(
(
(
Si,Al)3Ϫ(O,N)7
Si,Al)3ϪN1
Si,Al)3ϪN1
Si,Al)3Ϫ(O,N)8
1.698(6)
1.732(4)
1.732(4)
1.739(6)
Cl1ϪCl1*
1.940(11)
5
Results and Discussion
5.1 EPMA
(
(
O,N)6Ϫ(Si,Al)1ϪN2
O,N)6Ϫ(Si,Al)1ϪN3
106.6(2)
112.8(2)
113.8(2)
105.4(2)
107.1(2)
110.6(2)
(O,N)5Ϫ(Si,Al)2ϪN4 101.9(3)
(O,N)5Ϫ(Si,Al)2ϪN2 103.8(2)
Using
EPMA,
a
single
crystal
of
Pr [Si
Al O9ϩxN17Ϫx]Cl, was investigated (19 spots).
x
10
10Ϫx
N2Ϫ(Si,Al)1ϪN3
O,N)6ϪSi1ϪN1
N4Ϫ(Si,Al)2ϪN2
109.0(3)
(
(O,N)5Ϫ(Si,Al)2ϪN3 115.8(2)
The averaged results are given in Table 6. The low values of
sigma indicate high homogeneity of the crystal. The total
N2Ϫ(Si,Al)1ϪN1
N3Ϫ(Si,Al)1ϪN1
N4Ϫ(Si,Al)2ϪN3
N3Ϫ(Si,Al)2ϪN3
117.5(3)
107.9(2)
1
of the analyses is 102.1 %, thus indicating a good quality
of the analyses of light elements in a difficult matrix. Due to
measurement uncertainty the atomic composition of such a
system can not be obtained exactly. Given that there are no
defects in the SiϪAlϪOϪN substructure a formula
(
O,N)7Ϫ(Si,Al)3ϪN1 (2x) 106.95(19)
N1Ϫ(Si,Al)3ϪN1 111.3(3)
O,N)7Ϫ(Si,Al)3Ϫ(O,N)8 107.3(3)
O,N)8Ϫ(Si,Al)3ϪN1 (2x) 111.98(19)
(Si,Al)3ϪN1Ϫ(Si,Al)1 179.6(3)
(Si,Al)1ϪN2Ϫ(Si,Al)2 163.0(3)
(Si,Al)1ϪN3Ϫ(Si,Al)2 123.5(3)
(Si,Al)2ϪN4Ϫ(Si,Al)2 134.3(4)
(
(
*
Distance between symmetrically equivalent split positions.
29Ϫ
[Si10ϪxAl O9ϩxN17Ϫx
]
with 0.99 Յ x Յ 1.17, conforming
x
to charge neutrality, can be derived. The value for N, which
is known to be slightly too high for reasons of measurement
artifacts, has not been taken into account for the calcu-
lation. The resulting averaged elemental composition
Pr [Si AlO N ]Cl (x ϭ 1) was implemented in the single-
number CSD-391345, the name of the author(s) and ci-
tation of the paper.
4
EPMA-analysis
10
9
10 16
crystal X-ray refinement.
Quantitative chemical analyses on the microscale by elec-
tron probe micro analysis (EPMA) were carried out with a
Jeol JXA-8900 R superprobe using an accelerating voltage
of 15 kV, a beam current of 80 nA and a 3 μm measuring
Table
Pr10[Si10ϪxAl O N
x 9ϩx
6
Quantitative results of the EPMA analyses of
17Ϫx]Cl with x ഠ 1 (19 measuring spots).
Pr
Si
Al
O
N
Cl
Total
spot. The total volume analyzed was approximately
3
1
0Ϫ15 μm . The microprobe is equipped with synthetic
Wt-%
At-%
average 68.06 11.98 1.43 7.73
sigma 0.09 0.03 0.02 0.05
11.2
0.10
1.73 102.1
0.01 0.18
1
multilayer spectrometer crystals with large d-spacing for
quantitative wavelength dispersive analysis of light ele-
ments. For N and O analysis, the LDE1 crystal with 2d ϭ
average 21.07 18.60 2.30 21.1
34.8
0.20
2.12
0.01
1
sigma 0.08
0.09
0.02 0.11
stoichiom.
formula
10
8.83
1.09 10.01 16.53 1.01
600 nm was used. Matrix correction was carried out with
the CITZAF program [25]. For the analysis, the samples
were mounted with epoxy resin into cylindrical holes in an
epoxy pellet of 25 mm diameter and polished with a final
diamond powder grain size of 0.25 μm. In addition, the
samples have been coated with carbon. Since the quantita-
tive analysis of light elements such as N and O, and also of
Cl are not a routine EPMA technique (see [26, 27]), signifi-
cant care was taken to minimize errors that may occur dur-
ing measurements of these low-energy X-ray emission lines.
In addition, the analysis of light elements becomes more
difficult in the presence of lanthanide elements in high con-
5
.2 Crystal structure
The title compound Pr [Si
typic sialon to Ln [Si O N ]X with Ln ϭ Ce, Nd and
X ϭ Cl, Br [29], which represent a new layered structure
type. The cell parameters of the praseodymium sialon are
10.5973(8) A, b ϭ 11.1687(6) A, c ϭ 11.6179(7) A. They
show an intermediate dimension compared to the cerium
Al O9ϩxN17Ϫx]Cl is an iso-
1
0
10Ϫx
x
10
10
9
17
˚
˚
˚
Z. Anorg. Allg. Chem. 2006, 313Ϫ318
© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
zaac.wiley-vch.de
315

A. Lieb, R. Lauterbach, W. Schnick
Fig.
Pr10[Si10ϪxAl
1
Anionic
layer
[Si10ϪxAl
x
O
9ϩx
3
N
17Ϫx]29Ϫ
of
x
O
9ϩx
N
17Ϫx]Cl. Tetrahedra of Q type: gray, tetra-
2
hedra of Q type: black, N: medium gray spheres, mixed O/N: white
spheres. View along [010].
Fig. 3 Coordination spheres of the four crystallographically diffe-
rent Pr atoms. Displacement ellipsoids are drawn at the 90 % pro-
bability level.
Fig. 4 Possible positions and assumed coordination of the chlo-
ride anions in Pr10[Si10ϪxAl O N17Ϫx]Cl (split position with an
x 9ϩx
occupancy factor of 0.5). Pr: large gray spheres, chloride: small
black spheres, N: small medium gray spheres, mixed O/N: small
white spheres. View along [001].
Fig. 2 Formfitting six membered rings of Pr1 and Pr2 atoms and
their position between the oxonitridoaluminosilicate layers. Pr3 and
Pr4 are omitted. Pr1: black spheres, Pr2: gray spheres. View along
[
001].
layers (Fig. 2). These cations are coordinated by O, N and
the chloride ions (Fig. 3). The chloride ions are statistically
disordered on two neighboring and symmetrically equi-
valent positions in the center of the Pr1/Pr2-rings. The
and the neodymium oxonitridosilicates (Ce [Si O N ]Br:
a ϭ 10.6117(9) A, b ϭ 11.2319(10) A, c ϭ 11.6288(8) A;
Nd [Si O N ]Br: a ϭ 10.523(2) A, b ϭ 11.101(2) A, c ϭ
1
1
0
10
9
17
˚
˚
˚
˚
distance between the two positions is 1.940(11) A and can
˚
˚
˚
be compared to the ClϪCl distance (1.931(8) A) in
1
0
10
9
˚
17
3ϩ
1.546(2) A), owing to the medium sized Pr ions, com-
Nd [Si O N ]Cl. Due to the split position (occupancy
10
10
9
17
3
ϩ
3ϩ
pared to the smaller Nd and the larger Ce ions.
factor ϭ 0.5) only one of the chloride ions is present at
a time. The chloride ion has three shorter and five longer
distances to the surrounding praseodymium cations and it
is therefore assumed to be predominantly coordinated by
three lanthanide atoms forming a decentered trigonal co-
ordination sphere (Fig. 4). Since several anions (O, N) are
located between the three closer and the five more distant
praseodymium cations, the threefold coordination of the
halide atoms is more likely than an enlarged cationic coor-
dination sphere. A similar threefold coordination of halide
atoms has already been found in lanthanide oxosilicate
2
9Ϫ
The anionic layers [Si10ϪxAl O9ϩxN17Ϫx
]
(Fig. 1) are
x
made up of [(Si,Al)N (O/N) ] and [(Si,Al)N (O/N)] units
representing Q and Q type tetrahedra. According to
Liebau the [Si10ϪxAl O9ϩxN17Ϫx
pound has to be specified as an open-branched vierer single
2
2
3
2
3
2
9Ϫ
]
layer of the title com-
x
chain layer [30Ϫ32]. A more detailed description of the topo-
3
ϩ
logy can be found in ref. 29. The Pr ions are located on
four different crystallographic sites. Pr1 and Pr2 form six-
membered rings in chair conformation situated formfitting
between the six-membered tetrahedra rings of the silicate
316
zaac.wiley-vch.de
© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Z. Anorg. Allg. Chem. 2006, 313Ϫ318

x 9ϩx
Pr10[Si10ϪxAl O N17Ϫx]Cl with x ഠ 1
Festkörpern”, projekt SCHN 377/9) and the Fonds der Chemischen
Industrie for generous financial support. Thanks are given to Dr.
Heidi E. Höfer (Department of Mineralogy, Institut for Petrology
and Geochemistry, J.-W. Goethe University of Frankfurt/Main,
Germany) for performing the EPMA measurements. Additional
thanks are given to Dr. Oliver Oeckler (Department of Chemistry
and Biochemistry, LMU Munich, Germany) for helpful crystallo-
graphic advice.
Table 7 Environment of the halide anion represented by selected
˚
interatomic
distances structure
/A
in
the
of
Pr10[Si10ϪxAl
x
O
9ϩx
N
17Ϫx]Cl and Nd10[Si10O N17]Cl determined by
9
single-crystal X-ray diffraction with standard deviations in paren-
theses.
Pr10[Si10ϪxAl
x
O
9ϩx
N17Ϫx]Cl
9
Nd10[Si10O N17]Cl
Pr1
Pr2
Pr1
Pr2
Pr2
Pr2
3.2085(2)
3.244(6)
4.207(4)
4.262(6)
4.804(6)
5.111(5)
2x
2x
Nd1
Nd2
Nd1
Nd2
Nd2
Nd2
3.208(1)
3.207(4)
4.196(3)
4.263(4)
4.805(3)
5.062(4)
2x
2x
References
(
N3
N4
(
N2
(
(
O,N)5
3.453(6)
3.525(7)
3.836(9)
3.829(4)
3.830(6)
3.860(5)
3.865(4)
2x
2x
(O,N)5
N3
N4
(O,N)6
N2
(Si,Al)2
(O,N)6
3.426(4)
3.504(5)
3.792(6)
3.799(3)
3.821(4)
3.837(3)
3.838(3)
2x
2x
[
1] Y. Oyama, O. Kamigaito, Jpn. J. Appl. Phys. 1971, 10, 1637.
[2] K. H. Jack, W. I. Wilson, Nature 1972, 238, 28.
[3] K. H. Jack, J. Mater. Sci. 1976, 11, 1135.
O,N)6
2x
2x
2x
2x
2x
2x
2x
2x
[
[
[
4] W. Schnick, H. Huppertz, R. Lauterbach, J. Mater. Chem.
Si,Al)2
O,N)6
1999, 9, 289.
5] H. Huppertz, W. Schnick, Angew. Chem. 1996, 108, 2115; An-
gew. Chem. Int. Ed. 1996, 35, 1983.
6] H. Huppertz, W. Schnick, Z. Allg. Anorg. Chem 1997, 623,
2
12.
[7] R. Lauterbach, W. Schnick, Z. Anorg. Allg. Chem. 2000, 626,
6.
[8] M. Woike, W. Jeitschko, Inorg. Chem. 1995, 34, 5105.
[9] T. Schlieper, W. Schnick, Z. Anorg. Allg. Chem. 1995, 621,
1535.
10] T. Schlieper, W. Schnick, Z. Kristallogr. 1996, 211,254.
11] J. W. H. van Krevel, H. T. Hintzen, R. Metselaar, Mater. Res.
Bull. 2000, 35, 747.
12] Z. Shen, J. Grins, S. Esmaeilzadeh, H. Ehrenberg, J. Mater.
Chem. 1999, 9, 1019.
chlorides, e.g. Tb Cl [SiO ] [33]. The interatomic distances
3
5
4
between the chloride atoms and their surrounding atoms
are listed and compared to the data from
Nd [Si O N ]Cl in Table 7, thus showing the similarity
5
1
0
10
9
17
of the chlorine coordination sphere in these compounds.
Pr3 and Pr4 do not participate in the coordination of the
halide ions and are situated closer to the [(Si,Al)N (O/N) ]
[
[
2
2
2
Q type tetrahedra. Pr3 and Pr4 are solely coordinated by
O and N (Fig. 3).
[
[13] F. Stadler, R. Kraut, O. Oeckler, S. Schmid, W. Schnick, Z.
Anorg. Allg. Chem. 2005, 631, 1773.
6
Conclusions
[14] R. Müller-Mach, G. Müller, M. R. Krames, H. A. Höppe, F.
Stadler, W. Schnick, T. Jüstel, P. Schmidt, Phys. Stat. Sol. (A)
2005, 202, 1727.
The new compound Pr [Si
Al O9ϩxN17Ϫx]Cl shows,
10Ϫx x
1
0
that in addition to the class of oxonitridosilicate halides the
class of oxonitridoaluminosilicate chlorides (sialon chlo-
rides) is accessible. This demonstrates the large range of
substitution possibilities in the field of silicate chemistry.
Substitution can be achieved on the cation positions and
the tetrahedra centers (Si,Al) and concerning the ligand
atoms (O,N) and additional anions, such as oxygen or hal-
ides. Furthermore, it could be shown that the unpre-
cedented silicate layer of Ln [Si O N ]X (Ln ϭ Ce, Nd
and X ϭ Cl, Br) also exists in the sialon system. Hence it
is stressed, that the existence of the new layer topology does
not depend on the tetrahedra center, but derives mainly
from the incorporation of nitrogen and/or the halide. The
implantation of bromine, as it is possible concerning the
oxonitridosilicates, will be subject of further investigations.
The characterization of the new oxonitridoaluminosili-
cate chloride was carried out by means of single-crystal
X-ray and electron probe micro analyses. The formerly es-
tablished method for measuring light elements by EPMA
[
15] H. A. Höppe, H. Lutz, P. Morys, W. Schnick, A. Seilmeier, J.
Phys. Chem. Solids 2000, 61, 2001.
[16] G. A. Geffrey, G. S. Parry, R. L. Mozzi, J. Chem. Phys. 1956,
25, 1024.
[
[
17] E. J. W. Verwey, Z. Kristallogr. 1935, 91, 317.
18] H. Lange, G. Wötting, G. Winter, Angew. Chem. 1991, 103,
1
606; Angew. Chem. Int. Ed. 1991, 30, 1579.
19] R. Lauterbach, W. Schnick, Z. Anorg. Allg. Chem. 1999, 625,
29.
[
4
1
0
10
9
17
[
[
20] T. Schlieper, W. Schnick, Z. Kristallogr. 1996, 211, 254.
21] R. Marchand, A. Jayaweera, P. Verdier, J. Lang, C. R. S e´ ances
Acad. Sci. C 1976, 283, 675.
[22] J. P. Guha, J. Mater. Sci. 1980, 15, 262.
[23] G. M. Sheldrick, SHELXS97 Program for the Solution of
Crystal Structures and SHELXL97 Program for the Refine-
ment of Crystal Structures, Univ. Göttingen 1997.
[
[
24] P. E. D. Morgan, J. Mater. Sci. 1986, 21, 4305.
25] J. T. Armstrong, Caltech 1993, Jeol License of CITZAF Ver-
sion 3.5.
[
[
26] G. F. Bastin, H. J. M. Heijligers, Quantitative Electron Probe
Microanalysis of Nitrogen, Internal Report, Eindhoven Uni-
versity of Technology, 1988.
27] G. F. Bastin, H. J. M. Heijligers, Quantitative Electron Probe
Microanalysis of Oxygen, Internal Report, Eindhoven Univer-
sity of Technology, 1989.
[
28] could be successfully transferred to the sialon system.
Acknowledgements. The authors would like to thank the Deutsche
Forschungsgemeinschaft (SPP 1136 “Substitutionseffekte in
Z. Anorg. Allg. Chem. 2006, 313Ϫ318
© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
zaac.wiley-vch.de
317

A. Lieb, R. Lauterbach, W. Schnick
[
28] A. Lieb, M. T. Weller, P. F. Henry, R. Niewa, R. Pöttgen, R.-
[32] K. Goetzke, H.-J. Klein, J. Non-Cryst. Solids 1991, 127, 215.
[33] M. Petter, I. Hartenbach, T. Nikelski, Th. Schleid, Z. Kristal-
logr. 2004, 219, 177.
D. Hoffmann, H.E. Höfer, W. Schnick, J. Solid State Chem.
2005, 178, 976.
[
[
29] A. Lieb, W. Schnick, J. Solid State Chem. 2005, 178, in press.
30] F. Liebau, Structural Chemistry of Silicates, Springer, Berlin
[34] T. Schlieper, W. Schnick, Z. Anorg. Allg. Chem. 1995, 621,
1535.
1
985.
[35] A.V. McGuire, C.A. Francis, M. Darby Dyar, Am. Miner.
1992, 77, 1087.
[36] E. Jarosewich, J.A. Nelen, J.A. Norberg, Geostandards News-
letter 1980, 4, 43.
[
31] The classification can also be determined by using the pro-
gramm CRYSTANA via http://www.is.informatik.uni-kiel.de/
hjk/crystana.html which is partially based on ref. 30
318
zaac.wiley-vch.de
© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Z. Anorg. Allg. Chem. 2006, 313Ϫ318