Syntheses, structures, and spectroscopic properties of K 9Nd[PS4]4, K3Nd[PS4] 2 Cs3Nd[PS4]2, and K 3Nd3[PS4]4

Article abstract of DOI:10.1021/ic800143x

Four new quaternary alkali neodymium thiophosphates K₉Nd[PS ₄]₄ (1), K₃Nd[PS₄]₂ (2), Cs₃Nd[PS₄]₂ (3), and K₃Nd ₃[PS₄]₄ (4) were synthesized by reacting Nd with in situ formed fluxes of K₂S₃ or Cs₂S ₃, P₂S₅ and S in appropriate molar ratios at 973 K. Their crystal structures are determined by single crystal X-ray diffraction. Crystal data: 1: space group C₂/c, a = 20.1894(16), b = 9.7679(5), c = 17.4930(15) A, β = 115.66(1)°, and Z = 4; 2: space group P2₁/c, a = 9.1799(7), b = 16.8797(12), c = 9.4828(7) A, β = 90.20(1)°, and Z = 4; 3: space group P2₁/n a = 15.3641(13), b = 6.8865(4), c = 15.3902(13) A, β = 99.19(1)°, and Z = 4; 4: space group C2/c, a = 16.1496(14), b = 11.6357(7), c = 14.6784(11) A, β = 90.40(1)°, and Z = 4. The structure of 1 is composed of one-dimensional ¹_∞{Nd[PS₄] ₄}^9- chains and charge balancing K⁺ ions. Within the chains, eight-coordinated Nd³⁺ ions, which are mixed with K⁺ ions, are connected by [PS₄]^3- tetrahedra. The crystal structures of 2 and 3 are characterized by anionic chains ¹_∞{Nd[PS₄]₂}^3- being separated by K⁺ or Cs⁺ ions. Along each chain the Nd³⁺ ions are bridged by [PS₄]^3- anions. The difference between the structures of 2 and 3 is that in 2 the Nd³⁺ ions are coordinated by four edge-sharing [PS₄]^3- tetrahedra while in 3 each Nd³⁺ ion is surrounded by one corner-sharing, one face-sharing, and two edge-sharing [PS₄] ^3- tetrahedra. The structure of 4 is a three-dimensional network with K⁺ cations residing in tunnels running along [110] and [110]. The {Nd(1)S₈} polyhedra share common edges with four [PS₄] tetrahedra forming one-dimensional chains ¹ _∞{Nd[PS₄]₂}^3- running along [110] and [110]. The chains are linked by {Nd(2)S₈} polyhedra yielding the final three-dimensional network ³ _∞[Nd[PS₄]₂}^3-. The internal vibrations of both crystallographically independent [PS₄] ^3- anions of 2-4 have been assigned in the range 200-650 cm ^-1 by comparison of their corresponding far/mid infrared and Raman spectra (λ_exc = 488 nm) on account of locally imposed C ₁ symmetry. In the Fourier-transform-Raman spectrum (λ_exc = 1064 nm) of 2-4, very similar well-resolved electronic Raman (ER) transitions from the electronic Nd³⁺ ground-state to two levels of the ⁴I_9/2 ground manifold and to the six levels of the ⁴I_11/2 manifold have been determined. Resonant Raman excitation via a B-term mechanism involving the ⁴I _15/2 and ⁴F_3/2 intermediate states may account for the significant intensity enhancement of the ER transitions with respect to the symmetric P-S stretching vibration ν₁. Broad absorptions in the UV/vis/NIR diffuse reflectance spectrum at 293 K in the range 5000-25000 cm^-1 of 2-4 are attributed to spin-allowed excited quartet states [⁴(I < F < S < G < D)] and spin-forbidden doublet states [²(H < G < K < D < P)] of Nd³⁺. A luminescense spectrum of 3 obtained at 15 K by excitation with 454.5 nm shows multiplets of narrow lines that reproduce the Nd³⁺ absorptions. Sharp and intense luminescence lines are produced instead by excitation with 514.5 nm. Lines at 18681 (⁴G_7/2), 16692 (⁴G_5/2), 14489 (⁴F_9/2), and 13186 cm^-1 (⁴F _7/2) coincide with the corresponding absorptions. Hypersensitive ⁴G_5/2 is split by 42 cm^-1. The most intense multiplet at about 16500 cm^-1 is assigned to the transition from ⁴G_5/2 to the Stark levels of the ground manifold ⁴I_9/2.

Full text of DOI:10.1021/ic800143x

Inorg. Chem. 2008, 47, 7523-7534
Syntheses, Structures, and Spectroscopic Properties of K Nd[PS ] ,
9 4 4
K Nd[PS ] , Cs Nd[PS ] , and K Nd [PS ]
4 4
3
4 2
3
4 2
3
3
Yuandong Wu and Wolfgang Bensch*
Institut f u¨ r Anorganische Chemie, UniVersit a¨ t Kiel, Olshausenstr. 40, D24098 Germany
Received January 24, 2008
Four new quaternary alkali neodymium thiophosphates K
4) were synthesized by reacting Nd with in situ formed fluxes of K
at 973 K. Their crystal structures are determined by single crystal X-ray diffraction. Crystal data: 1: space group C2/c, a
20.1894(16), b ) 9.7679(5), c ) 17.4930(15) Å, ꢀ ) 115.66(1)°, and Z ) 4; 2: space group P2 /c, a ) 9.1799(7),
b ) 16.8797(12), c ) 9.4828(7) Å, ꢀ ) 90.20(1)°, and Z ) 4; 3: space group P2 /n, a ) 15.3641(13), b ) 6.8865(4),
c ) 15.3902(13) Å, ꢀ ) 99.19(1)°, and Z ) 4; 4: space group C2/c, a ) 16.1496(14), b ) 11.6357(7), c ) 14.6784(11)
Nd[PS ]
9 4 4
(1), K Nd[PS ]
3 4 2
3 4 2 3 3 4 4
(2), Cs Nd[PS ] (3), and K Nd [PS ]
(
2 3
S
or Cs
2
S
3
, P and S in appropriate molar ratios
2 5
S
)
1
1
1
9-
Å, ꢀ ) 90.40(1)°, and Z ) 4. The structure of 1 is composed of one-dimensional
∞
{Nd[PS
4
]
4
}
chains and charge
+
3+
+
balancing K ions. Within the chains, eight-coordinated Nd ions, which are mixed with K ions, are connected by
]3- tetrahedra. The crystal structures of 2 and 3 are characterized by anionic chains 1
3-
[
PS
4
∞
{Nd[PS
4
]
2
}
being separated
+
+
3+
3-
by K or Cs ions. Along each chain the Nd ions are bridged by [PS
4
]
anions. The difference between the structures
3
+
3-
tetrahedra while in 3 each Nd3+ ion
]3- tetrahedra. The structure of 4 is
4
of 2 and 3 is that in 2 the Nd ions are coordinated by four edge-sharing [PS ]
4
is surrounded by one corner-sharing, one face-sharing, and two edge-sharing [PS
+
a three-dimensional network with K cations residing in tunnels running along [110] and [ 1¯ 10]. The {Nd(1)S
8
} polyhedra
3-
share common edges with four [PS
1¯ 10]. The chains are linked by {Nd(2)S
internal vibrations of both crystallographically independent [PS
4
] tetrahedra forming one-dimensional chains 1
∞
{Nd[PS
4
]
2
}
running along [110] and
3-
[
8
} polyhedra yielding the final three-dimensional network 3
∞
{Nd[PS ] } . The
4
2
]3 anions of 2-4 have been assigned in the range
00-650 cm- by comparison of their corresponding far/mid infrared and Raman spectra (λexc ) 488 nm) on account
of locally imposed C
-
4
1
2
1
symmetry. In the Fourier-transform-Raman spectrum (λexc ) 1064 nm) of 2-4, very similar well-
resolved electronic Raman (ER) transitions from the electronic Nd3 ground-state to two levels of the I9/2 ground manifold
and to the six levels of the 4I11/2 manifold have been determined. Resonant Raman excitation via a B-term mechanism
involving the 4I15/2 and 4F3/2 intermediate states may account for the significant intensity enhancement of the ER transitions
+
4
with respect to the symmetric P-S stretching vibration ν
1
. Broad absorptions in the UV/vis/NIR diffuse reflectance spectrum
at 293 K in the range 5000-25000 cm- of 2-4 are attributed to spin-allowed excited quartet states [ (I < F < S < G
1
4
2
3+
<
D)] and spin-forbidden doublet states [ (H < G < K < D < P)] of Nd . A luminescense spectrum of 3 obtained at 15
K by excitation with 454.5 nm shows multiplets of narrow lines that reproduce the Nd3 absorptions. Sharp and intense
+
luminescence lines are produced instead by excitation with 514.5 nm. Lines at 18681 ( G7/2), 16692 ( G5/2), 14489 (4F9/2),
4
4
and 13186 cm 1 (4F7/2) coincide with the corresponding absorptions. Hypersensitive G5/2 is split by 42 cm . The most
-
4
-1
intense multiplet at about 16500 cm 1 is assigned to the transition from G5/2 to the Stark levels of the ground manifold
-
4
4I9/2
.
1
. Introduction
investigation of rare earth chalcophosphates increased
significantly and a fascinating variety of new quaternary
compounds with structures ranging from separated ions
to three-dimensional networks were reported. Examples
Since the structural characterization of the first rare earth
1
thiophosphate Eu
nescent properties of the Ln[PS ] family, the explorative
4
2
[P
2
S
6
] and the discovery of the lumi-
2
3
4
5
4 2 6 4 4 2 2 6
are TlEu[PS ], KLa[P Se ], K Eu[PSe ] , KLn[P Se ]
*
To whom correspondence should be addressed. E-mail: wbensch@
ac.uni-kiel.de. Fax: +49-431-8801520.
(1) Brockner, W.; Becker, R. Z. Naturforsch. 1987, 42a, 511–512.
1
0.1021/ic800143x CCC: $40.75  2008 American Chemical Society
Inorganic Chemistry, Vol. 47, No. 17, 2008 7523
Published on Web 08/08/2008

Wu and Bensch
6
7
(
Ln ) Y, La, Ce, Pr, Gd), Rb
9
Ce[PSe
4
]
4
, A
3
Ln[P
Ce[P
La[P
(x ) 0.5),
2
Se
8
],
we are interested to recognize the effect of the radius of
the alkali cation on the structures of rare earth thiophos-
phates when applying identical reaction conditions.
In this contribution we report the syntheses and crystal
8
9
A
K
K
2
9
3
Ln[P
Ce[P
La[PQ
2
Se
7
] (A ) Rb, Cs; Ln ) Ce, Gd), K
3
2
S
8
],
],
1
0
11
4
S
16],
LiEu[PSe
La[PQ
] (Q ) S, Se), KLa[P
4
], KEu[PSe
4
],
K
2
2
Q
7
4
]
2
, K
6
4 3 4 4
] , K9-xLa1+x/3[PQ ]
1
2
structures of the new quaternary thiophosphates K
1), K Nd[PS (2), Cs Nd[PS (3), and K Nd
9
Nd[PS
4 4
]
KEu[PQ
[
[
K
K
S
4
2
3
S
6
], K
4 2 6
Eu[P S ], NaYb-
1
(
3
]
4 2
3
4
]
2
3
3
[PS (4)
4 4
]
P
P
2
S
6
],NaSm[P
Se ], Ce [P
Ce
Yb
2
S
6
],KSm[P
Se AgCe[P
[PS
2
S
7
], andNaCe[P
2
Se
6
],Cu0.4Ce1.2
-
1
4
15
17
for which one-dimensional and three-dimensional anionic
structures are observed. The results demonstrate the remark-
able diversity of rare earth containing chalcophosphate
compounds.
2
6
4
2
6
]
Rb
3
,
2
Se
6
],
K
)
, Cs
2
Nd[P
Pr, Er),
Pr [PS [P
andBa Ln
2
S
7
],
1
6
3
2
[P
3
S
12],
3
Ln
3
2i
4
]
4
(Ln
1
8
19
6
3
[PS
4
]
5
, LiEu[PS
4
], Cs
CeP
3
Pr
5
22
[PS
4
]
6
4
23
2
4
]
2
2
-
-
2
0
21
6
], Li
9
4
Gd
2
[PS
4
]
5
, Tl
2
2
S
7
, AgScP
2
S
6
,
3
2
2
4
[P S16]. Most of these compounds contain potassium and
2
. Experimental Section
were synthesized in chalcogenophosphate fluxes. In our
continuing explorative work we focused our attention on
the A-Nd-P-S system because only few Nd based
thiophosphates have been reported until now. Furthermore,
2
.1. Reagents. The following reagents were used as obtained
unless especially noted: (i) K and Cs metal, 99.0%, ABCR GmbH
Co.KG; (ii) P , 99.99%, Alfa Aesar; (iii) Nd powder, 99.99%,
00 mesh, Alfa Aesar; (iv) As powder, 99.9%, ABCR GmbH
Co.KG; (v) S powder, 99.99%, Heraeus; (vi) BaS powder,
99.99%, Alfa Aesar.
.2. Syntheses. General: K
&
2 5
S
2
2 3
S
&
(
2) (a) Komm, T.; Gudat, D.; Schleid, T. Z. Naturforsch. 2006, 61b, 766–
7
74. (b) Gauthier, G.; Jobic, S.; Boucher, F.; Macaudi e` re, P.; Huguenin,
2
2 3 2 3
S and Cs S were prepared from
D.; Rouxel, J.; Brec, R. Chem. Mater. 1998, 10, 2341–2347. (c)
Wibbelmann, C.; Brockner, W.; Eisenmann, B.; Sch a¨ fer, H. Z.
Naturforsch. 1984, 39a, 190–194. (d) Huang, Z.-L.; Cajipe, V.;
Molinie, P. J. Rare Earths 1998, 16, 167–171. (e) Huang, Z.-L.; Cajipe,
V.; Molinie, P. J. Rare Earths 1999, 16, 6–11. (f) Voloniva, A. N.;
Koubchinova, T. B.; Maximova, S. I.; Murav′ev, E. N.; Niyazov, S. A.;
Orlovskii, V. P.; Palkina, K. K.; Chibikova, N. T. Zh. Noorg. Khim.
the reaction of stoichiometric amounts of elemental K or Cs and S
powder in liquid ammonia under an argon atmosphere. For all
syntheses the starting materials were first thoroughly mixed and
loaded into fused silica ampoules in a nitrogen filled glovebox.
Afterward the ampoules were sealed under vacuum to 2 × 10-
mbar. The heating treatments were done in computer-controlled
furnaces.
3
1
987, 32, 2899–2901. (g) Palkina, K. K.; Maksimova, S. I.; Chi-
biskova, N. T.; Kuvshinova, T. B.; Volodina, A. N. Neorg. Mater.
984, 20, 1557–1560. (h) LeBret, G. C.; McCoy, H. C.; Kittelstved,
1
Preparation of K
9
Nd[PS (1). The ampoule containing the
4
]
4
K. R.; Cleary, D. A.; Twamley, B. Inorg. Chim. Acta 2003, 343, 141–
1
7
46. (i) J o¨ rgens, S.; Alili, L.; Mewis, A. Z. Naturforsch. 2005, 60b,
starting materials of K
2
S
3
, Nd, P S , S in a molar ratio of 2:1:0.5:6
2 5
05–708. (j) Palkina, K. K.; Kuvshinova, T. B.; Maksimova, S. I.;
was heated to 973 K and remained at this temperature for 5 days.
The furnace was then allowed to cool down to 373 K at a rate of
3 K/h followed by cooling to room temperature in 4 h. Crystals
were separated from excess flux by washing the reaction products
with dimethylformamide (DMF) and acetone. The product consist-
ing of transparent pale red crystals (yield: 10% based on Nd) was
dried in vacuum. An energy dispersive X-ray spectroscopy (EDX)
analysis of single crystals indicated the presence of all four elements
Chibiskova, N. T.; Tripol’skaya, T. A. Neorg. Mater. 1989, 25, 1555–
556. (k) Le Rolland, B.; McMillan, P.; Molinie, P.; Colombet, P.
1
Eur. J. Solid State Inorg. Chem. 1990, 27, 715–724.
3) Carillo-Cabrera, W.; Peters, K.; von Schnering, H. G. Z. Anorg. Allg.
Chem. 1995, 621, 557–561.
(
(
(
4) Chen, J. H.; Dorhout, P. K. Inorg. Chem. 1995, 34, 5705–5706.
5) Chondroudis, K.; McCarthy, T. J.; Kanatzidis, M. G. Inorg. Chem.
1
996, 35, 840–844.
6) Chen, J. H.; Dorhout, P. K.; Ostenson, J. E. Inorg. Chem. 1996, 35,
627–5633.
7) Chondroudis, K.; Kanatzidis, M. G. Inorg. Chem. Commun. 1998, 1,
5–57.
8) Chondroudis, K.; Kanatzidis, M. G. Inorg. Chem. 1998, 37, 3792–
797.
9) Gauthier, G.; Jobic, S.; Brec, R.; Rouxel, J. Inorg. Chem. 1998, 37,
(
(
(
(
5
(
K, Nd, P, S) in an approximately ratio of 9:1:4:16.
Preparation of K Nd[PS (2). A mixture of K
, and S powders in a molar ratio of 2:0.25:1:1:6 was heated to
5
3
4
]
2
2 3
S , BaS, Nd,
P
2 5
S
3
9
73 at 30 K/h, kept at 973 K for 5 days, cooled at 3 K/h to 373 K,
and then the furnace was turned off. The excess flux was removed
from the reaction mixture by washing with DMF, followed by
drying with acetone. The reaction product consisted of transparent
colorless platelet crystals (∼70% yield) which were stable in air
and moisture. The EDX analysis of several crystals indicated the
only presence of four elements (K, Nd, P, S) in an approximately
ratio of 3:1:2:8. In further experiments compound 2 was synthesized
2
332–2333.
(
(
(
10) Gauthier, G.; Jobic, S.; Danaire, V.; Brec, R.; Evain, M. Acta
Crystallogr. 2000, C56, e117.
11) Aitken, J. A.; Chondroudis, K.; Young, V. G., Jr.; Kanatzidis, M. G.
Inorg. Chem. 2000, 39, 1525–1533.
12) (a) Evenson, C. R., IV; Dorhout, P. K. Inorg. Chem. 2001, 40, 2884–
2
2
891. (b) Evenson, C. R., IV; Dorhout, P. K. Inorg. Chem. 2001, 40,
875–2883.
(
(
(
(
13) Goh, E.-Y.; Kim, E.-J.; Kim, S.-J. J. Solid State Chem. 2001, 160,
1
95–204.
14) Aitken, J. A.; Evain, M.; Iordanidis, L.; Kanatzidis, M. G. Inorg. Chem.
002, 41, 180–191.
15) Schleid, T.; Hartenbach, I.; Komm, T. Z. Anorg. Allg. Chem. 2002,
28, 7–9.
16) Gauthier, G.; Evain, M.; Jobic, S.; Brec, R. Solid State Sci. 2002, 4,
2 3 2 5
applying K S , Nd, P S , S in a molar ratio of 2:1:1:6. The reaction
product was treated in the same way described above and contained
2
2
in about 90% yield.
Preparation of Cs
the procedure for 2 except that Cs
3
Nd[PS
4
]
2
(3). 3 was synthesized applying
, Nd, P , As , and S were
6
2
S
3
2
S
5
2 3
S
1
361–1366.
used as starting materials in a ratio of 2:1:1:0.5:6. The reaction
product consisted of transparent colorless polyhedral crystals (∼70%
yield) which were stable to air and moisture. The EDX analysis
revealed the presence of Cs, Nd, P, and S in an approximately ratio
of 3:1:2:8. Compound 3 could also be prepared from reacting the
mixture Cs S , Nd, P S , S in a molar ratio of 2:1:1:6. After
2 3 2 5
treatment of the reaction product (see above), 3 was obtained in
about 90% yield.
(
(
17) Komm, T.; Schleid, T. J. Solid State Chem. 2005, 178, 454–463.
18) Aitken, J. A.; Kanatzidis, M. G. J. Am. Chem. Soc. 2004, 126, 11780–
1
1781.
(
(
(
(
19) Komm, T.; Schleid, T. Z. Anorg. Allg. Chem. 2004, 630, 712–716.
20) Komm, T.; Schleid, T. Z. Kristallogr. Suppl. 2003, 20, 152.
21) Komm, T.; Schleid, T. J. Alloys Compd. 2006, 418, 106–110.
22) McGuire, M. A.; Reynolds, T. K.; DiSalvo, F. J. Chem. Mater. 2005,
7, 2875–2884.
23) Lee, S.; Colombet, P.; Ouvrard, G.; Brec, R. Inorg. Chem. 1988, 27,
291–1294.
24) Klawitter, Y.; Bensch, W.; Wickledder, C. Chem. Mater. 2006, 18,
87–197.
1
(
(
1
3 3 4 4
Preparation of K Nd [PS ] (4). The procedure for the synthesis
1
of 4 is the same as that of 1 except that the molar ratio of K S ,
2 3
7524 Inorganic Chemistry, Vol. 47, No. 17, 2008

K
9
Nd[PS
4 4 3 4 2 3 4 2 3 3 4 4
] , K Nd[PS ] , Cs Nd[PS ] , and K Nd [PS ]
a
Table 1. Technical Details of Data Acquisition and Some Refinement Results
compound
formula
crystal system
space group
a [Å]
1
2
3
4
K9Nd[PS4]4
monoclinic
C2/c
20.1894(16)
9.7679(5)
17.4930(15)
115.66(1)
3109.5(4)
4
K3Nd[PS4]2
monoclinic
P21/c
9.1799(7)
16.8797(12)
9.4828(7)
90.20(1)
1469.4(2)
4
Cs3Nd[PS4]2
monoclinic
P21/n
15.3641(13)
6.8865(4)
15.3902(13)
99.19(1)
1607.5(2)
4
K3Nd3[PS4]4
monoclinic
C2/c
16.1496(14)
11.6357(7)
14.6784(11)
90.40(1)
2758.2(4)
4
b [Å]
c [Å]
ꢀ
[°]
3
V [Å ]
Z
T [K]
220
2.440
4.286
2202
220
2.622
5.697
1100
220
3.559
11.127
1532
220
2.858
7.454
2212
calcd. den. (g.cm-3)
-
1
µ Mo [mm
F(000)
]
2
θ range [°]
5° e 2θ e 56°
5° e 2θ e 56°
-12 e h e 12
-22 e k e 22
-12 e l e 12
3431
5° e 2θ e 56°
-20 e h e 20
-9 e k e 9
-20 e l e 19
3857
5° e 2θ e 56°
-19 e h e 21
-14 e k e 15
-19 e l e 19
3238
index range
-26 e h e 25
-
12 e k e 12
23 e l e 23
-
indep. refl.
3729
refl. [Fo > 4σ(Fo)]
Rint
min/max. transm.
no. parameters
a*
2595
3251
0.0611
0.3073/0.5195
129
0.0680
3131
0.0494
0.1513/0.3293
128
0.0609
2894
0.0381
0.3028/0.3979
121
0.0596
0.0305
0.4457/0.6170
140
0.0583
8.8
b*
4.9
0
0
R1 for Fo > 4σ(Fo)
wR2 for all data
GOF
0.0361
0.1104
1.081
0.0393
0.1061
1.073
3.475/-2.043
0.0343
0.0911
0.993
1.653/-2.150
0.0302
0.0792
0.993
∆
F[e Å-3]
1.218/-1.256
1.677/-2.511
2
a
2
2 2
2 2 1/2
2
2
2
R1 )∑||Fo| - |Fc||/∑|Fo|, wR2 ) [∑(Fo - Fc ) /∑w(Fo ) ] , w ) 1/[σ(Fo ) + (aP) + bP] where P ) (max (Fo ,0) + 2Fc )/3.
BaS, Nd, P
2
S
5
, and S was changed to 1:1:1:6. The melt contained
basis of the systematic absences. At the early stages of the
refinement the reliability factors R1 and wR2 were 0.15 and 0.42.
To improve the refinement the TwinRotMat option in PLATON
transparent platelet crystals in 90% yield. The crystals were stable
in dry air for several weeks. The EDX analysis indicated the
presence of K, Nd, P, and S in the approximate ratio of 3:3:4:16.
2
6
was used to determine the twin law for the crystal (-1 0 0, 0 1 0,
0 0 1) or (1 0 0, 0 -1 0, 0 0 -1). A separate set of batch scale
factors was refined. With this strategy the reliability factors were
significantly improved. In the final stage all atoms were refined
with anisotropic displacement parameters yielding R1 ) 0.0393
and wR2 ) 0.1061. The maximum and minimum peaks in the final
2.3. Physical Measurements. X-ray Crystallography. All single
crystal X-ray investigations were performed using an Imaging Plate
Diffraction System (IPDS-1; Mo KR-radiation; λ ) 0.71073 Å)
equipped with a low temperature device from Oxford Cryosystem.
The crystals were mounted on top of glass fibers and bathed in
cold nitrogen stream during data collection. The raw intensities were
treated in the normal way by Lorentz, polarization, and numerical
3
Fourier difference map were 3.475 and -2.043 e/Å .
3 4 2 3 3 4 4
Cs Nd[PS ] (3) and K Nd [PS ] (4). A transparent colorless
3
absorption corrections. All structures were solved with direct
methods using SHELXS-97 and refined against F
platelet crystal with dimensions of 0.15 × 0.10 × 0.06 mm for 3
2
o
using SHELXL-
and a transparent colorless polyhedron with dimension 0.13 × 0.09
2
5
3
9
7 of the SHELXTL program package.
Nd[PS (1). A transparent pale red platelet crystal with
× 0.07 mm for 4 were selected. According to the systematic
K
9
4
]
4
1
absences, 3 crystallizes in P2 /n and 4 in C2/c. All atoms in both
3
dimensions of 0.13 × 0.10 × 0.08 mm was manually selected
from the reaction product. From systematic extinctions, the space
group C2/c was chosen. The structure refinement revealed unusually
anisotropic displacement parameters for the Nd atoms. Almost all
P and S sites showed non-positive principal mean square atomic
displacements. Introducing a disorder model with mixed Nd/K
occupancies on the Nd sites, the refinement resulted in 35.2% K
on the Nd(1) site and 56.1% K on the Nd(2) position. The final
compounds were subsequently refined with anisotropic displacement
parameters.
Technical details of the data acquisition as well as some
refinement results for all compounds are summarized in Table 1.
Selected bond lengths and angles are given in Tables 2-5.
Further details of the crystal structure investigation can be
obtained from the Fachinformationszentrum Karlsruhe, 76344
Eggenstein-Leopoldshafen, Germany, (fax: (49) 7247-808-666;
E-mail: crysdata@fiz-karlsruhe.de) on quoting the depository
refined composition was K8.91(1)Nd1.09(1)[PS
4
]
4
. In contrast to
1
0
K
9
Ce[PS
4
]
4
,
no evidence of merohedrally twinning was found.
9 4 4 3 4 2
number CSD-41911 (K Nd[PS ] ), CSD-41913 (K Nd[PS ] ), CSD-
The refinement was also carried out in the space group C2 with
twinning by an inversion center (Flack parameter x ) 0.0(8)). But
no essential differences of the final structural features were found,
especially the Nd/K disorder was not removed in the non-
centrosymmetric space group.
41912 (Cs Nd[PS ), CSD-41914 (K
3
4
]
2
3
Nd [PS ).
3
4 4
]
Infrared Spectroscopy
Infrared spectra in the mid infrared (MIR) region
-
1
-1
(
4000-400 cm , 2 cm resolution, 293 K) were recorded
K
3
Nd[PS
dimensions of 0.14 × 0.09 × 0.07 mm was manually selected
from the reaction product. Space group P2 /c was chosen on the
4 2
] (2). A transparent colorless platelet crystal with
on a Genesis FT-spectrometer (ATI Mattson). The samples
were ground with dry KBr into fine powders and pressed
into transparent pellets. Infrared spectra in the far infrared
3
1
(
25) Sheldrick, G. M. SHELXTL, version 5.10; Bruker Analytical X-ray
Instruments, Inc.: Madison, WI, 1998.
(26) Spek, A. L. J. Appl. Crystallogr. 2003, 36, 7–13.
Inorganic Chemistry, Vol. 47, No. 17, 2008 7525

Wu and Bensch
Table 2. Selected Bond Lengths (Å) and Angles (deg) for K9Nd[PS4]4
Table 4. Selected Bond Lengths (Å) and Angles (deg) for Cs3Nd[PS4]2
Environment of Nd
Environment of Nd
Nd(1)-S(3) × 2
Nd(1)-S(7) × 2
Nd(1)-S(4) × 2
Nd(1)-S(8) × 2
3.0557(10)
3.0584(11)
3.0637(13)
3.0689(13)
S(3)-Nd(1)-S(3)
S(3)-Nd(1)-S(7)
S(7)-Nd(1)-S(7)
S(7)-Nd(1)-S(4)
S(3)-Nd(1)-S(8)
S(4)-Nd(1)-S(8)
S(2)-Nd(2)-S(2)
S(2)-Nd(2)-S(6)
S(6)-Nd(2)-S(6)
S(2)-Nd(2)-S(8)
S(6)-Nd(2)-S(4)
S(8)-Nd(2)-S(4)
150.63(4)
124.10(3)
150.61(3)
123.57(3)
123.46(3)
171.68(2)
149.70(4)
123.00(3)
149.51(4)
123.78(3)
123.80(3)
171.95(2)
Nd(1)-S(8)
Nd(1)-S(3)
Nd(1)-S(2)
Nd(1)-S(4)
Nd(1)-S(1)
Nd(1)-S(7)
Nd(1)-S(4)
Nd(1)-S(6)
2.8766(13)
2.8792(14)
2.9041(13)
2.9312(13)
2.9321(13)
2.9473(12)
3.0655(12)
3.1698(15)
S(8)-Nd(1)-S(2)
S(3)-Nd(1)-S(2)
S(8)-Nd(1)-S(4)
S(8)-Nd(1)-S(1)
S(3)-Nd(1)-S(1)
S(2)-Nd(1)-S(7)
S(4)-Nd(1)-S(7)
S(1)-Nd(1)-S(4)
S(7)-Nd(1)-S(4)
100.66(4)
142.05(4)
141.03(4)
138.79(4)
129.48(4)
139.88(4)
118.91(4)
135.01(4)
137.70(3)
Nd(2)-S(2) × 2
Nd(2)-S(6) × 2
Nd(2)-S(8) × 2
Nd(2)-S(4) × 2
3.1085(11)
3.1091(11)
3.1681(14)
3.1697(14)
Environment of P
P(1)-S(1)
P(1)-S(2)
P(1)-S(3)
P(1)-S(4)
2.0361(17)
2.0424(17)
2.0445(18)
2.0535(17)
S(1)-P(1)-S(2)
S(1)-P(1)-S(3)
S(1)-P(1)-S(4)
S(2)-P(1)-S(3)
S(2)-P(1)-S(4)
S(3)-P(1)-S(4)
S(5)-P(2)-S(6)
S(5)-P(2)-S(7)
S(5)-P(2)-S(8)
S(6)-P(2)-S(7)
S(6)-P(2)-S(8)
S(7)-P(2)-S(8)
109.50(8)
109.52(7)
114.72(7)
111.12(7)
105.62(7)
106.30(7)
117.86(9)
112.21(8)
111.28(8)
104.04(7)
103.57(7)
106.96(8)
Environment of P
P(1)-S(1)
P(1)-S(2)
P(1)-S(3)
P(1)-S(4)
2.0218(13)
2.0287(14)
2.0394(14)
2.0552(13)
S(1)-P(1)-S(2)
S(1)-P(1)-S(3)
S(1)-P(1)-S(4)
S(2)-P(1)-S(3)
S(2)-P(1)-S(4)
S(3)-P(1)-S(4)
S(5)-P(2)-S(6)
S(5)-P(2)-S(7)
S(5)-P(2)-S(8)
S(6)-P(2)-S(7)
S(6)-P(2)-S(8)
S(7)-P(2)-S(8)
110.37(6)
111.23(6)
111.76(6)
108.18(6)
109.13(6)
106.00(6)
110.31(6)
111.22(6)
111.77(6)
108.22(6)
109.03(3)
106.13(6)
P(2)-S(5)
P(2)-S(6)
P(2)-S(7)
P(2)-S(8)
2.0057(19)
2.0431(19)
2.0512(17)
2.0594(17)
P(2)-S(5)
P(2)-S(6)
P(2)-S(7)
P(2)-S(8)
2.0239(13)
2.0290(14)
2.0363(14)
2.0559(13)
Table 5. Selected Bond Lengths (Å) and Angles (deg) for K3Nd3[PS4]4
Environment of Nd
Nd(1)-S(2)
2.8236(11)
2.8461(12)
2.8475(11)
2.8800(11)
2.9852(11)
3.0241(10)
3.0491(11)
3.0826(11)
2.8980(11)
2.8984(11)
2.9183(10)
3.0546(10)
S(2)-Nd(1)-S(3)
S(3)-Nd(1)-S(8)
S(5)-Nd(1)-S(8)
S(3)-Nd(1)-S(7)
S(5)-Nd(1)-S(4)
S(2)-Nd(1)-S(7)
S(4)-Nd(1)-S(7)
S(8)-Nd(1)-S(4)
S(7)-Nd(1)-S(4)
S(1)-Nd(2)-S(1)
S(6)-Nd(2)-S(8)
S(1)-Nd(2)-S(8)
S(8)-Nd(2)-S(8)
141.15(3)
110.13(3)
144.10(3)
141.86(3)
145.75(3)
140.99(3)
112.87(3)
133.92(3)
129.84(3)
148.40(4)
140.70(3)
110.10(3)
149.88(4)
Table 3. Selected Bond Lengths (Å) and Angles (deg) for K3Nd[PS4]2
Nd(1)-S(3)
Environment of Nd
Nd(1)-S(5)
Nd(1)-S(6)
Nd(1)-S(7)
Nd(1)-S(2)
Nd(1)-S(8)
Nd(1)-S(4)
Nd(1)-S(4)
Nd(1)-S(3)
Nd(1)-S(8)
2.8560(17)
2.9029(16)
2.9340(18)
2.9469(19)
2.9556(15)
3.0265(18)
3.1567(19)
3.2307(18)
S(6)-Nd(1)-S(7)
S(2)-Nd(1)-S(8)
S(6)-Nd(1)-S(4)
S(2)-Nd(1)-S(4)
S(7)-Nd(1)-S(4)
S(8)-Nd(1)-S(4)
S(7)-Nd(1)-S(3)
S(2)-Nd(1)-S(3)
S(3)-Nd(1)-S(8)
143.37(5)
134.40(5)
143.07(5)
124.91(5)
133.98(5)
135.85(5)
124.30(4)
132.08(5)
147.72(5)
Nd(1)-S(8)
Nd(1)-S(7)
Nd(1)-S(4)
Nd(1)-S(7)
Nd(1)-S(4)
Nd(2)-S(6) × 2
Nd(2)-S(1) × 2
Nd(2)-S(8) × 2
Nd(2)-S(4) × 2
Environment of P
P(1)-S(1)
P(1)-S(2)
P(1)-S(3)
P(1)-S(4)
1.996(2)
2.033(2)
2.041(2)
2.059(2)
S(1)-P(1)-S(2)
S(1)-P(1)-S(3)
S(1)-P(1)-S(4)
S(2)-P(1)-S(3)
S(2)-P(1)-S(4)
S(3)-P(1)-S(4)
S(5)-P(2)-S(6)
S(5)-P(2)-S(7)
S(5)-P(2)-S(8)
S(6)-P(2)-S(7)
S(6)-P(2)-S(8)
S(7)-P(2)-S(8)
111.60(10)
117.68(12)
111.33(10)
108.62(11)
104.64(10)
101.82(9)
110.42(10)
109.53(10)
112.65(10)
109.44(10)
108.91(11)
105.75(9)
Environment of P
P(1)-S(1)
P(1)-S(2)
P(1)-S(3)
P(1)-S(4)
2.0170(15)
2.0299(16)
2.0350(14)
2.0810(15)
S(1)-P(1)-S(2)
S(1)-P(1)-S(3)
S(1)-P(1)-S(4)
S(2)-P(1)-S(3)
S(2)-P(1)-S(4)
S(3)-P(1)-S(4)
S(5)-P(2)-S(6)
S(5)-P(2)-S(7)
S(5)-P(2)-S(8)
S(6)-P(2)-S(7)
S(6)-P(2)-S(8)
S(7)-P(2)-S(8)
111.52(7)
110.83(7)
106.45(6)
109.56(7)
107.72(6)
110.69(6)
111.92(7)
109.61(6)
109.54(7)
109.85(7)
107.83(6)
107.99(6)
P(2)-S(5)
P(2)-S(6)
P(2)-S(7)
P(2)-S(8)
2.008(2)
2.035(2)
2.042(2)
2.066(2)
P(2)-S(5)
P(2)-S(6)
P(2)-S(7)
P(2)-S(8)
2.0253(16)
2.0283(14)
2.0464(15)
2.0659(15)
-
1
(
FIR) region (550-80 cm ) were collected on an ISF-66
and pressed into a pellet that is fixed on a vibrating sample
holder cooled at about 15 K by a closed cycle He refrigerator
(Model 22/8300, CTI) as described elsewhere to prevent
heating of the sample. The spectra have not been corrected
for spectrometer and detector response.
device (Bruker) with finely powdered samples pressed in
polyethylene pellets.
2
7
Raman Spectroscopy
Solid-State Ultraviolet (UV)-Visible(vis)-Near-IR Spec-
troscopy. UV/vis/NIR diffuse reflectance spectra at 293 K were
recorded on a Cary 5 spectrometer (Varian Techtron Pty.). The
spectrometer was equipped with an Ulbricht sphere (Diffuse
reflectance accessory; Varian Techtron Pty.). The inner wall of
the Ulbricht sphere (diameter 110 mm) was covered with a
PTFE layer of 4 mm thickness. A PbS detector (NIR) and a
photomultiplier (UV/vis) were attached to the Ulbricht sphere.
FT-Raman spectra were recorded on an ISF-66 spectrom-
eter (Bruker) equipped with an additional FRA 106 Raman
module and a diode-pumped Nd/YAG laser (λ ) 1064 nm;
Adlas). Finely powdered samples were pressed into the small
hole of Al sample holders. The measuring range was -2500
-
1
-1
to 3500 cm with a resolution of 2 cm at 293 K.
Conventional Raman spectra were measured on a multichan-
nel XY Spectrometer (Dilor) equipped with a nitrogen cooled
CCD detector. Excitation of the Raman spectra was obtained
4
The samples were ground together with BaSO and
prepared as a flat specimen. Resolution was 1 nm for the
+
+
by selected laser lines of an Ar /Kr laser type (Spectra
Physics). The finely powdered sample was mixed with KBr
(27) Preetz, W.; Parzich, E. Z. Naturforsch. 1993, 48b, 1737–1741.
7526 Inorganic Chemistry, Vol. 47, No. 17, 2008

9 4 4 3 4 2 3 4 2 3 3 4 4
K Nd[PS ] , K Nd[PS ] , Cs Nd[PS ] , and K Nd [PS ]
UV/vis range and 2 nm for the NIR range. The measuring
range was 250-2000 nm. BaSO was used as standard for
00% reflectance. Absorption data were calculated from the
4
1
2
8
reflectance data using the Kubelka-Munk function. The
approximate band gap was determined as the intersection
point between the energy axis and the line extrapolated from
2
the linear part of the absorption edge in a (F(R)) versus
energy plot.
3
. Results and Discussion
.1. Synthesis. Syntheses of compounds 1 and 4 were
achieved by reacting mixtures of K /Nd/P /S at 973 K
3
S
2 3
2 5
S
in 1:1:1:6 and 2:1:0.5:6 molar ratios, respectively. 1 was
obtained as transparent pale red platelets and 4 as colorless
platelets. The reactions involve the oxidative dissolution of
Nd in the basic melt and the subsequent coordination of the
Figure 1. Crystal structure of K9Nd[PS4]4 with perspective view along
[010].
3
-
trivalent Nd cations by the [PS
parameters were varied by changing the amounts of K
and P . Increasing the basicity of the flux by increasing
and decreasing P , led to the formation of compound
. All attempts to obtain 1 in higher yields were unsuccessful,
4
]
anions. The reaction
2 3
S
2 5
S
K S
2 3
2 5
S
1
and the products always contained some amount of com-
pound 2.
Compounds 2 and 3 were isolated from reaction mixtures
2 3
containing BaS or As S , respectively. With theses syntheses
the possibility of the formation of mixed Nd alkali-metal
alkaline-metal (Ba) thiophosphates and Nd alkali-metal
thiophosphate-thioarsenate compounds via the flux method
was explored. 2 was obtained in a reasonable yield by
Figure 2. Interconnection of the {Nd[PS4]4} units into chains with atomic
labeling.
dodecahedra. The Nd-S distances range from 3.0557(10)
to 3.0689(13) Å for Nd(1) and 3.1085(11) to 3.1697(14) Å
for Nd(2) (see Table 2). The average of 3.06 Å for Nd(1)-S
and 3.14 Å for Nd(2)-S are longer than the average Nd-S
reacting a mixture of K
of 2:0.25:1:1:6. On increase of the fraction of BaS, the two
compounds KBaPS and NdS (EDX) were identified as main
products. The reactions with SrS and CaS were also explored.
Under the same reaction conditions, KSrPS (KCaPS ) and
2 3 2 5
S /BaS/Nd/P S /S with molar ratio
4
2
2a,f
distances of 2.96 Å in NdPS
4
3 4 2
and of 3.00 Å in K Nd[PS ]
4
4
(
see below). The trigonal dodecahedra share common edges
NdS
2
(EDX) could be identified.
1
3-
with [PS
4
] tetrahedra forming
∞ 4 2
{Nd(PS ) }
chains (Figure
3
was obtained applying a mixture Cs S /Nd/P S /As S /S
2 3 2 5 2 3
2
).
But because of the statistical occupation of Nd and K sites,
(
2 3
molar ratio 2:1:1:0.5:6). Increasing the fraction of As S
led to the formation of yellow glassy products along with 3.
After these syntheses several experiments were performed
in the Cs S /Nd/P S /S system. The best results with a yield
2 3 2 5
9
-
isolated {Nd[PS
4 4
] }
units occur occasionally. The chains
+
are separated by the four crystallographically distinct K
cations, which are coordinated in an irregular environment
by 8 or 10 S atoms with distances from 3.2291(15) to
of about 90% were obtained using Cs
2 3 2 5
S /Nd/P S /S in a
molar ratio of 2:1:1:6.
3
.9981(14) Å.
Nd[PS
clinic space group P2
3
.2. Crystal Structures. K Nd[PS ] (1) crystallizes in the
9 4 4
K
3
4
]
2
(2) (see Figure 3) crystallizes in the mono-
/c with one crystallographically
monoclinic space group C2/c with two crystallographically
independent P, four unique K, eight unique S atoms that are
located on general positions. The two unique Nd atoms are
also on general sites which show a mixed occupancy with
1
independent Nd, two unique P, three unique K, and eight
unique S atoms that are located on general positions.
2
contains linear chains formed by bicapped {NdS
8
}
K cations. The structure of K
9 4 4
Nd[PS ] (1) is depicted in
trigonal prisms which are joined through edge sharing with
Figure 1 and can be viewed as an ordering variant of the
3
-
1
0
8 4
neighboring {NdS } polyhedra and with [PS ] tetrahedra.
K
9
Ce[PS
along [001] as twinning element.
Compared to the Ce compound where only 3% of K are
4 4
] structure type, which possesses a 2-fold axis
3
+
Figure 4 displays the coordination around the Nd ions in
+
the chain running along the a-axis. All eight S atoms bound
3
+
3-
3
+
to one Nd are part of [PS
4
]
anions. The Nd-S bond
located on the Ce positions and vice versa, K
9 4 4
Nd[PS ]
lengths range from 2.8560(17) to 3.2307(18) Å with an
average of 3.00 Å (Table 3). The two longest distances in
(
1) shows a more complicated mixed-cation occupation
3
+
pattern. Both Nd ions are coordinated by eight S atoms
through four edge-sharing [PS ] tetrahedra to form trigonal
the {NdS
to the capping S atoms (S(3) and S(8), see Figure 4),
respectively. Each {NdS } polyhedron shares two of its edges
8
} polyhedron at 3.1568(19) and 3.2307(18) Å are
4
(
28) Kulbelka, P.; Munk, F. Z. Tech. Phys. 1931, 12, 593–601.
8
Inorganic Chemistry, Vol. 47, No. 17, 2008 7527

Wu and Bensch
is almost parallel to the chain axis resulting in an almost
perfect tetrahedral angle of 108.86(5)° for Nd(1)-S(8)-Nd(1)
around the bridging S(8) atom. The different orientations of
the tetrahedra lead to two different Nd-Nd distances. For
Nd-Nd bridged by S(8) the separation of 5.0276(6) Å is
significantly larger than that with the S(4) bridge of 4.2564(6)
4
Å. Both separations are slightly shorter than that in Nd[PS ]
2
f
(
5.420 Å) but much longer than the sum of the ionic radius
3+
33
of Nd (1.109 Å). The P-S bond lengths and bond angles
3
+
vary depending on how S atoms are bound to Nd . In
P(1)S ], the P(1)-S(1) bond length is 1.996(2) Å with
corresponding S(1)-P(1)-S(2)/(3)/(4) angles of 111.60(10)°,
17.68(12)°, and 111.33(10)°, respectively, while the
P(1)-S(2)/(3)/(4) bonds are longer with 2.033(2), 2.041(2),
.059(2) Å and the corresponding angles are obviously
smaller (S(2)-P(1)-(3): 108.62(11)°, S(2)-P(1)-S(4):
[
4
1
2
1
04.64(10)°, S(3)-P(1)-S(4): 101.82(9)°). These differences
of the bond lengths and angles may be a result of the partial
double bond character of the terminal P(1)-S(1) bond. The
Figure 3. Perspective view of K3Nd[PS4]2 (2) crystal structure down [100].
same trend is observed for [P(2)S
shorter (2.008(2) Å) than P(2)-S(6)/(7)/(8) (2.035(2), 2.042(2),
.066(2) Å), whereas S(5)-P(2)-S(6)/(7)/(8) bond angles
4
], with P(2)-S(5) being
2
(
7
110.42(10)°, 109.53(10)°, 112.65(10)°) are larger than S(6,
, 8)-P(2)-S(6, 7, 8) (e.g., S(7)-P(2)-S(8): 105.75(9)°)
+
(Table 3). The charge compensating K ions reside in the
3
-
voids between the {Nd[PS
4 2
] }
chains, where the shortest
interchain S-S distance is 3.760(2) Å. All K cations are in
an irregular coordination environment of nine S atoms with
K-S distances from 3.147(2) to 3.980(3) Å.
The structure of compound 2 can be compared with that
1
2
9
of K
La[PS ]
3 4 2
3 4 2
and K Ce[PS ] . A common feature of the
Figure 4. Perspective view of the {Nd[PS4]2}3 chain. The {NdS8}
polyhedra are linked to each other through edge sharing to form an infinite
chain along [100].
-
three structures is an alternating short-long metal to metal
separation along the one-dimensional chains. The La-La
distances in K
the analogous Ce-Ce separations in K
.022(1) and 4.211(1) Å. In the La/Ce compounds the rare
La[PS ]
3 4 2
are 5.045(2) and 4.217(2) Å whereas
3
Ce[PS amount to
4 2
]
5
earth ions are surrounded by nine S atoms with average bond
lengths of 3.076(2) (La) and 3.058(2) (Ce), whereas in 2
3
+
Nd is in an environment of eight S atoms with a mean
Nd-S bond length of 3.001(3) Å. The different coordination
numbers in the three compounds is caused by the different
Figure 5. Interconnection of the {NdS8} polyhedra in K3Nd[PS4]2. Dashed
black lines highlight the polyhedra. [PS4] groups are omitted for clarity.
orientations of the bridging [PS
As can be seen in Figure 4, the P(1)S tetrahedron is turned
4
] tetrahedra along the chains.
(
S(4)-S(4) and S(8)-S(8)) with two other polyhedra on
1
3-
4
opposite sides of the polyhedra to form
chains.
This connection scheme is responsible for the kink-like
shape of the chains as depicted in Figure 5.
∞ 4 2
{Nd(PS ) }
away from the {NdS
between Nd(1) and S(3) is enlarged to 3.479(2) Å. In
La[PS and K Ce[PS , the corresponding distances are
3.118(2) and 3.149(2) Å, being reasonably short for bonding
interactions and the formation of LaS /CeS polyhedra.
8
} polyhedron so that the distance
K
3
]
4 2
3
4 2
]
3
-
The two distinct [PS
4
]
anions are each coordinated to
Nd3+ ions by one S atom (S(2), S(3) for P(1) and S(6), S(7)
for P(2)) for each neighboring Nd , whereas the third S
atom (S(4) and S(8)) acts as a bridge to both Nd . The fourth
S atom of each thiophosphate anion (S(1) and S(5)) remains
terminal. An obvious difference of the two [PS
is their orientation with respect to the chain axis. The [P(1)S
tetrahedron shares two edges with {NdS
the Nd(1)-S(4)-Nd(1) angle of 90.71(5)°. The [P(2)S
tetrahedron has also two common edges with neighboring
{
9
9
3+
3
+
Despite the identical ratio of alkali ions to Nd and
thiophosphate ions, Cs Nd[PS (3) crystallizes with a different
one-dimensional anionic structure type. The main structural
3+
3
4 2
]
1
3-
3
-
4
]
anions
feature is a
∞
{Nd[PS
4
]
2
}
zigzag chain running along the
4
]
crystallographic b-axis which is displayed in Figure 6.
3
+
8
} polyhedra, with
The chain contains one independent Nd ion but two
3
-
]3- group has
4
]
different bridging [PS
4
]
units. The [P(1)S
bonds to three Nd acting as a bridging unit while the
4
3
+
3
-
8
NdS } polyhedra, but the trigonal face of the tetrahedron
[P(2)S
4
]
tetrahedron is only attached to one Nd atom via
7528 Inorganic Chemistry, Vol. 47, No. 17, 2008

9 4 4 3 4 2 3 4 2 3 3 4 4
K Nd[PS ] , K Nd[PS ] , Cs Nd[PS ] , and K Nd [PS ]
(see Table 4). In contrast, the P(2)-S bonds scatter over a
larger range (P(2)-S: 2.006(2)-2.059(2) Å), and the angles
S-P(2)-S (103.6(1)-117.9(1)°) indicate a more severe
distortion of the tetrahedron. Again, the shortest bond length
is found to the terminal atom S(5). The chains are separated
+
by Cs cations residing on three different sites. All Cs atoms
are coordinated by nine S atoms in an irregular environment
with Cs-S distances from 3.4255(13) to 3.8917(15) Å.
K Nd [PS ] (4) crystallizes in the monoclinic space group
3 3 4 4
C2/c with two crystallographically independent Nd, K, P,
and eight unique S atoms. In the structure two different
3
-
{
NdS
The Nd(1) atom is surrounded by eight S atoms yielding a
bicapped trigonal prism. The {Nd(1)S } polyhedra are linked
by common edges of neighboring {Nd(1)S } polyhedra
chain running along
8
} polyhedra share edges with four [PS
4
]
tetrahedra.
8
8
1
3-
Figure 6. Perspective view of the Nd[PS4]23- anionic chain in Cs3Nd[PS4]2.
∞ 4 2
building a straight {Nd(1)[PS ] }
[
110] and [ 1j 10] as shown in Figure 8a,b.
The Nd(2) atom is also surrounded by eight S atoms of
four edge sharing [PS
4
] tetrahedra, but in this case a trigonal
} poly-
∞ 4 2
{Nd(1)[PS ] } chains via common corners
dodecahedron is formed (Figure 8c). The {Nd(2)S
8
1
3-
hedra join the
into a three-dimensional network
), with the tunnels running parallel to [110] and [ 1j 10]. The
3
3-
∞ 3 4
{Nd [PS ]
4
}
(Figure
9
dimension of the tunnels is about 26.6 × 6.2 Å measured
from coordinate to coordinate.
The Nd-S bonds (2.8236(11)-3.0491(11) Å for Nd(1);
2
.8980(11)-3.0546(10) Å for Nd(2); average for both: 2.94
2a,f,15,21
Å) are in the range observed in literature
and also in
the other three compounds. Five Nd(1)-S and six Nd(2)-S
distances are relatively short and below 3.0 Å (Table 5). The
remainingNd-Sbonds(Nd(1)-S(4),Nd(1)-S(7);Nd(2)-S(4))
are significantly longer (Table 5). The P-S bond lengths
Figure 7. Interconnection of {NdS8} polyhedra in 3. Dashed lines highlight
3
-
the polyhedra. [PS4] anions are omitted for clarity.
range from 2.0170(15) to 2.0810(15) Å for [P(1)S
.0253(16) to 2.0659(15) Å for [P(2)S ] (Table 5) with
corresponding angles (106.45(6)-111.52(7)° for [P(1)S ];
07.83(6)-111.92(7)° for [P(2)S ]) which indicate only a
slight deviation from the ideal tetrahedral geometry. The
cationic surrounding of the [P(1)S ] and [P(2)S ] tetrahedra
is almost identical. Both share three edges with two
8
Nd(1)S } bicapped trigonal prisms and one {Nd(2)S }
4
] and from
2
4
three S atoms. The anionic chains are well separated by Cs+
cations.
In contrast to the linear chain in compound 2, the bicapped
4
1
4
{
µ
NdS
8
} trigonal prisms in 3 are linked by common corners
], and the three remaining S atoms of
4
4
2
-S(4) of [P(1)S
4
3
+
[
P(1)S
P(1)S
NdS
with the other two {NdS
around the µ -S(4) atom is 125.90°. The basal planes of
bicapped {NdS } trigonal prisms are nearly parallel to the
chain direction and perpendicular to the [101] direction
4
] have each only one bond to a Nd ion. Hence, the
{
8
[
{
4
] tetrahedron has one common corner (S(1)) with one
trigonal dodecahedron and three K cations. The K(1) ion is
located at the tunnel edges having contacts to eight S atoms
in an irregular environment with K-S distances ranging from
8
} polyhedron and two edges (S(2)-S(4) and S(3)-S(4))
} polyhedra. The Nd-S-Nd angle
8
2
3
.209(2) to 3.588(2) Å (average: 3.37 Å). The K(2) ion is
8
situated at the center of the tunnel in a distorted cubic
environment with K(2)-S distances between 3.190(1) and
(
Figure 7).
3
.368(1) Å (average: 3.28 Å). Compared to the Nd, P, and
The Nd-S bonds range from 2.8766(13) to 3.1698(15) Å
+
S atoms, the K ions have larger displacement parameters
which may be due to a partial static disorder caused by a
relatively poor fit of the ionic radius of K and the
with an average of 2.96 Å. Like in the other compounds the
bond lengths to capping atoms S(4) and S(6) are obviously
longer. (Nd-S(4): 3.0655(12) Å and Nd-S(6): 3.1698(15)
+
Å). The [P(2)S
4
] tetrahedron shares one triangular face with
dimensions of the tunnel.
one {NdS } polyhedron, and the fourth S atom (S(5)) remains
8
Although many complex rare earth thiophosphates have
been synthesized and characterized during the past decade,
only few of these compounds crystallize with three-
dimensional anionic frameworks. Compounds with anionic
terminal. The P-S bond lengths (2.0057(19)-2.0594(17) Å;
average: 2.042 Å) show a clearly more narrow distribution
than those in 2. The P(1)-S bonds range from 2.036(2) to
2
.054(2) Å and the deviations of the S-P-S bond angles
chains are K
3
Ce[PS
4
]
2
, K
3
La[PS
4 2
] and the selenides
12b
8
fromtheidealtetrahedralvaluearesmall(105.6(1)°-114.7(1)°)
3 4 2
K La[PSe ] ,
Rb Ce[PSe ] , and Cs Gd[PSe ] , which are
3 4 2 3 4 2
Inorganic Chemistry, Vol. 47, No. 17, 2008 7529

Wu and Bensch
1
3-
Figure 8. (a) Section of the ∞{Nd(1)[PS4]2} chain in K3Nd3[PS4]4. The {NdS8} polyhedra are linked via edge sharing to form an infinite chain along
110] and [ 1j 10]. (b) View of the {Nd(1)S8} bicapped trigonal prism. The trigonal prism is outlined with dashed lines for clarity. The long bonds are to the
[
capping atoms S(4) and S(7); (c) View of the {Nd(2)S8} trigonal dodecahedron. Two basal triangles are outlined with dashed lines.
characterized by linear anions showing a relation to the
anions in compound 2.
3 3 4 4 3 3 4 4
While Rb Pr [PS , Rb Er [PS ] , and K Nd [PS ] have
17
3
3
]
4 4
the same formulas, three different structures with two
different dimensionalities are observed. One important dif-
ference between the structures is the arrangement and
1
3-
orientation of
∞
{Ln[PS
4
]
2
}
chains. In K
{Nd(1)[PS
}3- chains:
chain along the [110] direction and a
3 3 4 4
Nd [PS ] there
1
are two types of
∞
4
]
2
a
1
3-
∞
{Nd(1)[PS
4 2
] }
1
3-
1
3-
chain along [1
j10]. The
{Nd(1)[PS ] }
∞ 4 2
∞
{Nd(1)[PS
4
]
2
}
chains running along [110] can be viewed as pseudolayers
1
3-
at z ≈ 0, whereas the
form pseudolayers at z ≈ 0.5 as shown in Figure 10. Both
are linked by {Nd(2)S
} polyhedra at z ≈ 0.25 and 0.75 to
4 4
form the three-dimensional framework. But in Rb Er [PS ]
∞
{Nd(1)[PS
4
]
2
}
chains along [1
j10]
8
Figure 9. View of the structure of K3Nd3[PS4]4 with view along [110].
3
3
1
3-
there is only one type of
is running parallel to [100]. The ∞{Er(2,3)[PS4]2} chains
∞
{Er(2,3)[PS
4
2
] }
chain, which
2
9
1
3-
isostructural to K
3 4
Pu[PS ]
2
,
while three-dimensional net-
2
i,11
works were reported for LiEuPQ
4
(Q ) S, Se)
The anionic chains in
(A ) alkali metal, Q ) S, Se) are very similar
at y ≈ 0.25 and 0.75 are connected by {Er(1)S
8
} polyhedra
1
9
18
3 5 4 6
Cs Pr [PS ] ,
6 3 4 5
and K Yb [PS ] .
at y ≈ 0.25 and 0.75 to form two different two-dimensional
2
3-
A Ln[PQ ]
3 4 2
∞ 3 4 4
{Er [PS ] }
layers, respectively. On the other hand, the
to that of compound 2 but distinctly different from the chains
dimensionality of anionic frameworks increases as the alkali
metal cation size decreases which is the well-known coun-
observed for 3. In 2 and the above-mentioned compounds,
3
2
3
+
terion effect. In the three structures this effect takes place
the Ln ions are in bicapped trigonal prismatic chalcogen
coordination and the linkage between the prisms and the two
+
because of the size differences between K (1.51 Å (CN )
+
+
8
K
)) and Rb (1.61 Å (CN ) 8)). The size of K in
4
crystallographically independent tetrahedral [PQ ] groups
lead to the formation of linear chains, whereas zigzag chains
+
3
Nd
3
4
[PS ]
Er
4
(4) is smaller than that of Rb in Rb
Pr
3 3
[PS
]
4 4
and Rb
3
3 4 4
[PS ] , allowing a denser packing of the anionic
are formed in compound 3. The only other example of this
3
0
part of the structures. But this density increase can only be
realized when the volume of the anions is also reduced.
Assuming a constant volume of the anionic part of the
formula type with zigzag chains is K
3 4
Bi[PS ]
2
.
Its polar
character is more pronounced because of the steric ef-
fect of the lone pair of the Bi(III) ion. The recently re-
+
3
1
structure the replacement of the larger Rb by the smaller
3 4 2
ported thioarsenates K Ln[AsS ] (Ln ) Nd, Sm, Gd) are
+
K should lead to a destabilization of the structure because
of repulsive interanionic forces. The anionic volume can be
decreased by increasing the connectivity of the atoms and
(
29) Hess, R. F.; Gordon, P. L.; Tait, D.; Abney, K. D.; Dorhout, P. K.
J. Am. Chem. Soc. 2002, 124, 1327–1333.
(
(
30) McCarthy, T.; Kanatzidis, M. G. J. Alloys Compd. 1996, 236, 70–85.
(32) Kim, K.-W.; Kanatzidis, M. G. J. Am. Chem. Soc. 1998, 120, 8124–
8135.
31) Wu, Y.-D.; N a¨ ther, C.; Bensch, W. Inorg. Chem. 2006, 45, 8835–
8
837.
(33) Shannon, R. D. Acta Crystallogr. 1976, A32, 751–767.
7530 Inorganic Chemistry, Vol. 47, No. 17, 2008

9 4 4 3 4 2 3 4 2 3 3 4 4
K Nd[PS ] , K Nd[PS ] , Cs Nd[PS ] , and K Nd [PS ]
Figure 10. (a) View of the layer 1∞{Nd(1)[PS4]2}3- in 4 along [110]; (b) view of the 2∞{Er3[PS4]4}3- layer down [010].
by association of discrete components into larger building
units to increase the dimensionality. Therefore, the
3-
3 4 4
{Ln [PS ] }
framework in 4 is three-dimensional, whereas
the anionic part of Rb
dimensional.
3 3 4 4 3 3 4 4
Pr [PS ] and Rb Er [PS ] is two-
3.3. Spectroscopic Properties. The IR and Raman spectra
of 2, 3, and 4 are shown in Figure 11 jointly with the
corresponding vibrational wavenumbers and their assign-
ments based for simplicity on local T symmetry. The
d
vibrational Raman spectra have been excited with two
different wavelengths (488.0 and 496.5 nm) to discriminate
them by their constant Raman shifts from potentially present
luminescence spectra. No significant resonance Raman effect
has been detected, and small differences in the intensity
pattern between the different excitation wavelengths are
instead presumed to result essentially from not corrected
absorption.
For every alkali neodymium thiophosphate, the only
3-
vibrationally active species is the [PS
4
]
anion, and therefore
their vibrational spectra are closely related. In the range from
-
1
2
00 to 650 cm (Figure 11), bands attributed to the internal
3-
vibrations of the [PS
rotations and translations of the [PS
4
]
anion are observed, while those for
3-
4
]
anion and the cations
in the crystal lattices are at lower energy. For experimental
reasons, these external vibrations have not been studied
systematically. According to the group theoretical selection
rules for tetrahedral molecules with T
symmetric and antisymmetric P-S stretching vibrations ν
and ν of symmetry a and t and both S-P-S bending
vibrations ν and ν of symmetry e and t , respectively, are
observed in the Raman spectra as depicted in Figure 11. In
the corresponding IR spectra only the vibrations ν > ν are
observed. Thus, the coincidence of each IR band with its
counterpart in the Raman spectrum in the region of the ν
d
symmetry, both totally
1
3
1
2
2
4
2
3
4
3
Figure 11. Comparison of the FIR/MIR (black; 293 K) and Raman spectra
(red; λexc ) 488 nm; ∼15 K) of the [PS4] anions of 2-4.
-1
-1
3-
(
540-609 cm ) and ν
4
vibrations (242-302 cm ) confirms
1
our assignment. The totally symmetric P-S vibration ν in
-
the range 419-444 cm- has the expected very high intensity
1
Raman spectrum of the free [PS
4
]3 anion dissolved in
34
aqueous solution, but most of the vibrational modes in 2-4,
especially ν and ν , are shifted to higher wavenumbers
in the Raman spectrum. It is almost missing in the IR
-
1
1
3
spectrum, while ν at about 207-237 cm is only weak in
2
the Raman and absent in the IR spectrum. The signature of
present Raman spectra follows closely that found in the
(
34) M u¨ ller, A.; Mohan, N.; Cristophliemk, P.; Tossidis, I.; Dr a¨ ger, M.
Spectrochim. Acta 1973, 29A, 1345–1356.
Inorganic Chemistry, Vol. 47, No. 17, 2008 7531

Wu and Bensch
is less disordered and tighter (mean d(Nd-S) ) 2.96 Å) than
that in the closely related potassium salt 2 (mean d(Nd-S
)
3.00 Å). As a consequence of the somewhat different
crystal fields of the two crystallographically independent
Nd ions some of the electronic Raman (ER) lines are
noticeably split and broadened in the FT-Raman spectrum
3
+
3
8
of 4. Because of the nephelauxetic effect the baricenter of
4
3+
the I11/2 manifold of Nd in pure sulfur coordination in
comparison to that in an oxo environment should be at
slightly lower energy, but this cannot fully be confirmed
3
7
considering the data of Xu et al.
The ER effect has been shown to be a powerful tool to
study low lying d-d or f-f transitions as these are allowed
by group theoretical selection rules but are parity forbidden
and hence weak in the absorption spectra. One of the most
prominent examples among others is the ER spectra of the
Figure 12. FT-Raman spectra (λexc ) 1064 nm, 293 K) of 2-4 and
assignment of the electronic Raman transitions from the ground level of
4
4
4
the I9/2 manifold to Stark levels of the I9/2 and I11/2 manifolds, respectively.
intraconfigurational transitions within the spin-orbit split
ground state of low-spin Os in [OsBr ] . But even
6
because of the tighter P-S binding in the solid state. As a
consequence of the presence of two crystallographically
unique phosphorus atoms in 2-4, there is a set of the four
2-
40
4
+
though ER spectroscopy has been studied for more than four
decades now, it has nonetheless never realized the same as
today’s common use of absorption spectroscopy for mainly
three reasons: First the experimentally accessible spectro-
scopic range in common Raman spectrometers is limited to
3-
internal vibrations for each [PS
both ν modes apparently coincide at 426 cm . Furthermore,
every [PS
degenerate modes of the above assuming T
4
]
anion, except for 3, where
-1
1
3
-
4
]
anion has only C
1
symmetry, and hence all
symmetry are
d
-
1
about 8500 cm ; second the discrimination of ER from
vibrational Raman transitions, as for instance in large
molecules like porphyrins or phthalocyanines, is a challenge;
expected to split depending on their degeneracy into two or
three modes of symmetry a, that are IR and Raman active.
The complete lifting of the degeneracy is confirmed pre-
4
1
and last there is a great fortuity to find a selective
dominantly for the ν
of triplets as indicated in Figure 11. Remarkably, the split
components of the ν and ν modes for 3 show a particularly
3
4
and ν modes forming a distinct doublet
resonance enhancement. Although the discrimination of the
ER and vibrational Raman lines is currently of no doubt,
our studies are experimentally limited to a range 100 < ν <
3
4
alternating behavior as bands being intense in the IR
spectrum are weak in the Raman spectrum and vice versa.
Thus, for every of these modes, there is a sequence of strong-
weak-strong absorptions in the IR spectrum and vice versa
for the intensities of the Raman lines that gives strong
evidence for our assignment.
-
1
3
000 cm and therefore only transitions from the ground
level to Stark levels of the ground-state and first excited-
4
2
state are detectable. According to Albrecht’s theory the
6
high intensity enhancement of up to 10 involving only totally
symmetrical transitions by A-term scattering requires the
close approach or coincidence of the excitation laser line
with a strong dipole allowed electronic transition of the
molecule. A much weaker enhancement is observed for the
remaining transitions by B-term scattering when the excita-
tion is between two interacting electronic states. Correspond-
ingly, in the present study a resonant excitation with 1064
The FT-Raman-spectra of 2-4 excited with λexc ) 1064
nm are displayed in Figure 12. Besides the now merely
-
1
detectable symmetrical P-S-vibrations ν
1
at about 430 cm
-1
there are other very strong lines at about 100-250 cm and
950-2250 cm . In agreement with the energy levels of
we attribute the lines with Raman shifts <250
cm to transitions to Stark levels within the manifold of
the electronic Nd ground state I9/2 and those with Raman
shifts within the range 1950-2250 cm to transitions from
-
1
1
Nd
3+
35-37
-
1
4
-
1
nm (∼9400 cm ) via B-term scattering involving the I
13/2
-1 4 -1
3
+
4
(∼6000 cm ) and F (11240 cm ) intermediate states is
3/2
-
1
supposed to be responsible for the significant enhancement
by a factor of about 30 of the ER transition strength as
compared to that of the totally symmetrical P-S stretching
vibration ν1.
the electronic ground-state to the Stark levels of the first
4
excited I11/2 manifold. These transitions are especially well-
-1
resolved in the spectrum of 3 at 176 and 244 cm for those
4
of the I9/2 manifold and at 1983, 2006, 2044, 2116, 2171,
-
1
4
(
(
38) Jørgensen, C. K.; Pappalardo, R.; Flahaut, J. J. Chim. Phys. 1967, 62,
and 2217 cm for the six levels of the I11/2 manifold,
probably because the crystal field in the {NdS } polyhedron
4
44–448.
8
39) Homborg, H. Z. Anorg. Allg. Chem. 1980, 460, 27–36. (b) Clark,
R. J. H.; Stewart, B. Struct. Bonding [Berlin] 1979, 36, 1–80.
(
(
35) Jørgensen, C. K. Orbitals in Atoms and Molecules; Academic Press:
(40) Homborg, H. Z. Anorg. Allg. Chem. 1982, 493, 121–138.
(41) (a) Sievertsen, S.; Schlehhahn, H.; Homborg, H. Z. Naturforsch. 1994,
49B, 50–56. (b) Sievertsen, S.; Schlehhahn, H.; Homborg, H. Z. Anorg.
Allg. Chem. 1993, 619, 1064–1072. (c) Galich, L.; H u¨ ckst a¨ dt, H.;
Homborg, H. J. Porphyrins Phthalocyanines 1997, 1, 259–265. (d)
Sievertsen, S.; Galich, L.; Homborg, H. Z. Naturforsch. 1995, 50A,
881–887.
London and New York, 1962.
36) (a) Dieke, G. H. Spectra and Energy LeVels of Rare Earth Ions in
Crystals; Interscience: New York, 1968. (b) Schulz, H.; Reddmann,
H.; Amberger, H.-D.; Kanellakopulos, B.; Apostolidis, C.; Rebizant,
J.; Edelstein, N. M. J. Organomet. Chem. 2001, 622, 19–32.
37) Xu, Y.-Z.; Wu, J.-G.; Sun, W.-X.; Tao, D.-L.; Yang, L.-M.; Song,
Z.-F.; Weng, S.-F.; Xu, Z.-H.; Soloway, R. D.; Xu, D.-F.; Xu, G.-X.
Chem.sEur. J. 2002, 8, 5323–5331.
(
(42) (a) Albrecht, A. C. J. Chem. Phys. 1961, 34, 1476–1484. (b) Albrecht,
A. C.; Hutley, M. C. J. Chem. Phys. 1971, 55, 4438–4443.
7532 Inorganic Chemistry, Vol. 47, No. 17, 2008

9 4 4 3 4 2 3 4 2 3 3 4 4
K Nd[PS ] , K Nd[PS ] , Cs Nd[PS ] , and K Nd [PS ]
Figure 13. Comparison of the vis/NIR diffuse reflectance spectrum (A:
hatched line; 293 K) and the emission spectra of 3 (B: LABS spectrum;
λexc ) 454.5 nm; ∼15 K; C: luminescence spectrum; 514.5 nm; ∼15 K).
The vis/NIR diffuse reflectance spectrum of 3 measured at
293 K (Figure 13A) displays a number of broad absorptions
that are as well observed in the spectra of 2 and 4 and that are
3+
attributable to the well-known f-f transitions of the Nd ion.
Absorptions that will not be detailed in the following discussion
4
are assigned as follows to electronic transitions from the I9/2
ground state to excited states which are given in parentheses:
4
4
4
4
5
830 ( I15/2), 11240 ( F3/2), 12290 ( F5/2), 13190 ( F7/2), 13340
4
4
2
4
(
S
G
G
3/2), 14520 ( F9/2), 15600 ( H11/2), 16810 ( G5/2), 17010
2
4
4
2
(
(
7/2), 18740 ( G7/2), 19160 ( G9/2), 19440 ( K13/2), 20900
4
11/2), 21470 ( D3/2), 22930 cm ( P1/2). The transition to 4I13/2
2
-1 2
-
1 35
expected to be at about 4000 cm
has neither been detected
in the diffuse reflectance spectra nor in the IR spectra. Optical
band gaps were estimated from the very broad and intense
absorption band extending far into the UV to be at about 3.50
eV for 2, 3.15 eV for 3, and 3.28 eV for 4. These values are
only lower limits because there are still some overlapping f-f
transitions.
Figure 13B,C shows emission spectra obtained by excita-
+
tion of 3 at ∼15 K with the Ar laser line at 454.5 nm (B)
and 514.5 nm (C) together with the corresponding wave-
numbers and assignments. Essentially comparable, but
thoroughly more structured spectra have been observed for
Figure 14. Details of the vis/NIR diffuse reflectance spectrum (hatched
line; 293 K) and the emission spectra of 3 (LABS spectrum; λexc ) 454.5
nm; ∼15 K; luminescence spectrum; 514.5 nm; ∼15 K). For clarity, the
4
2
and 4 that will not be discussed here. The emission
transitions involving the ground state I9/2 are indicated only by the
corresponding excited-state manifolds.
spectrum (Figure 13B) excited at 454.5 nm just above the
2
spin-forbidden D3/2 manifold shows a very broad lumines-
overlaying narrow weak electronic absorption bands pre-
dominantly of the d-d or f-f type, sometimes even permitting
the detection of very weak absorptions that are otherwise
-1
cence with half-bandwidth of ∼4000 cm covering almost
completely the accessible spectral range of the Raman
4
39
spectrometer and maximizing just between the G5/2 and
hidden within the basis of strong charge-transfer bands.
2
3+
H11/2 absorptions. The present study reveals no clear answer
As detailed in Figure 14A-D, the broad Nd absorptions
whether the origin of this luminescence is an intrinsic
of the former diffuse reflectance spectrum have now changed
into finely resolved narrow absorption lines forming mul-
tiplets according to their excited-state manifolds. In addition,
as a consequence of the low temperature hot bands forming
shoulders on the low energy wing of the absorption bands
in the diffuse reflectance spectrum at 293 K are now missing,
for example, for G5/2 in Figure 13C or G7/2 in Figure 14D.
The emission spectrum presented in Figure 13C and
detailed and assigned in Figure 14A-D is obtained by
3
+
property of the Nd ion or simply because of small
impurities present in the sample. Nevertheless, although
broad, the luminescence band is finely structured by a number
of absorptions that without any doubt reproduce the corre-
3
+
sponding Nd absorptions as detailed in Figure 14A-D.
Similar spectra, called according to the phenomenon “lumi-
nescence-absorption” or “LABS” spectra have been observed
4
4
4
0,42
occasionally
when a broad intense luminescence is
Inorganic Chemistry, Vol. 47, No. 17, 2008 7533

Wu and Bensch
3
5,36
and the 4I11/2 manifold
excitation with λexc ) 514.5 nm on the high energy wing of
the spin-allowed G9/2 absorption (Figure 14A). The once
agreement with literature data,
4
agrees well with our diffuse reflectance data between 5840
-
1
broad emission has now turned into a number a very sharp
and partly very intense luminescence lines. Four of them
and 6212 cm .
4
. Conclusions
4
coincide with absorption lines at 18681 ( G7/2), 16692
4
4
-1 4
(
G
5/2), 14489 ( F9/2), and 13186 cm ( F7/2) and are assigned
The successful synthesis of K
9
Nd[PS
4
]
4
(1), K
3 4 2
Nd[PS ]
to the lowest level of the corresponding spin-allowed
(2), Cs
3
Nd[PS
4
]
2
(3), and K
3
Nd
3
[PS (4) is a further step
4 4
]
2
S+1
manifolds. Transitions between
L
J
manifolds with ∆S )
in the direction of a promising chemistry of rare earth
chalcogenophosphates with unusual structural features and
spectroscopic properties. The structures of the title com-
pounds with different motifs reflect the high flexibility of
0
, ∆L ) ( 2 and ∆J ) ( 2 are considered to be
4
“
hypersensitive”. Accordingly, the hypersensitive G5/2
f
4
I
9/2 transition is split into two well separated components
4G′5/2 and G′′5/2; ν ) 42 cm ; Figure 14B), most likely
4
-1
3+
(
both the coordination of Ln cations and the binding modes
3
+
3-
anions. In the present cases, the Ln3+ ions show
because of marginally different Nd ions being present in
the crystal structure. A comparable but smaller splitting of
2
of [PS
4
]
a clear preference for a bicapped trigonal prismatic or trigonal
dodecahedral environment. In our ongoing investigations
about rare earth chalcogen compounds a systematic variation
of the ratios of the educt materials as well as of the heating
conditions should lead to the formation of further new
compounds, shedding light onto the relations between
constituents of the compounds and structural and spectro-
scopic features.
-
1
4
4 cm is also observed for G7/2 that is known to mix
4
35,36
strongly with G5/2
and is therefore to some extent
hypersensitive as well. By far the most intense luminescence
4
is that of G5/2 followed by four very intense to medium
luminescence lines a-e, that are attributed to the Stark levels
4
-1
of the ground manifold I9/2. While d (176 cm ) and e (245
-
1
cm ) correspond to the ER lines in Figure 12, those at 67
a) and 134 cm (b) are supposed to be obscured in the ER
-
1
(
Acknowledgment. The authors thank Ms. I. Jess and Dr.
C. N a¨ ther for single crystal data collections, Ms. U. Corne-
lissen and Dr H. Homborg for measurements and helpful
discussions about vibrational, absorption, luminescense and
electronic Raman Spectra. Funding for this work was
provided by the State of Schleswig-Holstein and the Fonds
der Chemischen Industrie (FCI).
spectrum for experimental reasons. The corresponding transi-
tions of the split component G′′5/2 are very weak but
4
nevertheless detectable as indicated (Figure 14B). The three
most intense lines of these transitions are also observed for
4
4
G′7/2 (Figure 14A) and F7/2 (Figure 14D), thus strongly
confirming our assignment of the ER lines. There is still an
intense luminescence multiplet starting at 14800 cm (Figure
-1
1
1
4C) and another one with much lower intensity (Figure
4
Supporting Information Available: X-ray crystallographic files
(in CIF format) for compound 1, 2, 3, and 4. This information is
available free of charge via the Internet at http://pubs.acs.org.
4A) that are tentatively assigned to the levels of the G7/2
4
4
4
f I13/2, I15/2 transitions, respectively. Consequently, the I13/2
manifold that has not been detected in the diffuse reflectance
and IR spectra is found between 3891 and 4045 cm in
-
1
IC800143X
7534 Inorganic Chemistry, Vol. 47, No. 17, 2008