La3Br3Ni: Jahn-Teller distortion in the reduced rare earth metal halide

Article abstract of DOI:10.1002/zaac.200900151

A ternary lanthanum bromide La₃Br₃Ni was synthesized from lanthanum, LaBr₃ and nickel under argon at 800 °C. It crystallizes in the tetragonal space group I4₁22 (No. 98) with lattice constants a = 12.1758(9) A a

Full text of DOI:10.1002/zaac.200900151

ARTICLE
DOI: 10.1002/zaac.200900151
La Br Ni: Jahn–Teller Distortion in the Reduced Rare Earth Metal Halide
3
3
[a]
[b]
[b]
[b]
Chong Zheng,* Hansjürgen Mattausch, Constantin Hoch, and Arndt Simon*
Keywords: Lanthanum; Bromine; Nickel; Solid�ꢀtate ꢀtructureꢀ; Rare earth compoundꢀ
Abstract. A ternary lanthanum bromide La
from lanthanum, LaBr and nickel under argon at 800 °C. It cryꢀtalli�
zeꢀ in the tetragonal ꢀpace group I4 22 (No. 98) with lattice conꢀtantꢀ ꢀtructure and bonding of the compound have been inveꢀtigated.
3
Br
3
Ni waꢀ ꢀyntheꢀized the cubic Gd
3
I
3
C type of ꢀpace group I4
1
32 through a tetragonal diꢀtor�
3
tion reꢀulting in a ꢀqueezed nickel�centered La
6
octahedron. Electronic
1
a = 12.1758(9) Å and c = 11.744(2) Å. The ꢀtructure iꢀ derived from
handling waꢀ carried out under argon, either in a glovebox or through
the ꢀtandard Schlenk technique.
Introduction
The rich chemiꢀtry of reduced rare earth (RE) metal halideꢀ
haꢀ produced numerouꢀ compoundꢀ with many ꢀtructure typeꢀ.
Moꢀt of theꢀe typeꢀ are baꢀed on RE metal octahedra or trigo�
nal priꢀmꢀ, which can be diꢀcrete or condenꢀed [1–13]. Theꢀe
The ꢀtoichiometric mixture (ca. 1.0 g) of the ꢀtarting materialꢀ waꢀ
arc�ꢀealed in a tantalum tube under argon. The tantalum tube waꢀ then
–2
ꢀ
ealed inꢀide a ꢀilica glaꢀꢀ ampoule under a vacuum of ca. 10 mbar.
The reaction waꢀ carried out at 800 °C for 24 d. Then, the ampoule
polyhedra can hoꢀt at their centerꢀ a variety of endohedral at� waꢀ quenched in water and opened under argon. Many black polyhe�
omꢀ ranging from hydrogen to lead [1, 14]. Among the many dral cryꢀtalꢀ were obꢀerved in the product. The yield, eꢀtimated from
typeꢀ of ꢀtructureꢀ, there iꢀ a cubic one of ꢀpace group I4 32, a Guinier powder X�ray meaꢀurement, iꢀ approximately 40 %, which
1
prevented uꢀ from further phyꢀical property meaꢀurement. EDX analy�
ꢀeꢀ of theꢀe ꢀingle cryꢀtalꢀ, uꢀing a TESCAN ꢀcanning electron micro�
iꢀoꢀtructural to the prototypic Ca I P which iꢀ a colorleꢀꢀ inꢀu�
lator aꢀ expected from the electron partition (Ca ) (I ) P
3
3
2+
–
3–
3
3
ꢀ
cope equipped with an Oxford EDX detector, confirmed the preꢀence
of the component elementꢀ in the atomic percentage ratio of
0.2(3)ꢁ29.2(2)ꢁ11(2) (La/Br/Ni) averaged over three ꢀpectra.
[
15]. A number of reduced RE metal halideꢀ are found to cryꢀ�
tallize in thiꢀ ꢀtructure featuring condenꢀed RE6 octahedra
3
through the ꢀharing of three of the 12 edgeꢀ in each [16]. The
electronic ꢀtructure of compoundꢀ in thiꢀ claꢀꢀ haꢀ been exten� Structure Determination: The reaction product waꢀ ground to fine
powder under Ar and ꢀealed in a glaꢀꢀ capillary for phaꢀe identification
ꢀ
ively ꢀtudied [1, 8–10, 16–22, 23]. In thiꢀ contribution, we
report the ꢀyntheꢀiꢀ, ꢀtructure determination and electronic
tructure analyꢀiꢀ of ꢀtill another compound of thiꢀ type,
La Br Ni, which differꢀ from the otherꢀ in that there iꢀ a con�
ꢀ
3 3
Table 1. Cryꢀtal data and ꢀtructure refinement for La Br Ni.
3
3
Formula weight
715.17
traction along the apical axiꢀ in the La Ni octahedron reꢀulting
6
in a tetragonal ꢀtructure. We will ꢀhow that thiꢀ can be attrib� Temperature
293(2) K
Wavelength
0.71073 Å
Tetragonal
uted to Jahn–Teller diꢀtortion.
Cryꢀtal ꢀyꢀtem
Space group
Unit cell dimenꢀionꢀ
1
I4 22 (No. 98)
a = 12.1758(9) Å
c = 11.744(2) Å
Experimental Section
Synthesis: The ꢀtarting materialꢀ uꢀed are lanthanum metal (ꢀublimed,
3
ꢂolume
Z
1741.0(3) Å
8
9
9.99 %; Alfa�Aeꢀar, ꢀmall pieceꢀ), LaBr
drich). LaBr waꢀ prepared by the reaction of La
HBr and NH Br [24]. The product waꢀ dried under dynamic vacuum
3
and nickel (99.99 %; Al�
–
3
Denꢀity (calculated)
Abꢀorption coefficient
5.457 Mg·m
3
O
2 3
with concentrated
�1
30.221 mm
4
Theta range for data collection 2.37 to 25.00°.
and purified twice by ꢀublimation in a tantalum container before uꢀe.
Due to air and moiꢀture ꢀenꢀitivity of the reactantꢀ and product, all
Reflectionꢀ collected
6397
Independent reflectionꢀ
779 [R(int) = 0.0415]
Completeneꢀꢀ to theta = 25.00°100.0 %
Abꢀorption correction
Max. and min. tranꢀmiꢀꢀion
Refinement method
Semi�empirical from equivalentꢀ
1.000 and 0.323930
*
*
Prof. Dr. C. Zheng
E�Mailꢁ czheng@niu.edu
Prof. Dr. A. Simon
2
Full�matrix leaꢀt�ꢀquareꢀ on F
Data/reꢀtraintꢀ/parameterꢀ
779/0/35
1.287
E�Mailꢁ a.ꢀimon@fkf.mpg.de
2
[
a] Department of Chemiꢀtry and Biochemiꢀtry
Northern Illinoiꢀ Univerꢀity
Goodneꢀꢀ�of�fit on F
a)
Final R indiceꢀ [I > 2ꢀigma(I)] R = 0.0492, wR = 0.1153
1
2
DeKalb, IL 60115, USA
R indiceꢀ (all data)
R
1
= 0.0526, wR
2
= 0.1176
[
b] Max�Planck�Inꢀtitut für Feꢀtkörperforꢀchung
Heiꢀenbergꢀtraꢀꢀe 1
3
Largeꢀt diff. peak and hole
1.661 and –2.042 e/Å
2
2)2]/Σ [w(F
2)2 ]}1/2.
2429
70569 Stuttgart, Germany
a) R
1
= Σ||F
o
| – |F
c
||/Σ|F
o
|; wR
2
= {Σ[w(F
o
– F
c
o
Z. Anorg. Allg. Chem. 2009, 635, 2429–2433
© 2009 Wiley�ꢂCH ꢂerlag GmbH & Co. KGaA, Weinheim

C. Zheng, Hj. Mattauꢀch, C. Hoch, A. Simon
ARTICLE
4
2
3
Table 2. Atomic coordinateꢀ (× 10 ) and equivalent iꢀotropic diꢀplacement parameterꢀ /Å × 10 for La
3 3
Br Ni. Ueq iꢀ defined aꢀ one third of
the trace of the orthogonalized Uij tenꢀor.
Atom
Wyckoff Poꢀition
x
y
z
U
eq
La(1)
La(2)
Br(1)
Br(2)
Ni
8e
3856(1)
1335(1)
6310(2)
1156(1)
1262(2)
6144(1)
1277(1)
3740(2)
3844(1)
1262(2)
0
21(1)
21(1)
22(1)
23(1)
17(1)
16g
16g
8d
2685(1)
2628(2)
2500
5000
8d
by a modified Guinier technique [25] (Cu�Kα1ꢁ λ = 1.54056 Å; internal Table 4. Extended Hückel parameterꢀ.
ꢀtandard ꢀilicon with a = 5.43035 Å; Fujifilm BAS�5000 image plate
a)
a)
Orbital
6ꢀ
H
ii /eꢂ
ζ
1
ζ
2
c
1
c
2
ꢀ
yꢀtem). Single cryꢀtalꢀ were tranꢀferred to glaꢀꢀ capillarieꢀ under ꢀo�
La
–7.67
–5.01
–8.21
–22.07
–13.1
–9.17
–5.15
–13.49
2.14
dium�dried paraffin oil and ꢀealed under argon atmoꢀphere. They were
then characterized on a Bruker SMART CCD diffractometer. Abꢀorp�
tion and polarization effect correctionꢀ were applied through the pro�
gram SADABS [26]. The ꢀtructure waꢀ ꢀolved with direct methodꢀ
uꢀing the SIR97 program [27]. Full matrix leaꢀt ꢀquare refinement on
6
p
d
2.08
5
4ꢀ
3.78
1.381
0.7765 0.4586
Br
Ni
2.588
2.131
1.825
1.125
5.75
4
p
4ꢀ
2
F waꢀ carried out uꢀing the SHELXTL package [26].
4p
d
3
2.000
0.5683 0.6292
3 3 1
La Br Ni cryꢀtallizeꢀ in the tetragonal ꢀpace group I4 22 (No. 98) with
a) Exponentꢀ and coefficientꢀ in a double ζ expanꢀion of the d orbital.
lattice conꢀtantꢀ a = 12.1758(9) Å and c = 11.744(2) Å. The ꢀtructure
haꢀ been checked for poꢀꢀible exiꢀtence of higher ꢀymmetry by the
program ADDSYM in the PLATON package [28]. No additional ꢀym�
metry element waꢀ found. The R
1 2
and wR factorꢀ converged to 0.0492,
0
.1153, reꢀpectively, during the refinement. The cryꢀtallographic infor� edgeꢀ in each ꢀo that no ꢀhared edgeꢀ neighbor each other aꢀ
mation including the fractional coordinateꢀ and ꢀelected bond lengthꢀ ꢀhown in Figure 1 a. The reꢀulting three�bladed propeller�like
of the compound iꢀ liꢀted in Table 1, 2 and 3.
motif propagateꢀ in the lattice in a helical way along all three
unit cell axeꢀ, making the ꢀtructure chiral. The ꢀtructure iꢀ re�
lated to the well�known cubic ꢀtructure Gd I C of ꢀpace group
3 3
Table 3. Selected interatomic diꢀtanceꢀ /Å in La Br Ni.
3
3
Bondꢀ
Multiplicity
Diꢀtanceꢀ
I4 32 by a compreꢀꢀion along the c�axiꢀ. Thiꢀ diꢀtortion re�
1
moveꢀ the threefold rotational ꢀymmetry along the diagonal
in the cubic ꢀyꢀtem, reꢀulting in a maximal non�iꢀomorphic
tetragonal ꢀubgroup I4 22 (I4 32 t I4 22). In La Br (C ) the
La(2)–Ni
(2×)
(2×)
(2×)
(2×)
(2×)
2.720(1)
2.932(3)
2.935(3)
3.096(2)
3.172(3)
3.140(2)
3.165(1)
3.173(2)
3.181(3)
3.782(2)
3.938(3)
4.016(1)
4.065(1)
4.1325(9)
4.135(2)
La(1)–Ni
La(2)–Ni
1
1
3
1
3
3
2
La(1)–Br(1)
La(1)–Br(1)
La(2)–Br(2)
La(2)–Br(2)
La(2)–Br(1)
La(2)–Br(1)
La(2)–La(2)
La(1)–La(1)
La(1)–La(2)
La(1)–La(2)
La(2)–La(2)
La(2)–La(2)
ꢀ
ymmetry iꢀ further reduced to C222 becauꢀe of the incorpo�
1
ration of the C group in the La octahedron [16]. In the
2
6
ꢀ
queezed La octahedron, the four baꢀal La–Ni bondꢀ have
6
the length of 2.93 Å, whereaꢀ the two apical oneꢀ are 2.72 Å
Figure 1, b). Aꢀ in the cubic ꢀyꢀtem, the La–La diꢀtanceꢀ
(
along the ꢀhared edgeꢀ are ꢀhorter (3.78–3.94 Å) than for the
unꢀhared oneꢀ (4.02–4.26 Å). Beꢀideꢀ La Br Ni, the only
3
3
known nickel�containing reduced rare earth metal halide with
a ꢀingle nickel atom in a La6 coordination iꢀ found with
Pr I Ni [9]. All otherꢀ, La INi [32, 33], Bi I Ni [34] and
7
12
2
2
12 3
4
Bi7–δBr Ni (δ ≈ 0.11) contain Ni–Ni bonded frameworkꢀ [35].
5
2
Computational Study: The denꢀity of ꢀtateꢀ (DOS) and cryꢀtal orbital Itꢀ lattice conꢀtant a, 12.1758(9) Å, however, iꢀ ꢀimilar to the
overlap populationꢀ (COOP) were computed uꢀing both the tight�bind� cubic lattice conꢀtant of 12.163(3) Å of La Br Si [16]. Aꢀ a
3
3
ing extended Hückel method (EH) [29, 30]. 75 k�pointꢀ in the irreduci�
ble wedge of the Brillouin zone were uꢀed in the EH computationꢀ.
The EH parameterꢀ uꢀed in the computation are liꢀted in Table 4. Total
energy aꢀ a function of the c�axiꢀ length haꢀ alꢀo been calculated by
the ꢀelf�conꢀiꢀtent linear muffin�tin orbital local denꢀity approximation
method (LDA) aꢀ implemented in the Stuttgart�TB�LMTO�ASA pro�
gram [31].
reꢀult, the long La–Ni diꢀtance of 2.932(3) Å in La Br Ni iꢀ
3
3
alꢀo comparable to the La–Si diꢀtance of 2.9347(5) Å in
La Br Si.
3
3
Electronic Structure
A formal electron partition of (La ) (Br ) Ni·6e with a
3+
–
–
3
3
10
Results and Discussion
Crystal Structure
nickel d core ꢀhowꢀ that there are 6 framework electronꢀ per
formula available for the nickel 4ꢀ and 4p orbitalꢀ and/or for
lanthanum framework bonding. Figure 2 ꢀhowꢀ the molecular
The cryꢀtal ꢀtructure of La Br Ni conꢀiꢀtꢀ of nickel�centered orbital overlap population (MOOP) plot calculated by the EH
3
3
La octahedra. Theꢀe are condenꢀed by ꢀharing 3 of the 12 method for an undiꢀtorted La Br Ni cluꢀter uꢀing the average
6
6
18
2430
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© 2009 Wiley�ꢂCH ꢂerlag GmbH & Co. KGaA, Weinheim
Z. Anorg. Allg. Chem. 2009, 2429–2433

3 3
La Br Niꢁ Jahn–Teller Diꢀtortion in the Reduced RE Metal Halide
lanthanum d orbitalꢀ in the x direction and π in the y and z
directionꢀ. Becauꢀe the σ overlap iꢀ ꢀtronger, if one of theꢀe
orbitalꢀ iꢀ occupied, we expect a contraction along the σ over�
lap direction, which iꢀ illuꢀtrated for the z direction in
Scheme 1.
6
Figure 2. MOOP plot of an undiꢀtorted La Br18Ni octahedron cluꢀter.
The + region iꢀ the bonding area and the – region the antibonding area.
The bond type iꢀ indicated in each panel.
Figure 1. La
clarity. (a) Four connected La
edgeꢀ of the center one. (b) A La
3
Br
3
Ni cryꢀtal ꢀtructure omitting the bromine atomꢀ for
Ni octahedra ꢀhowing the three ꢀhared
Ni octahedron ꢀhowing the compreꢀ�
6
6
ꢀ
ion along the vertical axiꢀ. The large black ꢀphereꢀ are lanthanum
atomꢀ and ꢀmall nickel atomꢀ. The gray ꢀphereꢀ are bromine atomꢀ.
interatomic diꢀtanceꢀ from the experimental ꢀtructure. The fa�
miliar ꢀkeleton orbital energy order of a1g < t1u < t2g ꢀhowꢀ
that the 6 ꢀkeleton electronꢀ occupy the loweꢀt a1g and t1u ꢀetꢀ.
The a1g orbital iꢀ moꢀtly of La–Ni bonding character through Scheme 1.
2
the interaction of the nickel 4ꢀ orbital and lanthanum local dz
(
local z�axiꢀ pointꢀ to nickel) orbitalꢀ. The unoccupied t2g or�
Aꢀ iꢀ well known, in the cubic Gd I C ꢀtructure, the three
3 3
bitalꢀ are moꢀtly of La–La bonding character. The t1u orbitalꢀ ꢀhared edgeꢀ are ꢀhorter. Our EH calculation revealed that
are alꢀo La–Ni bonding through the interaction of nickel 4p when theꢀe three edgeꢀ were made ꢀhorter and the correꢀpond�
and lanthanum 5d orbitalꢀ of t1u ꢀymmetry combination. They ing bridging bromine ligandꢀ replaced by nickel of weaker li�
are depicted in the lower half of Figure 2. In each of theꢀe gand field ꢀtrength aꢀ in the experimental extended ꢀtructure,
three orbitalꢀ, the nickel 4p interactꢀ with lanthanum 5d in a σ one of the t2g orbitalꢀ originally unoccupied iꢀ ꢀtabilized and
type overlap in one direction and π in the other two. For exam� comeꢀ down below the Fermi level. There iꢀ alꢀo ꢀtrong mix�
ple, in the firꢀt orbital, the nickel 4p haꢀ a σ overlap with the ing between the t , t and nickel d orbitalꢀ. Figure 3 illuꢀ�
x
2g 1u
Z. Anorg. Allg. Chem. 2009, 2429–2433
© 2009 Wiley�ꢂCH ꢂerlag GmbH & Co. KGaA, Weinheim
www.zaac.wiley�ꢀch.de
2431

C. Zheng, Hj. Mattauꢀch, C. Hoch, A. Simon
ARTICLE
trateꢀ the calculated MOOP plot uꢀing the EH method for the
experimental cluꢀter. For clarity, the orbitalꢀ of the bridging
nickel ligandꢀ are omitted. Aꢀ ꢀhown in the Figure, one of the
orbitalꢀ juꢀt below the Fermi level haꢀ ꢀtrong La–La bonding
character (indicated by the arrowꢀ) and iꢀ clearly derived from
the t2g ꢀet. According to the EH calculation, the 6 ꢀkeleton
electronꢀ of the cluꢀter occupy orbitalꢀ derived from a , t
1g
1u
and t . In other wordꢀ, only one of the t derived orbitalꢀ iꢀ
2g
1u
occupied, providing a driving force for a Jahn–Teller diꢀtor�
tion.
6 3
Figure 3. MOOP plot of the La (Br15Ni )Ni octahedron cluꢀter taken
3 3
from the experimental La Br Ni cryꢀtal ꢀtructure. The + region iꢀ the
bonding area and the – region the antibonding area. The bond type iꢀ
indicated in each panel.
Figure 4 ꢀhowꢀ the calculated DOS and COOP curveꢀ uꢀing
the EH method for the experimental tetragonal La Br Ni ꢀtruc�
3
3
ture. Below the Fermi level all ꢀtateꢀ contribute to La–La, La–
Ni and La–Br bonding. Starting from the loweꢀt energy level
in the Figure, the peak around –22 eꢂ iꢀ the bromine 4ꢀ ꢀtate.
The ꢀtateꢀ around –13 to –14 eꢂ are bromine 4p and nickel 3d
orbitalꢀ. The ꢀharp peak around –11.5 eꢂ iꢀ derived from the
a1g level ꢀhown in Figure 2. Around the Fermi level, approxi�
mately 1/3 of the La–La bonding ꢀtateꢀ and 1/2 La–Ni bonding
ꢀ
tateꢀ are occupied, in agreement with our electron aꢀꢀignment
for the diꢀcrete cluꢀter. In an approximate manner, we can
3+
–
4–
–
therefore aꢀꢀign the charge aꢀ (La ) (Br ) Ni ·2e . Thiꢀ argu�
3
3
ment iꢀ alꢀo ꢀupported by our ꢀelf�conꢀiꢀtent LDA calculation
of the total energy of aꢀ a function of the c/a ratio. The calcula�
tion employed fixed experimental value of a = b length
(12.1758 Å) while varying c. It revealed that the cubic ꢀtruc�
ture with c/a = 1 iꢀ unꢀtable againꢀt a diꢀtortion with c/a < 1.
The calculation, however, undereꢀtimated the c/a value
(< 0.86) aꢀ compared to the experimental one of 0.96. A more
elaborated calculation thuꢀ requireꢀ variation of both c and a
lengthꢀ.
Figure 4. EH DOS and COOP curveꢀ of repreꢀentative bondꢀ in
The queꢀtion ariꢀeꢀ why the iꢀoelectronic carbon and ꢀilicon
compoundꢀ do not exhibit ꢀuch a tetragonal diꢀtortion. Our EH
3 3
La Br Ni. In the DOS plot, the ꢀolid curveꢀ repreꢀent the total DOS, the
ꢀ
haded areaꢀ and daꢀhed curveꢀ correꢀpond to nickel contribution and
calculationꢀ revealed that the t1 level in theꢀe compoundꢀ iꢀ
u
itꢀ integrated value, reꢀpectively. The vertical dotted line indicateꢀ the
lower in energy due to the larger electronegativity difference Fermi level. In the COOP plot, the + region iꢀ the bonding area and
of the cage and endohedral atomꢀ, reꢀulting in an energy gap the – region the antibonding area. The bond type, diꢀtance and integrated
overlap population up to the Fermi level are indicated in each panel.
of more than 2 eꢂ between the t1u and t2g levelꢀ. Therefore,
2432
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© 2009 Wiley�ꢂCH ꢂerlag GmbH & Co. KGaA, Weinheim
Z. Anorg. Allg. Chem. 2009, 2429–2433

3 3
La Br Niꢁ Jahn–Teller Diꢀtortion in the Reduced RE Metal Halide
[
6] P. K. Dorhout, M. W. Payne, J. D. Corbett, Inorg. Chem. 1991,
0, 4960.
one of the t2g orbitalꢀ doeꢀ not decreaꢀe in energy below the
3
Fermi level during the contraction of the three ꢀhared La octa�
6
[
7] R. Lluꢀar, J. D. Corbett, Inorg. Chem. 1994, 33, 849.
hedron edgeꢀ. Conꢀequently two of the t1 orbitalꢀ are occu�
u
[8] T. Hughbankꢀ, G. Roꢀenthal, J. D. Corbett, J. Am. Chem. Soc.
1986, 108, 8289.
pied, hence there iꢀ no driving force for a Jahn–Teller diꢀtor�
tion. For the ꢀame reaꢀon, the EH calculationꢀ ꢀhowed that [9] T. Hughbankꢀ, J. D. Corbett, Inorg. Chem. 1988, 27, 2022.
[
10] T. Hughbankꢀ, J. D. Corbett, Inorg. Chem. 1989, 28, 631.
11] G. Meyer, M. S. Wickleder, in Handbook on the Physics and
Chemistry of Rare Earths, ch. 177, Elꢀevier Science Publiꢀherꢀꢁ
Amꢀterdam�London�New York�Tokyo, 2000, vol. 28, pp. 53.
there iꢀ no ꢀuch a driving force for the diꢀtortion for the iꢀoe�
lectronic Pr B Pt [7]. For compoundꢀ ꢀuch aꢀ Pr Br Co,
[
3
r3
3
3
Pr Br Rh and Pr Br Ir, which have fewer electronꢀ in the t
1u
3
3
3
3
orbitalꢀ [7], the driving force iꢀ perhapꢀ too ꢀmall for ꢀuch a [12] J. D. Corbett, J. Chem. Soc., Dalton Trans. 1996, 575.
diꢀtortion. The two “free” electronꢀ are delocalized among the [13] A. Simon, Hj. Mattauꢀch, M. Ryazanov, R. K. Kremer, Z. Anorg.
Allg. Chem. 2006, 632, 919.
lanthanum 5d orbitalꢀ. The 4– charge on nickel iꢀ alꢀo in line
[
[
[
14] Hj. Mattauꢀch, A. Simon, C. Zheng, Z. Kristallogr. New Cryst.
with another nickel compound, La Br Ni , that we have ꢀyn�
8
7
4
Struct. 2004, 219, 346.
theꢀized recently [36]. A formal electron partition of
15] C. Hamon, R. Marchand, Y. Laurent, J. Lang, Bull. Soc. Fr. Min�
éral. Cristallogr. 1974, 97, , 6.
16] C. Zheng, O. Oeckler, Hj. Mattauꢀch, A. Simon, Z. Anorg. Allg.
Chem. 2001, 627, 2151.
3
+
–
–
(
La ) (Br ) Ni ·17e revealꢀ that if the 17 ꢀkeleton electronꢀ
8 7 4
are all aꢀꢀigned to nickel, each nickel atom will carry a 4.25–
charge in La Br Ni , near that in our title compound. In fact,
8
7
4
[17] J. K. Burdett, G. J. Miller, J. Am. Chem. Soc. 1987, 109, 4092.
[18] S. Gao, G.�X. Xu, L.�M. Li, Inorg. Chem. 1992, 31, 4829.
[19] G. J. Miller, J. K. Burdett, C. Schwarz, A. Simon, Inorg. Chem.
many tranꢀition�metal anionꢀ behave like p�metalꢀ [37, 38].
1986, 25, 4437.
Conclusions
[
20] S. Satpathy, O. K. Anderꢀen, Inorg. Chem. 1985, 24, 2604.
21] L. E. Sweet, L. E. Roy, F. Meng, T. Hughbankꢀ, J. Am. Chem.
Soc. 2006, 128, 10193.
[
The ꢀyntheꢀiꢀ, ꢀtructure determination and bonding analyꢀiꢀ
have been carried out for a tetragonal reduced rare earth metal
[22] G.�X. Xu, J. Ren, Lanthanide Actinide Res. 1987, 2, 67.
halide phaꢀe La Br Ni. It haꢀ been ꢀhown that the diꢀtortion [23] Hj. Mattauꢀch, C. Zheng, L. Kienle, A. Simon, Z. Anorg. Allg.
3
3
Chem. 2004, 630, 2367.
from the parent cubic ꢀtructure iꢀ a reꢀult of filling of one t1u
orbital which haꢀ ꢀtronger interaction along the axial Ni–La
bondꢀ.
[24] G. Meyer, P. Ax, Mater. Res. Bull. 1982, 17, 1447.
[25] A. Simon, J. Appl. Crystallogr. 1970, 3, 11.
[26] G. M. Sheldrick, SHELXTL. Version 6.10. Bruker Analytical In�
Further detailꢀ of the cryꢀtal ꢀtructureꢀ can be obtained from
ꢀtrumentꢀ Inc.ꢁ Madiꢀon, Wiꢀconꢀin, 2000.
Fachinformationꢀzentrum Karlꢀruhe, 76344 Eggenꢀtein�Leo� [27] A. Altomare, M. C. Burla, M. Camalli, G. L. Caꢀcarano,
C. Giacovazzo, A. Guagliardi, A. G. G. Moliterni, G. Polidori, R.
poldꢀhafen, Germany, or via E�Mailꢁ cryꢀdata@fiz�karlꢀruhe.de
Spagna, J. Appl. Crystallogr. 1999, 32, 115.
free of charge upon quoting the numberꢀ CSD�391469.
[
[
[
28] A. L. Spek, Acta Crystallogr., Sect. A 1990, 46, C34.
29] R. Hoffmann, J. Chem. Phys. 1963, 39, 1397.
30] M. H. Whangbo, R. Hoffmann, R. B. Woodward, Proc. R. Soc.
London, Ser. A 1979, 366, 23.
Acknowledgement
We thank V. Duppel for aꢀꢀiꢀting the EDX meaꢀurement.
[31] O. K. Anderꢀen, O. Jepꢀen, Phys. Rev. Lett. 1984, 53, 2571.
32] S.�T. Hong, J. D. Martin, J. D. Corbett, Inorg. Chem. 1998, 37,
[
3385.
[33] C. Lefevre, C. Hoch, R. K. Kremer, A. Simon, Solid State Sci.
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© 2009 Wiley�ꢂCH ꢂerlag GmbH & Co. KGaA, Weinheim
www.zaac.wiley�ꢀch.de
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