Z. Kristallogr. NCS 228 (2013) 299-300 / DOI 10.1524/ncrs.2013.0168
299
© by Oldenbourg Wissenschaftsverlag, München
Crystal structure of cadmium iridium, Cd41Ir8
Xian-Juan FengI, II, III, Ding-Bang XiongIV, Yurii Prots*, II, Walter SchnelleII, Jing-Tai ZhaoI and Yuri GrinII
I
Shanghai Institute of Ceramics, Chinese Academy of Science, Dingxi Rd. 1295, Shanghai 200050, P. R. China; *Partner Group of MPGCPfS-SICCAS
Max-Planck-Institut für Chemische Physik fester Stoffe, Nöthnitzer Str. 40, D-01187 Dresden, Germany
III
University of Chinese Academy of Science, Beijing 100080, P. R. China
IV
Philipps University Marburg, Hans-Meerwein-Straße, D-35032 Marburg, Germany
II
Received March 21, 2013, accepted June 17, 2013, available online June 28, 2013, CSD no. 710089
crucible jacked within closed quartz tube and then annealed at
600 °C for a week followed by slow cooling down to room temperature. The X-ray diffraction experiment was performed on
single crystal isolated from an ingot. The lattice parameters was
established from X-ray powder diffraction data (Huber Gunier
G670, CuKa1 radiation) by using LaB6 as internal standard (a =
4.15692 Å). Hot pressing at high frequency furnace (300 °C,
1 hour) was introduced to prepare cuboid-shaped bar for physical
properties measurement. Electrical conductivity and magnetic
susceptibility (SQUID, MPMS XL-5, 2-400 K) were measured
within the Cd41Ir8 bar.
Table 1. Data collection and handling.
Crystal:
Wavelength:
m:
Diffractometer, scan mode:
2qmax:
N(hkl)measured, N(hkl)unique:
Criterion for Iobs, N(hkl)gt:
N(param)refined:
Programs:
Abstract
Cd41Ir8, trigonal, R3 (no. 148), a = 14.8489(6) Å,
c = 15.980(1) Å, V = 3051.4(4) Å3, Z = 3, Rgt(F) = 0.037,
wRref(F2) = 0.067, T = 293 K.
Source of material
The title compound was synthesized from pure elements: Ir
(Chempur 99.9 %) and Cd (Alfa Aesar 99.99 %) powders. The
initial mixture of stoichiometric Cd and Ir was pressed into a pellet (Æ 8 mm) and heated at 1000 °C in a capped glassy graphite
_____________
* Correspondence author (e-mail: [email protected])
grey metallic, irregular shape,
size 0.020´0.025´0.040 mm
Mo Ka radiation (0.71073 Å)
469.2 cm-1
Rigaku AFC7, CCD, oscillation
65.86°
10276, 2561
Iobs > 2 s(Iobs), 2387
77
SHELX [3], WinCSD [4]
Discussion
Cd41Ir8 is the first binary phase synthesized in the Cd-Ir system.
The crystal structure adopts the Ga41V8 structure type [1] (Figure,
top). Iridium and cadmium atoms are located in 2 and 9 independent crystallographic sites, respectively. Each Ir atom is surrounded by 10 Cd neighbours with Cd–Ir distances from 2.683 Å
to 3.113 Å. The [IrCd10] polyhedron formed by Ir2 is more symmetric than the one by Ir1, since it has a three-fold axis passing
through its center. But they are topologically equivalent and the
two neighbored [IrCd10] share one vertex. The coordination
spheres of most cadmium atoms consists of 2 Ir atoms and between 6 and 10 Cd atoms. Solely, Cd2 has a cuboctahedral coordination formed exclusively by Cd neighbours with Cd–Cd
distances between 3.113 Å and 3.127 Å and without any contacts
to Ir atoms. These values agree very well with an average distance
of 3.136 Å observed in elemental cadmium [2]. The [Cd2Cd12]
cuboctahedron shares all its 8 triangular faces with polyhedra
formed around Ir atoms, among which 2 triangular faces on the
top and bottom of cuboctahedron are shared with [Ir2Cd10] and
the other 6 with [Ir1Cd10] (Figure, bottom). There are no Ir–Ir
contacts in the Cd41Ir8 structure. The structure can be described
by packing of coordination polyhedral around both Ir and Cd2 atoms. The investigated phase is stable up to a temperature of
500 °C and decomposes completely around 700 °C. Bulk Cd41Ir8
presents a metal-like behavior in electrical conductivity and is
d i a ma g n e t i c w i t h a n e x t r a p o l a t e d s u s c e pt i b i l t y o f
c0 = 826·10–6 emu/mol.
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Cd41Ir8
300
Table 2. Atomic coordinates and displacement parameters (in Å2).
Atom
Site
x
y
z
U11
U22
U33
U12
Ir(1)
Ir(2)
Cd(1)
Cd(2)
Cd(3)
Cd(4)
Cd(5)
Cd(6)
Cd(7)
Cd(8)
Cd(9)
18f
6c
3a
3b
9e
18f
18f
18f
18f
18f
18f
0.70871(2)
0
0
0
y
0.69386(5)
0.68001(5)
0.53572(4)
0.75840(5)
0.66427(5)
0.88506(5)
0.01975(2)
0
0
0
0
0.01062(5)
0.18049(5)
0.02027(5)
0.89205(4)
0.51700(5)
0.00878(5)
0.40262(2)
0.19481(3)
0
y
0
0.23284(4)
0.45000(4)
0.33767(4)
0.50261(4)
0.55119(4)
0.33894(4)
0.0084(1)
0.0078(1)
0.0222(5)
0.0172(4)
0.0164(4)
0.0197(3)
0.0203(3)
0.0110(3)
0.0179(3)
0.0195(3)
0.0131(3)
0.0076(1)
0.0078(1)
0.0222(5)
0.0172(4)
0.0194(4)
0.0186(3)
0.0134(3)
0.0192(3)
0.0129(3)
0.0116(3)
0.0155(3)
0.0077(1)
0.0128(2)
0.0231(8)
0.0189(8)
0.0150(4)
0.0084(3)
0.0184(3)
0.0164(3)
0.0141(3)
0.0184(3)
0.0174(3)
0.0038(1)
0.00389(7)
0.0111(2)
0.0086(2)
0.0130(3)
0.0107(2)
0.0106(2)
0.0081(2)
0.0087(2)
0.0098(2)
0.0076(2)
Acknowledgments. The authors are indebted to Dr. H. Borrmann and
S. Hückmann for X-ray powder diffraction measurements. We acknowledge
S. Scharsach for thermal analysis.
References
1. Girgis, K.; Petter, W.; Pupp, G.: Crystal-Structure of V8Ga41. Acta
Crystallogr. B31 (1975) 113-116.
U13
-0.0001(1)
0
0
0
-0.0028(3)
-0.0019(2)
-0.0007(2)
-0.0035(2)
0.0001(2)
0.0010(2)
0.0028(2)
U23
-0.00034(9)
0
0
0
-0.0006(3)
-0.0013(2)
-0.0043(2)
-0.0007(2)
0.0029(2)
-0.0010(2)
0.0001(2)
2. Emsley, J.: The elements, 3rd ed. Clarendon Press, Oxford 1999.
3. Sheldrick, G. M.: A short history of SHELX. Acta Crystallogr. A64
(2008) 112-122.
4. Akselrud, L. G.; Zavalii, P. Yu.; Grin, Yu.; Pecharsky, V. K.;
Baumgartner, B.; Wölfel, E.: Use of the CSD program package for structure determination from powder diffraction data. Mater. Sci. Forum 133136 (1993) 335-340.
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