The pyrochlore-type molybdate Pr1.37Ca0.63Mo2O7

Gall, P.; Gougeon, P.

doi:10.1107/S1600536808015328

inorganic compounds

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Volume 64| Part 6| June 2008| Page i42

doi:10.1107/S1600536808015328

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The pyrochlore-type molybdate Pr_1.37Ca_0.63Mo₂O₇

P. Gall ^a and P. Gougeon ^a ^*

^aUnité Sciences Chimiques de Rennes, UMR CNRS No. 6226, Université de Rennes I–INSA Rennes, Campus de Beaulieu, 35042 Rennes CEDEX, France
^*Correspondence e-mail: patrick.gougeon@univ-rennes1.fr

(Received 2 April 2008; accepted 21 May 2008; online 24 May 2008)

Praseodymium calcium dimolybdenum heptaoxide, Pr_1.37Ca_0.63Mo₂O₇, crystallizes in the cubic pyrochlore-type structure. In the crystal structure, MoO₆ octahedra are linked together by common corners, forming a three-dimensional [Mo₂O₆] network. The Pr and Ca atoms and the remaining O atoms are located in the voids of the [Mo₂O₆] network. The Pr and Ca atoms are distributed statistically over the same 16c crystallographic position with site-occupancy factors of 0.684 (3) and 0.316 (3), respectively. They are surrounded by eight O atoms forming a ditrigonal scalenohedron. All atoms lie on special positions. The (Pr, Ca) and Mo atoms are, respectively in the 16c and 16d positions with $[\overline{3}]$ m symmetry, and the O atoms in the 48f or 8a positions with mm or $[\overline{4}]$ 3m site symmetry, respectively.

Related literature

For related literature, see: Hubert (1974 ); Subramanian et al. (1983 ); American Chemical Society (2007 ); Gougeon et al. (2003 ); Kerihuel & Gougeon (1995 ).

Experimental

Crystal data

Pr_1.37Ca_0.63Mo₂O₇
M_r = 522.18
Cubic, $[F d \overline 3m ]$
a = 10.4329 (3) Å
V = 1135.57 (6) Å³
Z = 8
Mo Kα radiation
μ = 16.45 mm⁻¹
T = 293 (2) K
0.16 × 0.14 × 0.12 mm

Data collection

Nonius KappaCCD diffractometer
Absorption correction: analytical (de Meulenaer & Tompa, 1965 ) T_min = 0.093, T_max = 0.125
771 measured reflections
266 independent reflections
167 reflections with I > 2σ(I)
R_int = 0.053

Refinement

R[F² > 2σ(F²)] = 0.027
wR(F²) = 0.086
S = 1.11
266 reflections
12 parameters
Δρ_max = 2.51 e Å⁻³
Δρ_min = −1.55 e Å⁻³

Data collection: COLLECT (Nonius, 1998 ); cell refinement: COLLECT; data reduction: EVALCCD (Duisenberg et al., 2003 ); program(s) used to solve structure: SIR97 (Altomare et al., 1999 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ); molecular graphics: DIAMOND (Brandenburg, 2001 ); software used to prepare material for publication: SHELXL97.

Supporting information

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536808015328/pk2092sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536808015328/pk2092Isup2.hkl

checkCIF report

Comment top

An attempt to synthesize PrCaMo₁₆O₂₈, a compound with the PrMo₈O₁₄ type structure (Kerihuel & Gougeon, 1995), was unsuccessful, resulting in a multiphase product. However, the formation of the new compound, Pr_1.37Ca_0.63Mo₂O₇ was achieved. A survey of the literature related to the rare earth molybdates R₂Mo₂O₇ with the database SciFinder Scholar (American Chemical Society, 2007) shows that these compounds only form for the rare-earths from Nd to Lu. To our knowledge, no quaternary molybdate pyrochlore has thus far been reported.

Related literature top

For related literature, see: Hubert (1974); Subramanian et al. (1983); American Chemical Society (2007); Gougeon et al. (2003); Kerihuel & Gougeon (1995).

Experimental top

Single crystals of Pr_1.37Ca_0.63Mo₂O₇ were prepared from a mixture of Pr₆O₁₁ (Rhone Poulenc, 99.99%), CaMoO₄, MoO₃ (Cerac, 99.95%) and Mo (Plansee, 99.9999%) with the nominal composition PrCaMo₁₆O₂₈. Before use, Mo powder was reduced under a flow of H₂ gas at 1273 K for ten hours in order to eliminate any trace of oxygen. CaMoO₄ was prepared by heating a stoichiometric mixture of CaCO₃ and MoO₃ in an open porcelain crucible at 1073 K for 24 h. The initial mixture (ca 5 g) was cold pressed and loaded into a molybdenum crucible, which was sealed under a low argon pressure using an arc welding system. The charge was heated at a rate of 300 K/h up to 2223 K, and the temperature was held for 5 min., then cooled at 100 K/h to 1373 K and finally furnace cooled. The final product was multiphasic with Pr_1.37Ca_0.63Mo₂O₇ and Pr_{1 -}_xCa_xMo₁₀O₁₆, isomorphous with the RMo₅O₈ compounds (R = La to Gd; Gougeon et al., 2003), as predominant phases. The crystals thus obtained were of irregular shape.

Computing details top

Data collection: COLLECT (Nonius, 1998); cell refinement: COLLECT (Nonius, 1998); data reduction: EVALCCD (Duisenberg et al., 2003); program(s) used to solve structure: SIR97 (Altomare et al., 1999); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg, 2001); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures top

Fig. 1. : View of Pr_1.37Ca_0.63Mo₂O₇ along the [110] direction. Displacement ellipsoids are drawn at the 97% probability level.

Praseodymium calcium dimolybdenum heptaoxide top

Crystal data top

Pr_1.37Ca_0.63Mo₂O₇	D_x = 6.109 Mg m⁻³
M_r = 522.18	Mo Kα radiation, λ = 0.71070 Å
Cubic, Fd3m	Cell parameters from 1172 reflections
Hall symbol: -F 4vw 2vw	θ = 3.4–45.3°
a = 10.4329 (3) Å	µ = 16.45 mm⁻¹
V = 1135.57 (6) Å³	T = 293 K
Z = 8	Irregular block, black
F(000) = 1867.4	0.16 × 0.14 × 0.12 mm

Data collection top

Nonius KappaCCD diffractometer	266 independent reflections
Radiation source: fine-focus sealed tube	167 reflections with I > 2σ(I)
Horizontally mounted graphite crystal monochromator	R_int = 0.053
Detector resolution: 9 pixels mm^-1	θ_max = 45.3°, θ_min = 3.4°
ϕ scans (κ = 0) + additional ω scans	h = 1→20
Absorption correction: analytical (de Meulenaer & Tompa, 1965)	k = 0→14
T_min = 0.093, T_max = 0.125	l = 0→13
771 measured reflections

Refinement top

Refinement on F²	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F² > 2σ(F²)] = 0.027	w = 1/[σ²(F_o²) + (0.0207P)² + 4.885P] where P = (F_o² + 2F_c²)/3
wR(F²) = 0.086	(Δ/σ)_max < 0.001
S = 1.12	Δρ_max = 2.51 e Å⁻³
266 reflections	Δρ_min = −1.55 e Å⁻³
12 parameters	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc^*=kFc[1+0.001xFc²λ³/sin(2θ)]^-1/4
0 restraints	Extinction coefficient: 0.00256 (19)

Crystal data top

Pr_1.37Ca_0.63Mo₂O₇	Z = 8
M_r = 522.18	Mo Kα radiation
Cubic, Fd3m	µ = 16.45 mm⁻¹
a = 10.4329 (3) Å	T = 293 K
V = 1135.57 (6) Å³	0.16 × 0.14 × 0.12 mm

Data collection top

Nonius KappaCCD diffractometer	266 independent reflections
Absorption correction: analytical (de Meulenaer & Tompa, 1965)	167 reflections with I > 2σ(I)
T_min = 0.093, T_max = 0.125	R_int = 0.053
771 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.027	12 parameters
wR(F²) = 0.086	0 restraints
S = 1.12	Δρ_max = 2.51 e Å⁻³
266 reflections	Δρ_min = −1.55 e Å⁻³

Special details top

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement of F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > σ(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq	Occ. (<1)
Pr1	0.0000	0.0000	0.0000	0.00947 (18)	0.685 (3)
Ca1	0.0000	0.0000	0.0000	0.00947 (18)	0.315 (3)
Mo1	0.5000	0.5000	0.5000	0.00539 (19)
O1	0.4247 (3)	0.1250	0.1250	0.0160 (5)
O2	0.1250	0.1250	0.1250	0.0100 (8)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Pr1	0.00947 (18)	0.00947 (18)	0.00947 (18)	−0.00154 (5)	−0.00154 (5)	−0.00154 (5)
Ca1	0.00947 (18)	0.00947 (18)	0.00947 (18)	−0.00154 (5)	−0.00154 (5)	−0.00154 (5)
Mo1	0.00539 (19)	0.00539 (19)	0.00539 (19)	−0.00013 (5)	−0.00013 (5)	−0.00013 (5)
O1	0.0239 (14)	0.0120 (6)	0.0120 (6)	0.000	0.000	−0.0026 (8)
O2	0.0100 (8)	0.0100 (8)	0.0100 (8)	0.000	0.000	0.000

Geometric parameters (Å, º) top

Pr1—O2ⁱ	2.2588	Mo1—Ca1^xvii	3.6886 (1)
Pr1—O2	2.2588	Mo1—Ca1^xviii	3.6886 (1)
Pr1—O1ⁱⁱ	2.5930 (18)	Mo1—Ca1^xix	3.6886 (1)
Pr1—O1ⁱⁱⁱ	2.5930 (18)	Mo1—Ca1^xx	3.6886 (1)
Pr1—O1^iv	2.5930 (18)	Mo1—Ca1^xxi	3.6886 (1)
Pr1—O1^v	2.5930 (18)	Mo1—Ca1^xxii	3.6886 (1)
Pr1—O1^vi	2.5930 (18)	O1—Mo1^xxiii	2.0046 (10)
Pr1—O1^vii	2.5930 (18)	O1—Mo1^xxiv	2.0046 (10)
Pr1—Pr1^vii	3.6886 (1)	O1—Pr1^vii	2.5930 (18)
Pr1—Ca1^viii	3.6886 (1)	O1—Ca1^vii	2.5930 (18)
Pr1—Ca1^ix	3.6886 (1)	O1—Ca1^xxv	2.5930 (18)
Pr1—Ca1^x	3.6886 (1)	O1—Pr1^xxv	2.5930 (18)
Mo1—O1^xi	2.0046 (10)	O2—Ca1^xxv	2.2588
Mo1—O1^xii	2.0046 (10)	O2—Pr1^vii	2.2588
Mo1—O1^xiii	2.0046 (10)	O2—Pr1^ix	2.2588
Mo1—O1^xiv	2.0046 (10)	O2—Pr1^xxv	2.2588
Mo1—O1^xv	2.0046 (10)	O2—Ca1^vii	2.2588
Mo1—O1^xvi	2.0046 (10)	O2—Ca1^ix	2.2588

O2ⁱ—Pr1—O2	180.0	O1^xii—Mo1—Ca1^xvii	42.51 (5)
O2ⁱ—Pr1—O1ⁱⁱ	79.93 (4)	O1^xiii—Mo1—Ca1^xvii	137.49 (5)
O2—Pr1—O1ⁱⁱ	100.07 (4)	O1^xiv—Mo1—Ca1^xvii	90.0
O2ⁱ—Pr1—O1ⁱⁱⁱ	79.93 (4)	O1^xv—Mo1—Ca1^xvii	137.49 (5)
O2—Pr1—O1ⁱⁱⁱ	100.07 (4)	O1^xvi—Mo1—Ca1^xvii	42.51 (5)
O1ⁱⁱ—Pr1—O1ⁱⁱⁱ	117.01 (2)	O1^xi—Mo1—Ca1^xviii	42.51 (5)
O2ⁱ—Pr1—O1^iv	79.93 (4)	O1^xii—Mo1—Ca1^xviii	90.0
O2—Pr1—O1^iv	100.07 (4)	O1^xiii—Mo1—Ca1^xviii	137.49 (5)
O1ⁱⁱ—Pr1—O1^iv	117.01 (2)	O1^xiv—Mo1—Ca1^xviii	137.49 (5)
O1ⁱⁱⁱ—Pr1—O1^iv	117.01 (2)	O1^xv—Mo1—Ca1^xviii	90.0
O2ⁱ—Pr1—O1^v	100.07 (4)	O1^xvi—Mo1—Ca1^xviii	42.51 (5)
O2—Pr1—O1^v	79.93 (4)	Ca1^xvii—Mo1—Ca1^xviii	60.0
O1ⁱⁱ—Pr1—O1^v	180.00 (8)	O1^xi—Mo1—Ca1^xix	42.51 (5)
O1ⁱⁱⁱ—Pr1—O1^v	62.99 (2)	O1^xii—Mo1—Ca1^xix	137.49 (5)
O1^iv—Pr1—O1^v	62.99 (2)	O1^xiii—Mo1—Ca1^xix	90.0
O2ⁱ—Pr1—O1^vi	100.07 (4)	O1^xiv—Mo1—Ca1^xix	137.49 (5)
O2—Pr1—O1^vi	79.93 (4)	O1^xv—Mo1—Ca1^xix	42.51 (5)
O1ⁱⁱ—Pr1—O1^vi	62.99 (2)	O1^xvi—Mo1—Ca1^xix	90.0
O1ⁱⁱⁱ—Pr1—O1^vi	180.00 (8)	Ca1^xvii—Mo1—Ca1^xix	120.0
O1^iv—Pr1—O1^vi	62.99 (2)	Ca1^xviii—Mo1—Ca1^xix	60.0
O1^v—Pr1—O1^vi	117.01 (2)	O1^xi—Mo1—Ca1^xx	137.49 (5)
O2ⁱ—Pr1—O1^vii	100.07 (4)	O1^xii—Mo1—Ca1^xx	90.0
O2—Pr1—O1^vii	79.93 (4)	O1^xiii—Mo1—Ca1^xx	42.51 (5)
O1ⁱⁱ—Pr1—O1^vii	62.99 (2)	O1^xiv—Mo1—Ca1^xx	42.51 (5)
O1ⁱⁱⁱ—Pr1—O1^vii	62.99 (2)	O1^xv—Mo1—Ca1^xx	90.0
O1^iv—Pr1—O1^vii	180.00 (8)	O1^xvi—Mo1—Ca1^xx	137.49 (5)
O1^v—Pr1—O1^vii	117.01 (2)	Ca1^xvii—Mo1—Ca1^xx	120.0
O1^vi—Pr1—O1^vii	117.01 (2)	Ca1^xviii—Mo1—Ca1^xx	180.0
O2ⁱ—Pr1—Pr1^vii	144.7	Ca1^xix—Mo1—Ca1^xx	120.0
O2—Pr1—Pr1^vii	35.3	O1^xi—Mo1—Ca1^xxi	90.0
O1ⁱⁱ—Pr1—Pr1^vii	135.34 (4)	O1^xii—Mo1—Ca1^xxi	137.49 (5)
O1ⁱⁱⁱ—Pr1—Pr1^vii	81.87 (4)	O1^xiii—Mo1—Ca1^xxi	42.51 (5)
O1^iv—Pr1—Pr1^vii	81.87 (4)	O1^xiv—Mo1—Ca1^xxi	90.0
O1^v—Pr1—Pr1^vii	44.66 (4)	O1^xv—Mo1—Ca1^xxi	42.51 (5)
O1^vi—Pr1—Pr1^vii	98.13 (4)	O1^xvi—Mo1—Ca1^xxi	137.49 (5)
O1^vii—Pr1—Pr1^vii	98.13 (4)	Ca1^xvii—Mo1—Ca1^xxi	180.0
O2ⁱ—Pr1—Ca1^viii	35.3	Ca1^xviii—Mo1—Ca1^xxi	120.0
O2—Pr1—Ca1^viii	144.7	Ca1^xix—Mo1—Ca1^xxi	60.0
O1ⁱⁱ—Pr1—Ca1^viii	44.66 (4)	Ca1^xx—Mo1—Ca1^xxi	60.0
O1ⁱⁱⁱ—Pr1—Ca1^viii	98.13 (4)	O1^xi—Mo1—Ca1^xxii	137.49 (5)
O1^iv—Pr1—Ca1^viii	98.13 (4)	O1^xii—Mo1—Ca1^xxii	42.51 (5)
O1^v—Pr1—Ca1^viii	135.34 (4)	O1^xiii—Mo1—Ca1^xxii	90.0
O1^vi—Pr1—Ca1^viii	81.87 (4)	O1^xiv—Mo1—Ca1^xxii	42.51 (5)
O1^vii—Pr1—Ca1^viii	81.87 (4)	O1^xv—Mo1—Ca1^xxii	137.49 (5)
Pr1^vii—Pr1—Ca1^viii	180.0	O1^xvi—Mo1—Ca1^xxii	90.0
O2ⁱ—Pr1—Ca1^ix	144.7	Ca1^xvii—Mo1—Ca1^xxii	60.0
O2—Pr1—Ca1^ix	35.3	Ca1^xviii—Mo1—Ca1^xxii	120.0
O1ⁱⁱ—Pr1—Ca1^ix	81.87 (4)	Ca1^xix—Mo1—Ca1^xxii	180.0
O1ⁱⁱⁱ—Pr1—Ca1^ix	81.87 (4)	Ca1^xx—Mo1—Ca1^xxii	60.0
O1^iv—Pr1—Ca1^ix	135.34 (4)	Ca1^xxi—Mo1—Ca1^xxii	120.0
O1^v—Pr1—Ca1^ix	98.13 (4)	Mo1^xxiii—O1—Mo1^xxiv	133.86 (14)
O1^vi—Pr1—Ca1^ix	98.13 (4)	Mo1^xxiii—O1—Pr1^vii	105.99 (3)
O1^vii—Pr1—Ca1^ix	44.66 (4)	Mo1^xxiv—O1—Pr1^vii	105.99 (3)
Pr1^vii—Pr1—Ca1^ix	60.0	Mo1^xxiii—O1—Ca1^vii	105.99 (3)
Ca1^viii—Pr1—Ca1^ix	120.0	Mo1^xxiv—O1—Ca1^vii	105.99 (3)
O2ⁱ—Pr1—Ca1^x	35.3	Mo1^xxiii—O1—Ca1^xxv	105.99 (3)
O2—Pr1—Ca1^x	144.7	Mo1^xxiv—O1—Ca1^xxv	105.99 (3)
O1ⁱⁱ—Pr1—Ca1^x	98.13 (4)	Pr1^vii—O1—Ca1^xxv	90.68 (8)
O1ⁱⁱⁱ—Pr1—Ca1^x	98.13 (4)	Ca1^vii—O1—Ca1^xxv	90.68 (8)
O1^iv—Pr1—Ca1^x	44.66 (4)	Mo1^xxiii—O1—Pr1^xxv	105.99 (3)
O1^v—Pr1—Ca1^x	81.87 (4)	Mo1^xxiv—O1—Pr1^xxv	105.99 (3)
O1^vi—Pr1—Ca1^x	81.87 (4)	Pr1^vii—O1—Pr1^xxv	90.68 (8)
O1^vii—Pr1—Ca1^x	135.34 (4)	Ca1^vii—O1—Pr1^xxv	90.68 (8)
Pr1^vii—Pr1—Ca1^x	120.0	Pr1—O2—Ca1^xxv	109.5
Ca1^viii—Pr1—Ca1^x	60.0	Pr1—O2—Pr1^vii	109.5
Ca1^ix—Pr1—Ca1^x	180.0	Ca1^xxv—O2—Pr1^vii	109.5
O1^xi—Mo1—O1^xii	94.97 (9)	Pr1—O2—Pr1^ix	109.5
O1^xi—Mo1—O1^xiii	94.97 (9)	Ca1^xxv—O2—Pr1^ix	109.5
O1^xii—Mo1—O1^xiii	94.97 (9)	Pr1^vii—O2—Pr1^ix	109.5
O1^xi—Mo1—O1^xiv	180.0	Pr1—O2—Pr1^xxv	109.5
O1^xii—Mo1—O1^xiv	85.03 (9)	Pr1^vii—O2—Pr1^xxv	109.5
O1^xiii—Mo1—O1^xiv	85.03 (9)	Pr1^ix—O2—Pr1^xxv	109.5
O1^xi—Mo1—O1^xv	85.03 (9)	Pr1—O2—Ca1^vii	109.5
O1^xii—Mo1—O1^xv	180.0	Ca1^xxv—O2—Ca1^vii	109.5
O1^xiii—Mo1—O1^xv	85.03 (9)	Pr1^ix—O2—Ca1^vii	109.5
O1^xiv—Mo1—O1^xv	94.97 (9)	Pr1^xxv—O2—Ca1^vii	109.5
O1^xi—Mo1—O1^xvi	85.03 (9)	Pr1—O2—Ca1^ix	109.5
O1^xii—Mo1—O1^xvi	85.03 (9)	Ca1^xxv—O2—Ca1^ix	109.5
O1^xiii—Mo1—O1^xvi	180.0	Pr1^vii—O2—Ca1^ix	109.5
O1^xiv—Mo1—O1^xvi	94.97 (9)	Pr1^xxv—O2—Ca1^ix	109.5
O1^xv—Mo1—O1^xvi	94.97 (9)	Ca1^vii—O2—Ca1^ix	109.5
O1^xi—Mo1—Ca1^xvii	90.0

Symmetry codes: (i) −x, −y, −z; (ii) −y, z−1/4, x−1/4; (iii) z−1/4, x−1/4, −y; (iv) x−1/4, y−1/4, −z; (v) y, −z+1/4, −x+1/4; (vi) −z+1/4, −x+1/4, y; (vii) −x+1/4, −y+1/4, z; (viii) −x−1/4, −y−1/4, z; (ix) x, −y+1/4, −z+1/4; (x) x, −y−1/4, −z−1/4; (xi) −y+1/2, −z+1/2, −x+1; (xii) −z+1/2, −x+1, −y+1/2; (xiii) −x+1, −y+1/2, −z+1/2; (xiv) y+1/2, z+1/2, x; (xv) z+1/2, x, y+1/2; (xvi) x, y+1/2, z+1/2; (xvii) −x+1/4, −y+3/4, z+1/2; (xviii) y+1/4, −x+1/2, z+3/4; (xix) x+1/2, −y+1/4, −z+3/4; (xx) y+3/4, −x+1/2, z+1/4; (xxi) −x+3/4, −y+1/4, z+1/2; (xxii) x+1/2, −y+3/4, −z+1/4; (xxiii) x, −y+3/4, −z+3/4; (xxiv) x, y−1/2, z−1/2; (xxv) y+1/4, −x, z+1/4.

Experimental details

Crystal data
Chemical formula	Pr_1.37Ca_0.63Mo₂O₇
M_r	522.18
Crystal system, space group	Cubic, Fd3m
Temperature (K)	293
a (Å)	10.4329 (3)
V (Å³)	1135.57 (6)
Z	8
Radiation type	Mo Kα
µ (mm⁻¹)	16.45
Crystal size (mm)	0.16 × 0.14 × 0.12

Data collection
Diffractometer	Nonius KappaCCD diffractometer
Absorption correction	Analytical (de Meulenaer & Tompa, 1965)
T_min, T_max	0.093, 0.125
No. of measured, independent and observed [I > 2σ(I)] reflections	771, 266, 167
R_int	0.053
(sin θ/λ)_max (Å⁻¹)	1.001

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.027, 0.086, 1.12
No. of reflections	266
No. of parameters	12
Δρ_max, Δρ_min (e Å⁻³)	2.51, −1.55

Computer programs: COLLECT (Nonius, 1998), EVALCCD (Duisenberg et al., 2003), SIR97 (Altomare et al., 1999), SHELXL97 (Sheldrick, 2008), DIAMOND (Brandenburg, 2001).

Acknowledgements

Intensity data were collected on the Nonius KappaCCD X-ray diffactometer system of the `Centre de diffractométrie de l'Université de Rennes I' (www.cdifx.univ-rennes1.fr).

References

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