The structure of Ce₂Al₃Ge₄ refined for the first time from single-crystal X-ray diffraction data

Single crystals of dicerium trialuminium tetra­germanide, Ce₂Al₃Ge₄, have been synthesized from a high-temperature reaction using an eutectic mixture of Al and Ge as a metal flux. Through single-crystal X-ray diffraction it was established that Ce₂Al₃Ge₄ crystallizes in the centrosymmetric space group Cmce (No. 64) with the Ba₂Cd₃Bi₄ structure type (Pearson code oC36). Five atoms com­pose the asymmetric unit, i.e. one Ce, two Al, and two Ge atoms, all in special positions with Wyckoff symbols 8f (Ce), 4a and 8e (Al), and 8e and 8f (Ge). The structure can be described as a three-dimensional network of Al and Ge atoms, with Ce atoms occupying the cavities of the framework.

Computing details

Data collection: SMART (Bruker, 2002); cell refinement: SAINT (Bruker, 2002); data reduction: SAINT (Bruker, 2002); program(s) used to solve structure: SHELXTL (Bruker, 2002); program(s) used to refine structure: SHELXTL (Bruker, 2002); molecular graphics: XP in SHELXTL (Bruker, 2002); software used to prepare material for publication: SHELXTL (Bruker, 2002).

Dicerium trialuminium tetragermanide

Crystal data

Ce2Al3Ge4	F(000) = 1132
Mr = 651.54	Dx = 5.980 Mg m^−3
Orthorhombic, Cmce	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2bc 2	Cell parameters from 402 reflections
a = 6.0581 (17) Å	θ = 2.7–26.3°
b = 15.045 (4) Å	µ = 28.97 mm^−1
c = 7.940 (2) Å	T = 120 K
V = 723.7 (4) Å^3	Plate, silver
Z = 4	0.05 × 0.05 × 0.04 mm

Data collection

Bruker SMART CCD area detector diffractometer	402 independent reflections
Radiation source: fine-focus sealed tube	371 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.031
phi and ω scans	θmax = 26.3°, θmin = 2.7°
Absorption correction: multi-scan (SADABS; Sheldrick, 2003)	h = −7→7
Tmin = 0.259, Tmax = 0.316	k = −18→18
1830 measured reflections	l = −9→9

Refinement

Refinement on F^2	0 restraints
Least-squares matrix: full	Primary atom site location: structure-invariant direct methods
R[F^2 > 2σ(F^2)] = 0.022	Secondary atom site location: difference Fourier map
wR(F^2) = 0.050	w = 1/[σ^2(Fo^2) + (0.026P)^2 + 1.7964P] where P = (Fo^2 + 2Fc^2)/3
S = 1.07	(Δ/σ)max < 0.001
402 reflections	Δρmax = 1.00 e Å^−3
27 parameters	Δρmin = −0.99 e Å^−3

Special details

Experimental. Crystals were selected in the glove box and cut in a Paratone N oil bath to the desired dimensions. A suitable crystal was then chosen mounted on the tip of a glass fiber and quickly placed under the cold nitrogen stream (ca. 120 K) in a Bruker SMART CCD-based diffractometer.

Data collection is performed with four batch runs at φ = 0.00 ° (450 frames), at φ = 90.00 ° (450 frames), at φ = 180.00 ° (450 frames), and at φ = 270.00 (450 frames). Frame width = 0.40 ° in ω. Data are merged, corrected for decay, and treated with multi-scan absorption corrections.

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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 > 2sigma(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 (Ų)

	x	y	z	Uiso*/Ueq
Ce	0.0000	0.11385 (3)	0.41715 (6)	0.00871 (17)
Ge1	0.0000	0.18655 (5)	0.05260 (11)	0.0093 (2)
Ge2	0.2500	0.45123 (5)	0.2500	0.0109 (2)
Al1	0.2500	0.28384 (14)	0.2500	0.0074 (5)
Al2	0.0000	0.0000	0.0000	0.0140 (8)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Ce	0.0076 (3)	0.0091 (2)	0.0094 (3)	0.000	0.000	0.00012 (15)
Ge1	0.0082 (5)	0.0097 (4)	0.0100 (4)	0.000	0.000	0.0003 (3)
Ge2	0.0122 (5)	0.0099 (4)	0.0107 (5)	0.000	−0.0012 (4)	0.000
Al1	0.0090 (13)	0.0045 (10)	0.0087 (12)	0.000	−0.0047 (10)	0.000
Al2	0.0065 (18)	0.0226 (18)	0.0129 (19)	0.000	0.000	0.0083 (14)

Geometric parameters (Å, º)

Ce—Ge1	3.0944 (12)	Ge2—Al2^iii	2.6025 (5)
Ce—Ge2^i	3.1688 (9)	Ge2—Al2^ix	2.6025 (6)
Ce—Ge2^ii	3.1688 (9)	Ge2—Ce^ix	3.1688 (9)
Ce—Ge1^iii	3.1897 (12)	Ge2—Ce^x	3.1688 (9)
Ce—Ge2^iv	3.1996 (8)	Ge2—Ce^vii	3.1996 (8)
Ce—Ge2^iii	3.1996 (8)	Ge2—Ce^iv	3.1996 (8)
Ce—Ge1^v	3.2294 (9)	Al1—Ge1^v	2.6254 (14)
Ce—Ge1^vi	3.2294 (9)	Al1—Ge1^iii	2.8750 (10)
Ce—Al1^vi	3.2551 (18)	Al1—Ge1^viii	2.8750 (10)
Ce—Al1	3.2551 (18)	Al1—Ce^v	3.2551 (18)
Ce—Al1^iv	3.4129 (12)	Al1—Ce^iv	3.4129 (12)
Ce—Al1^iii	3.4129 (12)	Al1—Ce^vii	3.4129 (12)
Ge1—Al1^vi	2.6254 (14)	Al2—Ge2^ii	2.6025 (5)
Ge1—Al1	2.6254 (14)	Al2—Ge2^vii	2.6025 (5)
Ge1—Al2	2.8375 (11)	Al2—Ge2^viii	2.6025 (5)
Ge1—Al1^vii	2.8750 (10)	Al2—Ge2^i	2.6025 (5)
Ge1—Al1^viii	2.8750 (10)	Al2—Ge1^xi	2.8375 (11)
Ge1—Ce^vii	3.1897 (12)	Al2—Ce^v	3.5414 (8)
Ge1—Ce^vi	3.2294 (9)	Al2—Ce^xii	3.5414 (8)
Ge1—Ce^v	3.2294 (9)	Al2—Ce^vi	3.5414 (8)
Ge2—Al1	2.518 (2)	Al2—Ce^xiii	3.5414 (8)
Ge1—Ce—Ge2^i	83.17 (2)	Al1—Ge2—Al2^iii	106.377 (17)
Ge1—Ce—Ge2^ii	83.17 (2)	Al1—Ge2—Al2^ix	106.377 (17)
Ge2^i—Ce—Ge2^ii	57.10 (2)	Al2^iii—Ge2—Al2^ix	147.25 (3)
Ge1—Ce—Ge1^iii	89.01 (2)	Al1—Ge2—Ce^ix	140.542 (15)
Ge2^i—Ce—Ge1^iii	150.240 (13)	Al2^iii—Ge2—Ce^ix	74.99 (2)
Ge2^ii—Ce—Ge1^iii	150.240 (13)	Al2^ix—Ge2—Ce^ix	79.84 (2)
Ge1—Ce—Ge2^iv	151.745 (10)	Al1—Ge2—Ce^x	140.542 (14)
Ge2^i—Ce—Ge2^iv	109.63 (2)	Al2^iii—Ge2—Ce^x	79.84 (2)
Ge2^ii—Ce—Ge2^iv	83.309 (19)	Al2^ix—Ge2—Ce^x	74.99 (2)
Ge1^iii—Ce—Ge2^iv	90.55 (3)	Ce^ix—Ge2—Ce^x	78.92 (3)
Ge1—Ce—Ge2^iii	151.745 (10)	Al1—Ge2—Ce^vii	72.182 (16)
Ge2^i—Ce—Ge2^iii	83.309 (19)	Al2^iii—Ge2—Ce^vii	116.16 (2)
Ge2^ii—Ce—Ge2^iii	109.63 (2)	Al2^ix—Ge2—Ce^vii	74.44 (2)
Ge1^iii—Ce—Ge2^iii	90.55 (3)	Ce^ix—Ge2—Ce^vii	143.95 (2)
Ge2^iv—Ce—Ge2^iii	56.50 (2)	Ce^x—Ge2—Ce^vii	70.37 (2)
Ge1—Ce—Ge1^v	87.12 (2)	Al1—Ge2—Ce^iv	72.182 (16)
Ge2^i—Ce—Ge1^v	137.811 (18)	Al2^iii—Ge2—Ce^iv	74.44 (2)
Ge2^ii—Ce—Ge1^v	81.05 (2)	Al2^ix—Ge2—Ce^iv	116.16 (2)
Ge1^iii—Ce—Ge1^v	69.884 (17)	Ce^ix—Ge2—Ce^iv	70.37 (2)
Ge2^iv—Ce—Ge1^v	66.311 (19)	Ce^x—Ge2—Ce^iv	143.95 (2)
Ge2^iii—Ce—Ge1^v	119.09 (2)	Ce^vii—Ge2—Ce^iv	144.36 (3)
Ge1—Ce—Ge1^vi	87.12 (2)	Ge2—Al1—Ge1	123.88 (4)
Ge2^i—Ce—Ge1^vi	81.05 (2)	Ge2—Al1—Ge1^v	123.88 (4)
Ge2^ii—Ce—Ge1^vi	137.811 (18)	Ge1—Al1—Ge1^v	112.23 (9)
Ge1^iii—Ce—Ge1^vi	69.884 (17)	Ge2—Al1—Ge1^iii	81.09 (4)
Ge2^iv—Ce—Ge1^vi	119.09 (2)	Ge1—Al1—Ge1^iii	106.35 (3)
Ge2^iii—Ce—Ge1^vi	66.311 (19)	Ge1^v—Al1—Ge1^iii	83.76 (3)
Ge1^v—Ce—Ge1^vi	139.42 (3)	Ge2—Al1—Ge1^viii	81.09 (4)
Ge1—Ce—Al1^vi	48.766 (16)	Ge1—Al1—Ge1^viii	83.76 (3)
Ge2^i—Ce—Al1^vi	102.32 (3)	Ge1^v—Al1—Ge1^viii	106.35 (3)
Ge2^ii—Ce—Al1^vi	131.16 (3)	Ge1^iii—Al1—Ge1^viii	162.17 (9)
Ge1^iii—Ce—Al1^vi	52.97 (3)	Ge2—Al1—Ce^v	141.78 (3)
Ge2^iv—Ce—Al1^vi	142.89 (3)	Ge1—Al1—Ce^v	65.61 (4)
Ge2^iii—Ce—Al1^vi	110.914 (18)	Ge1^v—Al1—Ce^v	62.42 (4)
Ge1^v—Ce—Al1^vi	101.57 (3)	Ge1^iii—Al1—Ce^v	135.04 (6)
Ge1^vi—Ce—Al1^vi	47.764 (18)	Ge1^viii—Al1—Ce^v	62.35 (3)
Ge1—Ce—Al1	48.766 (16)	Ge2—Al1—Ce	141.78 (3)
Ge2^i—Ce—Al1	131.16 (3)	Ge1—Al1—Ce	62.42 (4)
Ge2^ii—Ce—Al1	102.32 (3)	Ge1^v—Al1—Ce	65.60 (4)
Ge1^iii—Ce—Al1	52.97 (3)	Ge1^iii—Al1—Ce	62.35 (3)
Ge2^iv—Ce—Al1	110.914 (18)	Ge1^viii—Al1—Ce	135.04 (6)
Ge2^iii—Ce—Al1	142.89 (3)	Ce^v—Al1—Ce	76.44 (5)
Ge1^v—Ce—Al1	47.764 (18)	Ge2—Al1—Ce^iv	63.19 (3)
Ge1^vi—Ce—Al1	101.57 (3)	Ge1—Al1—Ce^iv	165.87 (4)
Al1^vi—Ce—Al1	55.46 (4)	Ge1^v—Al1—Ce^iv	62.17 (3)
Ge1—Ce—Al1^iv	124.40 (4)	Ge1^iii—Al1—Ce^iv	61.10 (3)
Ge2^i—Ce—Al1^iv	152.21 (3)	Ge1^viii—Al1—Ce^iv	110.09 (4)
Ge2^ii—Ce—Al1^iv	117.42 (3)	Ce^v—Al1—Ce^iv	117.62 (3)
Ge1^iii—Ce—Al1^iv	46.71 (3)	Ce—Al1—Ce^iv	104.19 (2)
Ge2^iv—Ce—Al1^iv	44.63 (4)	Ge2—Al1—Ce^vii	63.19 (3)
Ge2^iii—Ce—Al1^iv	73.05 (3)	Ge1—Al1—Ce^vii	62.17 (3)
Ge1^v—Ce—Al1^iv	51.203 (17)	Ge1^v—Al1—Ce^vii	165.87 (4)
Ge1^vi—Ce—Al1^iv	101.88 (3)	Ge1^iii—Al1—Ce^vii	110.09 (4)
Al1^vi—Ce—Al1^iv	99.66 (2)	Ge1^viii—Al1—Ce^vii	61.10 (3)
Al1—Ce—Al1^iv	75.81 (2)	Ce^v—Al1—Ce^vii	104.19 (2)
Ge1—Ce—Al1^iii	124.40 (4)	Ce—Al1—Ce^vii	117.62 (3)
Ge2^i—Ce—Al1^iii	117.42 (3)	Ce^iv—Al1—Ce^vii	126.38 (7)
Ge2^ii—Ce—Al1^iii	152.21 (3)	Ge2^ii—Al2—Ge2^vii	180.00 (3)
Ge1^iii—Ce—Al1^iii	46.71 (3)	Ge2^ii—Al2—Ge2^viii	108.82 (2)
Ge2^iv—Ce—Al1^iii	73.05 (3)	Ge2^vii—Al2—Ge2^viii	71.18 (2)
Ge2^iii—Ce—Al1^iii	44.63 (4)	Ge2^ii—Al2—Ge2^i	71.18 (2)
Ge1^v—Ce—Al1^iii	101.88 (3)	Ge2^vii—Al2—Ge2^i	108.82 (2)
Ge1^vi—Ce—Al1^iii	51.203 (17)	Ge2^viii—Al2—Ge2^i	180.00 (3)
Al1^vi—Ce—Al1^iii	75.81 (2)	Ge2^ii—Al2—Ge1^xi	80.41 (2)
Al1—Ce—Al1^iii	99.66 (2)	Ge2^vii—Al2—Ge1^xi	99.59 (2)
Al1^iv—Ce—Al1^iii	52.69 (2)	Ge2^viii—Al2—Ge1^xi	99.59 (2)
Al1^vi—Ge1—Al1	70.46 (5)	Ge2^i—Al2—Ge1^xi	80.41 (2)
Al1^vi—Ge1—Al2	129.74 (5)	Ge2^ii—Al2—Ge1	99.59 (2)
Al1—Ge1—Al2	129.74 (5)	Ge2^vii—Al2—Ge1	80.41 (2)
Al1^vi—Ge1—Al1^vii	96.24 (3)	Ge2^viii—Al2—Ge1	80.41 (2)
Al1—Ge1—Al1^vii	135.76 (3)	Ge2^i—Al2—Ge1	99.59 (2)
Al2—Ge1—Al1^vii	91.73 (5)	Ge1^xi—Al2—Ge1	180.0
Al1^vi—Ge1—Al1^viii	135.76 (3)	Ge2^ii—Al2—Ce^v	59.797 (18)
Al1—Ge1—Al1^viii	96.24 (3)	Ge2^vii—Al2—Ce^v	120.203 (19)
Al2—Ge1—Al1^viii	91.73 (5)	Ge2^viii—Al2—Ce^v	60.498 (18)
Al1^vii—Ge1—Al1^viii	63.58 (3)	Ge2^i—Al2—Ce^v	119.502 (18)
Al1^vi—Ge1—Ce	68.81 (4)	Ge1^xi—Al2—Ce^v	120.380 (11)
Al1—Ge1—Ce	68.81 (4)	Ge1—Al2—Ce^v	59.620 (11)
Al2—Ge1—Ce	77.76 (2)	Ge2^ii—Al2—Ce^xii	120.203 (19)
Al1^vii—Ge1—Ce	146.78 (2)	Ge2^vii—Al2—Ce^xii	59.797 (18)
Al1^viii—Ge1—Ce	146.78 (2)	Ge2^viii—Al2—Ce^xii	119.502 (18)
Al1^vi—Ge1—Ce^vii	71.12 (4)	Ge2^i—Al2—Ce^xii	60.498 (18)
Al1—Ge1—Ce^vii	71.12 (4)	Ge1^xi—Al2—Ce^xii	59.620 (11)
Al2—Ge1—Ce^vii	151.83 (3)	Ge1—Al2—Ce^xii	120.380 (11)
Al1^vii—Ge1—Ce^vii	64.68 (4)	Ce^v—Al2—Ce^xii	180.000 (11)
Al1^viii—Ge1—Ce^vii	64.68 (4)	Ge2^ii—Al2—Ce^vi	119.502 (18)
Ce—Ge1—Ce^vii	130.41 (3)	Ge2^vii—Al2—Ce^vi	60.498 (18)
Al1^vi—Ge1—Ce^vi	66.63 (3)	Ge2^viii—Al2—Ce^vi	120.203 (18)
Al1—Ge1—Ce^vi	133.28 (3)	Ge2^i—Al2—Ce^vi	59.797 (18)
Al2—Ge1—Ce^vi	71.091 (17)	Ge1^xi—Al2—Ce^vi	120.380 (11)
Al1^vii—Ge1—Ce^vi	67.70 (2)	Ge1—Al2—Ce^vi	59.620 (11)
Al1^viii—Ge1—Ce^vi	127.50 (3)	Ce^v—Al2—Ce^vi	117.59 (2)
Ce—Ge1—Ce^vi	79.089 (18)	Ce^xii—Al2—Ce^vi	62.41 (2)
Ce^vii—Ge1—Ce^vi	110.117 (17)	Ge2^ii—Al2—Ce^xiii	60.498 (18)
Al1^vi—Ge1—Ce^v	133.28 (3)	Ge2^vii—Al2—Ce^xiii	119.502 (18)
Al1—Ge1—Ce^v	66.63 (3)	Ge2^viii—Al2—Ce^xiii	59.797 (18)
Al2—Ge1—Ce^v	71.091 (16)	Ge2^i—Al2—Ce^xiii	120.203 (18)
Al1^vii—Ge1—Ce^v	127.50 (3)	Ge1^xi—Al2—Ce^xiii	59.620 (11)
Al1^viii—Ge1—Ce^v	67.70 (2)	Ge1—Al2—Ce^xiii	120.380 (11)
Ce—Ge1—Ce^v	79.089 (18)	Ce^v—Al2—Ce^xiii	62.41 (2)
Ce^vii—Ge1—Ce^v	110.117 (17)	Ce^xii—Al2—Ce^xiii	117.59 (2)
Ce^vi—Ge1—Ce^v	139.42 (3)	Ce^vi—Al2—Ce^xiii	180.0

Symmetry codes: (i) x−1/2, y−1/2, z; (ii) x, y−1/2, −z+1/2; (iii) −x, −y+1/2, z+1/2; (iv) −x+1/2, −y+1/2, −z+1; (v) x+1/2, y, −z+1/2; (vi) x−1/2, y, −z+1/2; (vii) −x, −y+1/2, z−1/2; (viii) −x+1/2, −y+1/2, −z; (ix) x+1/2, y+1/2, z; (x) x, y+1/2, −z+1/2; (xi) −x, −y, −z; (xii) −x−1/2, −y, z−1/2; (xiii) −x+1/2, −y, z−1/2.