Literature DB >> 21578545

Non-isovalent substitution in a Zintl phase with the TiNiSi type structure, CaMg(1-x)Ag(x)Ge [x = 0.13 (3)].

Charles Banenzoué, Siméon Ponou, John Ngolui Lambi.

Abstract

Single crystals of the title Ag-substituted calcium magnesium germanide, CaMg(1-x)Ag(x)Ge [x = 0.13 (3)] were obtained from the reaction of the corresponding elements at high temperature. The compound crystallizes with the TiNiSi structure type (Pearson code oP12) and represents an Ag-substituted derivative of the Zintl phase CaMgGe in which a small fraction of the divalent Mg atoms have been replaced by monovalent Ag atoms. All three atoms in the asymmetric unit (Ca, Mg/Ag, Ge) occupy special positions with the same site symmetry (.m.). Although the end member CaAgGe has been reported in an isomorphic superstructure of the same TiNiSi type, higher Ag content in solid solutions could not be achieved due to competitive formation of other, perhaps more stable, phases.

Entities: Chemical Disease Species

Year: 2009 PMID： 21578545 PMCID： PMC2971942 DOI： 10.1107/S1600536809048454

Source DB: PubMed Journal: Acta Crystallogr Sect E Struct Rep Online ISSN： 1600-5368

Related literature

For the KHg2 structure type, see: Duwell & Baenziger (1955 ▶) and for the TiNiSi structure type, see: Shoemaker & Shoemaker (1965 ▶); Eisenmann et al. (1972 ▶); Villars & Calvert (1991 ▶). For the structural systematics and properties of the TiNiSi structure type, see: Kauzlarich (1996 ▶); Landrum et al. (1998 ▶). For related compounds, see: Ponou & Lidin (2008 ▶); Ponou et al. (2007 ▶). For atomic radii, see: Pauling (1960 ▶).

Experimental

Crystal data

CaMg0.87Ag0.13Ge M = 147.84 Orthorhombic, a = 7.5128 (2) Å b = 4.4573 (1) Å c = 8.3911 (2) Å V = 280.99 (1) Å3 Z = 4 Mo Kα radiation μ = 13.43 mm−1 T = 293 K 0.10 × 0.06 × 0.04 mm

Data collection

Oxford Xcalibur3 diffractometer Absorption correction: multi-scan (CrysAlis RED; Oxford Diffraction, 2007 ▶) T min = 0.396, T max = 0.584 2462 measured reflections 516 independent reflections 481 reflections with I > 2σ(I) R int = 0.026

Refinement

R[F 2 > 2σ(F 2)] = 0.019 wR(F 2) = 0.041 S = 1.10 516 reflections 21 parameters Δρmax = 0.89 e Å−3 Δρmin = −0.44 e Å−3 Data collection: CrysAlis CCD (Oxford Diffraction, 2007 ▶); cell refinement: CrysAlis RED (Oxford Diffraction, 2007 ▶); data reduction: CrysAlis RED; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: DIAMOND (Brandenburg, 1999 ▶); software used to prepare material for publication: SHELXTL (Sheldrick, 2008 ▶). Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536809048454/hb5206sup1.cif Structure factors: contains datablocks I. DOI: 10.1107/S1600536809048454/hb5206Isup2.hkl Additional supplementary materials: crystallographic information; 3D view; checkCIF report

CaMg_0.87Ag_0.13Ge	F(000) = 273.5
M_r = 147.84	D_x = 3.495 Mg m⁻³
Orthorhombic, Pnma	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ac 2n	Cell parameters from 2462 reflections
a = 7.5128 (2) Å	θ = 4.9–32.1°
b = 4.4573 (1) Å	µ = 13.43 mm⁻¹
c = 8.3911 (2) Å	T = 293 K
V = 280.99 (1) Å³	Irregular block, grey
Z = 4	0.10 × 0.06 × 0.04 mm

Oxford Xcalibur3 diffractometer	516 independent reflections
Radiation source: Enhance (Mo) X-ray Source	481 reflections with I > 2σ(I)
graphite	R_int = 0.026
Detector resolution: 16.5467 pixels mm^-1	θ_max = 32.1°, θ_min = 4.6°
ω scans	h = −8→10
Absorption correction: multi-scan (CrysAlis RED; Oxford Diffraction, 2007)	k = −5→6
T_min = 0.396, T_max = 0.584	l = −12→12
2462 measured reflections

Refinement on F²	0 restraints
Least-squares matrix: full	w = 1/[σ²(F_o²) + (0.0233P)²] where P = (F_o² + 2F_c²)/3
R[F² > 2σ(F²)] = 0.019	(Δ/σ)_max < 0.001
wR(F²) = 0.041	Δρ_max = 0.89 e Å⁻³
S = 1.10	Δρ_min = −0.44 e Å⁻³
516 reflections	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc^*=kFc[1+0.001xFc²λ³/sin(2θ)]^-1/4
21 parameters	Extinction coefficient: 0.084 (3)

Experimental. CrysAlis RED, (Oxford Diffraction, 2007) Empirical absorption correction using spherical harmonics, implemented in SCALE3 ABSPACK scaling algorithm.

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.

	x	y	z	U_iso*/U_eq	Occ. (<1)
Ge1	0.76875 (4)	0.2500	0.38457 (3)	0.00994 (12)
Ag1	0.14396 (8)	0.2500	0.43738 (7)	0.0140 (2)	0.1309 (15)
Mg1	0.14396 (8)	0.2500	0.43738 (7)	0.0140 (2)	0.8691 (15)
Ca1	0.51982 (7)	0.2500	0.68206 (7)	0.01280 (14)

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Ge1	0.00976 (16)	0.00827 (16)	0.01178 (17)	0.000	−0.00007 (9)	0.000
Ag1	0.0172 (4)	0.0124 (3)	0.0124 (3)	0.000	−0.0020 (2)	0.000
Mg1	0.0172 (4)	0.0124 (3)	0.0124 (3)	0.000	−0.0020 (2)	0.000
Ca1	0.0119 (3)	0.0134 (3)	0.0131 (3)	0.000	−0.00085 (18)	0.000

Ge1—Mg1ⁱ	2.7621 (4)	Ag1—Ag1^viii	3.2788 (9)
Ge1—Ag1ⁱ	2.7621 (4)	Ag1—Mg1^ix	3.2788 (9)
Ge1—Mg1ⁱⁱ	2.7621 (4)	Ag1—Ag1^ix	3.2788 (9)
Ge1—Ag1ⁱⁱ	2.7621 (4)	Ag1—Ca1^x	3.3267 (8)
Ge1—Ag1ⁱⁱⁱ	2.8535 (7)	Ag1—Ca1^xi	3.3273 (6)
Ge1—Mg1ⁱⁱⁱ	2.8535 (7)	Ag1—Ca1^xii	3.3273 (6)
Ge1—Mg1^iv	2.8596 (7)	Ag1—Ca1	3.4912 (8)
Ge1—Ag1^iv	2.8596 (7)	Ca1—Ge1ⁱⁱ	3.1590 (4)
Ge1—Ca1	3.1191 (6)	Ca1—Ge1ⁱ	3.1590 (4)
Ge1—Ca1ⁱⁱ	3.1590 (4)	Ca1—Ge1^xiii	3.2214 (4)
Ge1—Ca1ⁱ	3.1590 (4)	Ca1—Ge1^xiv	3.2214 (4)
Ge1—Ca1^v	3.2214 (4)	Ca1—Mg1^xv	3.3267 (8)
Ag1—Ge1ⁱ	2.7621 (4)	Ca1—Ag1^xv	3.3267 (8)
Ag1—Ge1ⁱⁱ	2.7621 (4)	Ca1—Mg1^xvi	3.3273 (6)
Ag1—Ge1^vi	2.8535 (7)	Ca1—Ag1^xvi	3.3273 (6)
Ag1—Ge1^vii	2.8596 (7)	Ca1—Mg1^xvii	3.3273 (6)
Ag1—Mg1^viii	3.2788 (9)	Ca1—Ag1^xvii	3.3273 (6)

Mg1ⁱ—Ge1—Ag1ⁱ	0.00 (2)	Ge1ⁱ—Ag1—Ca1^x	63.086 (14)
Mg1ⁱ—Ge1—Mg1ⁱⁱ	107.58 (2)	Ge1ⁱⁱ—Ag1—Ca1^x	63.086 (14)
Ag1ⁱ—Ge1—Mg1ⁱⁱ	107.58 (2)	Ge1^vi—Ag1—Ca1^x	82.653 (19)
Mg1ⁱ—Ge1—Ag1ⁱⁱ	107.58 (2)	Ge1^vii—Ag1—Ca1^x	177.14 (3)
Ag1ⁱ—Ge1—Ag1ⁱⁱ	107.58 (2)	Mg1^viii—Ag1—Ca1^x	60.49 (2)
Mg1ⁱⁱ—Ge1—Ag1ⁱⁱ	0.0	Ag1^viii—Ag1—Ca1^x	60.49 (2)
Mg1ⁱ—Ge1—Ag1ⁱⁱⁱ	71.425 (16)	Mg1^ix—Ag1—Ca1^x	60.49 (2)
Ag1ⁱ—Ge1—Ag1ⁱⁱⁱ	71.425 (16)	Ag1^ix—Ag1—Ca1^x	60.49 (2)
Mg1ⁱⁱ—Ge1—Ag1ⁱⁱⁱ	71.425 (16)	Ge1ⁱ—Ag1—Ca1^xi	167.565 (19)
Ag1ⁱⁱ—Ge1—Ag1ⁱⁱⁱ	71.425 (16)	Ge1ⁱⁱ—Ag1—Ca1^xi	84.010 (9)
Mg1ⁱ—Ge1—Mg1ⁱⁱⁱ	71.425 (16)	Ge1^vi—Ag1—Ca1^xi	62.269 (13)
Ag1ⁱ—Ge1—Mg1ⁱⁱⁱ	71.425 (16)	Ge1^vii—Ag1—Ca1^xi	60.851 (14)
Mg1ⁱⁱ—Ge1—Mg1ⁱⁱⁱ	71.425 (16)	Mg1^viii—Ag1—Ca1^xi	60.470 (16)
Ag1ⁱⁱ—Ge1—Mg1ⁱⁱⁱ	71.425 (16)	Ag1^viii—Ag1—Ca1^xi	60.470 (16)
Ag1ⁱⁱⁱ—Ge1—Mg1ⁱⁱⁱ	0.00 (2)	Mg1^ix—Ag1—Ca1^xi	114.69 (3)
Mg1ⁱ—Ge1—Mg1^iv	126.076 (12)	Ag1^ix—Ag1—Ca1^xi	114.69 (3)
Ag1ⁱ—Ge1—Mg1^iv	126.076 (12)	Ca1^x—Ag1—Ca1^xi	120.958 (16)
Mg1ⁱⁱ—Ge1—Mg1^iv	126.075 (12)	Ge1ⁱ—Ag1—Ca1^xii	84.010 (9)
Ag1ⁱⁱ—Ge1—Mg1^iv	126.075 (12)	Ge1ⁱⁱ—Ag1—Ca1^xii	167.565 (19)
Ag1ⁱⁱⁱ—Ge1—Mg1^iv	118.073 (19)	Ge1^vi—Ag1—Ca1^xii	62.269 (13)
Mg1ⁱⁱⁱ—Ge1—Mg1^iv	118.073 (19)	Ge1^vii—Ag1—Ca1^xii	60.851 (14)
Mg1ⁱ—Ge1—Ag1^iv	126.076 (12)	Mg1^viii—Ag1—Ca1^xii	114.69 (3)
Ag1ⁱ—Ge1—Ag1^iv	126.076 (12)	Ag1^viii—Ag1—Ca1^xii	114.69 (3)
Mg1ⁱⁱ—Ge1—Ag1^iv	126.075 (12)	Mg1^ix—Ag1—Ca1^xii	60.470 (16)
Ag1ⁱⁱ—Ge1—Ag1^iv	126.075 (12)	Ag1^ix—Ag1—Ca1^xii	60.470 (16)
Ag1ⁱⁱⁱ—Ge1—Ag1^iv	118.073 (19)	Ca1^x—Ag1—Ca1^xii	120.958 (16)
Mg1ⁱⁱⁱ—Ge1—Ag1^iv	118.073 (19)	Ca1^xi—Ag1—Ca1^xii	84.104 (19)
Mg1^iv—Ge1—Ag1^iv	0.00 (2)	Ge1ⁱ—Ag1—Ca1	59.328 (12)
Mg1ⁱ—Ge1—Ca1	73.110 (14)	Ge1ⁱⁱ—Ag1—Ca1	59.328 (12)
Ag1ⁱ—Ge1—Ca1	73.110 (14)	Ge1^vi—Ag1—Ca1	152.91 (2)
Mg1ⁱⁱ—Ge1—Ca1	73.110 (14)	Ge1^vii—Ag1—Ca1	106.88 (2)
Ag1ⁱⁱ—Ge1—Ca1	73.110 (14)	Mg1^viii—Ag1—Ca1	110.19 (2)
Ag1ⁱⁱⁱ—Ge1—Ca1	117.905 (19)	Ag1^viii—Ag1—Ca1	110.19 (2)
Mg1ⁱⁱⁱ—Ge1—Ca1	117.905 (19)	Mg1^ix—Ag1—Ca1	110.19 (2)
Mg1^iv—Ge1—Ca1	124.022 (18)	Ag1^ix—Ag1—Ca1	110.19 (2)
Ag1^iv—Ge1—Ca1	124.022 (18)	Ca1^x—Ag1—Ca1	70.261 (14)
Mg1ⁱ—Ge1—Ca1ⁱⁱ	145.884 (18)	Ca1^xi—Ag1—Ca1	132.669 (11)
Ag1ⁱ—Ge1—Ca1ⁱⁱ	145.884 (18)	Ca1^xii—Ag1—Ca1	132.669 (11)
Mg1ⁱⁱ—Ge1—Ca1ⁱⁱ	71.906 (14)	Ge1—Ca1—Ge1ⁱⁱ	105.655 (14)
Ag1ⁱⁱ—Ge1—Ca1ⁱⁱ	71.906 (14)	Ge1—Ca1—Ge1ⁱ	105.655 (14)
Ag1ⁱⁱⁱ—Ge1—Ca1ⁱⁱ	134.864 (8)	Ge1ⁱⁱ—Ca1—Ge1ⁱ	89.738 (15)
Mg1ⁱⁱⁱ—Ge1—Ca1ⁱⁱ	134.864 (8)	Ge1—Ca1—Ge1^xiii	97.268 (13)
Mg1^iv—Ge1—Ca1ⁱⁱ	66.910 (14)	Ge1ⁱⁱ—Ca1—Ge1^xiii	156.90 (2)
Ag1^iv—Ge1—Ca1ⁱⁱ	66.910 (14)	Ge1ⁱ—Ca1—Ge1^xiii	86.771 (6)
Ca1—Ge1—Ca1ⁱⁱ	74.345 (14)	Ge1—Ca1—Ge1^xiv	97.268 (13)
Mg1ⁱ—Ge1—Ca1ⁱ	71.906 (14)	Ge1ⁱⁱ—Ca1—Ge1^xiv	86.771 (6)
Ag1ⁱ—Ge1—Ca1ⁱ	71.906 (14)	Ge1ⁱ—Ca1—Ge1^xiv	156.90 (2)
Mg1ⁱⁱ—Ge1—Ca1ⁱ	145.884 (18)	Ge1^xiii—Ca1—Ge1^xiv	87.548 (14)
Ag1ⁱⁱ—Ge1—Ca1ⁱ	145.884 (18)	Ge1—Ca1—Mg1^xv	126.88 (2)
Ag1ⁱⁱⁱ—Ge1—Ca1ⁱ	134.864 (8)	Ge1ⁱⁱ—Ca1—Mg1^xv	111.240 (16)
Mg1ⁱⁱⁱ—Ge1—Ca1ⁱ	134.864 (8)	Ge1ⁱ—Ca1—Mg1^xv	111.240 (16)
Mg1^iv—Ge1—Ca1ⁱ	66.910 (14)	Ge1^xiii—Ca1—Mg1^xv	49.866 (10)
Ag1^iv—Ge1—Ca1ⁱ	66.910 (14)	Ge1^xiv—Ca1—Mg1^xv	49.866 (10)
Ca1—Ge1—Ca1ⁱ	74.345 (14)	Ge1—Ca1—Ag1^xv	126.88 (2)
Ca1ⁱⁱ—Ge1—Ca1ⁱ	89.738 (15)	Ge1ⁱⁱ—Ca1—Ag1^xv	111.240 (16)
Mg1ⁱ—Ge1—Ca1^v	136.591 (17)	Ge1ⁱ—Ca1—Ag1^xv	111.240 (16)
Ag1ⁱ—Ge1—Ca1^v	136.591 (17)	Ge1^xiii—Ca1—Ag1^xv	49.866 (10)
Mg1ⁱⁱ—Ge1—Ca1^v	67.048 (15)	Ge1^xiv—Ca1—Ag1^xv	49.866 (10)
Ag1ⁱⁱ—Ge1—Ca1^v	67.048 (15)	Mg1^xv—Ca1—Ag1^xv	0.000 (6)
Ag1ⁱⁱⁱ—Ge1—Ca1^v	66.097 (13)	Ge1—Ca1—Mg1^xvi	137.481 (10)
Mg1ⁱⁱⁱ—Ge1—Ca1^v	66.097 (13)	Ge1ⁱⁱ—Ca1—Mg1^xvi	109.433 (18)
Mg1^iv—Ge1—Ca1^v	70.325 (14)	Ge1ⁱ—Ca1—Mg1^xvi	52.239 (12)
Ag1^iv—Ge1—Ca1^v	70.325 (14)	Ge1^xiii—Ca1—Mg1^xvi	51.633 (12)
Ca1—Ge1—Ca1^v	135.874 (8)	Ge1^xiv—Ca1—Mg1^xvi	107.823 (18)
Ca1ⁱⁱ—Ge1—Ca1^v	75.935 (6)	Mg1^xv—Ca1—Mg1^xvi	59.042 (16)
Ca1ⁱ—Ge1—Ca1^v	137.148 (11)	Ag1^xv—Ca1—Mg1^xvi	59.042 (16)
Ge1ⁱ—Ag1—Ge1ⁱⁱ	107.58 (2)	Ge1—Ca1—Ag1^xvi	137.481 (10)
Ge1ⁱ—Ag1—Ge1^vi	108.575 (16)	Ge1ⁱⁱ—Ca1—Ag1^xvi	109.433 (18)
Ge1ⁱⁱ—Ag1—Ge1^vi	108.575 (16)	Ge1ⁱ—Ca1—Ag1^xvi	52.239 (12)
Ge1ⁱ—Ag1—Ge1^vii	115.669 (14)	Ge1^xiii—Ca1—Ag1^xvi	51.633 (12)
Ge1ⁱⁱ—Ag1—Ge1^vii	115.669 (14)	Ge1^xiv—Ca1—Ag1^xvi	107.823 (18)
Ge1^vi—Ag1—Ge1^vii	100.20 (2)	Mg1^xv—Ca1—Ag1^xvi	59.042 (16)
Ge1ⁱ—Ag1—Mg1^viii	122.12 (3)	Ag1^xv—Ca1—Ag1^xvi	59.042 (16)
Ge1ⁱⁱ—Ag1—Mg1^viii	55.586 (12)	Mg1^xvi—Ca1—Ag1^xvi	0.00 (3)
Ge1^vi—Ag1—Mg1^viii	52.990 (18)	Ge1—Ca1—Mg1^xvii	137.481 (10)
Ge1^vii—Ag1—Mg1^viii	121.27 (2)	Ge1ⁱⁱ—Ca1—Mg1^xvii	52.239 (12)
Ge1ⁱ—Ag1—Ag1^viii	122.12 (3)	Ge1ⁱ—Ca1—Mg1^xvii	109.433 (18)
Ge1ⁱⁱ—Ag1—Ag1^viii	55.586 (12)	Ge1^xiii—Ca1—Mg1^xvii	107.823 (18)
Ge1^vi—Ag1—Ag1^viii	52.990 (18)	Ge1^xiv—Ca1—Mg1^xvii	51.633 (12)
Ge1^vii—Ag1—Ag1^viii	121.27 (2)	Mg1^xv—Ca1—Mg1^xvii	59.042 (16)
Mg1^viii—Ag1—Ag1^viii	0.000 (16)	Ag1^xv—Ca1—Mg1^xvii	59.042 (16)
Ge1ⁱ—Ag1—Mg1^ix	55.586 (12)	Mg1^xvi—Ca1—Mg1^xvii	84.104 (19)
Ge1ⁱⁱ—Ag1—Mg1^ix	122.12 (3)	Ag1^xvi—Ca1—Mg1^xvii	84.104 (19)
Ge1^vi—Ag1—Mg1^ix	52.990 (18)	Ge1—Ca1—Ag1^xvii	137.481 (10)
Ge1^vii—Ag1—Mg1^ix	121.27 (2)	Ge1ⁱⁱ—Ca1—Ag1^xvii	52.239 (12)
Mg1^viii—Ag1—Mg1^ix	85.64 (3)	Ge1ⁱ—Ca1—Ag1^xvii	109.433 (18)
Ag1^viii—Ag1—Mg1^ix	85.64 (3)	Ge1^xiii—Ca1—Ag1^xvii	107.823 (18)
Ge1ⁱ—Ag1—Ag1^ix	55.586 (12)	Ge1^xiv—Ca1—Ag1^xvii	51.633 (12)
Ge1ⁱⁱ—Ag1—Ag1^ix	122.12 (3)	Mg1^xv—Ca1—Ag1^xvii	59.042 (16)
Ge1^vi—Ag1—Ag1^ix	52.990 (18)	Ag1^xv—Ca1—Ag1^xvii	59.042 (16)
Ge1^vii—Ag1—Ag1^ix	121.27 (2)	Mg1^xvi—Ca1—Ag1^xvii	84.104 (19)
Mg1^viii—Ag1—Ag1^ix	85.64 (3)	Ag1^xvi—Ca1—Ag1^xvii	84.104 (19)
Ag1^viii—Ag1—Ag1^ix	85.64 (3)	Mg1^xvii—Ca1—Ag1^xvii	0.00 (2)
Mg1^ix—Ag1—Ag1^ix	0.000 (16)

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