Two new compounds, β-ScTe and Y₃Au₂, and a reassessment of Y₂Au

Two new compounds, β-ScTe (scandium telluride) and Y₃Au₂ (triyttrium digold), have been synthesized by high-temperature solid-state techniques and their crystal structures, along with that of Y₂Au (diyttrium gold), have been refined by single-crystal X-ray diffraction methods. β-ScTe is a superstructure of ScTe (NiAs-type), featuring double hexa­gonal close-packed layers of Te atoms with the octa­hedral cavities filled by Sc atoms. Y₃Au₂ displays a U₃Si₂-type structure and is built from Au₂-centered bitrigonal prisms and centered cubes of Y atoms. The structure of Y₂Au is better described as an inverse PbCl₂-type structure rather than a Co₂Si-type.

S1. Comment

Research within solid-state chemistry on ternary and polynary compounds has attracted much attention during the past few decades because of their interesting structures, bonding and physical properties. Knowledge of binary compounds can provide significant references during the exploratory synthesis of polynary compounds, and their identification is therefore valued. Although many binary combinations of elements are covered by binary phase diagrams and the crystal databases, some have been missed because of the limitations of the earlier experiments. For instance, only two compounds, ScTe and Sc₂Te₃, were in the Sc–Te phase diagram reported in 1990 (Reference?), missing several examples, Sc₂Te, Sc₈Te₃ and Sc₉Te₂, which were discovered later during the study of ternary systems (Maggard & Corbett, 1997, 1998, 2000). We discovered that the structure of β-ScTe was still missing, with an inverse Li₂O₂-type structure, a double hexagonal close-packed (dhcp) version of ScTe (NiAs-type) (Men kov et al., 1961). Y₃Au₂ was missed in the investigation of the Y–Au phase diagram (Saccone et al., 1997), whereas Y₂Au was identified as Co₂Si-type (Yakinthos et al., 1978) from lattice parameters only; no refinement of powder diffraction intensities was carried out. The crystal structures of these three phases are described here.

β-ScTe is presumably a high-temperature phase with an inverse Li₂O₂-type structure. A view of one unit cell approximately along [001] is shown in Fig. 1(a) and a section approximately along [100] is shown in Fig. 1(b), in which Te atoms form hexagonal close-packed (hcp) layers with ABAC··· stacking, leaving all nominal octahedral cavities filled by Sc atoms. Note that ScTe (NiAs-type) crystallizes in the same space group, P6₃/mmc, with a = 4.130 (5) Å and c = 6.749 (5) Å, and contains simple hcp Te atoms of ABAB··· ordering with Sc atoms occupying the octahedral cavities (Men kov et al., 1961). Therefore, β-ScTe is a stacking variant of ScTe, with a c axis twice as large.

Y₃Au₂ crystallizes in the U₃Si₂-type structure in space group P4/mbm (No. 127). An approximately [001] projection along the short 3.907 (3) Å c axis is shown in Fig. 2. The basic building units are an Au₂-centered bitrigonal prism (BTP) of Y2 and a Y1-centered Y2 cube. The Au₂ unit is an unusual dimer 3.0539 (19) Å long. The two-dimensional motif is created in such a way that each Y2 cube, with the centered Y1 atom on a fourfold axis, interconnects with four identical units through shared Y2–Y2 edges, leaving the cavities filled by the BTPs. The centered Y1 and Au atoms lie on a mirror plane at c = 0. The two-dimensional motif repeats along c to form a three-dimensional network, sharing bitriangular and square faces.

The structure of Y₂Au in space group Pnma projected along [010] is shown in Fig. 3, in which each Au atom forms the center of a trigonal prism (TP) of Y1 or Y2 atoms that shares trigonal faces with identical units to generate an infinite one-dimensional column along b. The TPs interconnect with shared Y2–Y2 edges and lead to the formation of puckered sheets along a. Adjoining sheets stack along c, with displacements of b/2, to create a three-dimensional structural network. As a result, each TP is tricapped by two Y1 atoms and one Y2 atom so that each Au atom has nine neighbors. Y₂Au is better described as an inverse PbCl₂-type structure rather than the earlier reported Co₂Si-type, in which the Si atom would have ten neighbors (Flahaut & Thévet, 1980; Liu & Corbett, 2006).

Related literature

For related literature, see: Flahaut & Thévet (1980); Liu & Corbett (2006); Maggard & Corbett (1997, 1998, 2000); Men kov, Komissarova & Simonav (1961); Saccone et al. (1997); Yakinthos et al. (1978).

S2. Experimental

The formation of all three phases was in fact first noted in powder pattern data from nearby ternary systems. β-ScTe was synthesized from a mixture of Sc and Sc₂Te₃. The latter was obtained from a prereaction of Sc and Te in a 2:3 ratio, sealed in a silica tube under vacuum, heated at 723 K for 12 h and then at 1173 K for 72 h. Y₃Au₂ and Y₂Au were prepared from mixtures of high-purity elements. The three combinations were each pelletized and arc-melted under an argon atmosphere in a glovebox. The pellets were then sealed in tantalum containers and annealed in a graphite-heated vacuum furnace at 1573 K for 200 h for β-ScTe, and at 1323 K for one week for Y₃Au₂ and Y₂Au.

Computing details

For all compounds, data collection: SMART (Bruker, 2002); cell refinement: SAINT-Plus (Bruker, 2003); data reduction: SAINT-Plus (Bruker, 2003); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg, 2000); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures

	Fig. 1. (a) A view of one unit cell, approximately along [001]. (b) A section of β-ScTe, approximately along [100].
	Fig. 2. A projection of Y3Au2, approximately along [001].
	Fig. 3. A view of Y2Au, approximately along [001].

(ScTe) scandium telluride

Crystal data

ScTe	Dx = 5.797 Mg m^−3 Dm = 5.797 Mg m^−3 Dm measured by not measured
Mr = 172.56	Mo Kα radiation, λ = 0.71073 Å
Hexagonal, P63/mmc	Cell parameters from 983 reflections
a = 4.0969 (6) Å	θ = 5.9–28.1°
c = 13.602 (3) Å	µ = 17.64 mm^−1
V = 197.71 (6) Å^3	T = 293 K
Z = 4	Irregularly shaped, black
F(000) = 292	0.15 × 0.08 × 0.07 mm

Data collection

Bruker SMART CCD area-detector diffractometer	92 independent reflections
Radiation source: fine-focus sealed tube	90 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.020
ϕ and ω scans	θmax = 25.0°, θmin = 3.0°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −4→4
Tmin = 0.177, Tmax = 0.372	k = −4→4
1274 measured reflections	l = −15→16

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)] = 0.036	Secondary atom site location: difference Fourier map
wR(F^2) = 0.081	w = 1/[σ^2(Fo^2) + (0.0179P)^2 + 7.5992P] where P = (Fo^2 + 2Fc^2)/3
S = 1.57	(Δ/σ)max < 0.001
92 reflections	Δρmax = 1.21 e Å^−3
8 parameters	Δρmin = −1.65 e Å^−3

Special details

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 (Ų)

	x	y	z	Uiso*/Ueq
Te1	0.3333	0.6667	0.2500	0.0078 (7)
Te2	0.0000	0.0000	0.0000	0.0110 (7)
Sc1	0.3333	0.6667	0.6183 (3)	0.0241 (13)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Te1	0.0079 (8)	0.0079 (8)	0.0077 (10)	0.0039 (4)	0.000	0.000
Te2	0.0100 (8)	0.0100 (8)	0.0130 (11)	0.0050 (4)	0.000	0.000
Sc1	0.0276 (19)	0.0276 (19)	0.017 (2)	0.0138 (10)	0.000	0.000

Geometric parameters (Å, º)

Te1—Sc1^i	2.967 (3)	Te2—Sc1^ix	2.861 (3)
Te1—Sc1^ii	2.967 (3)	Te2—Sc1^iii	2.861 (3)
Te1—Sc1^iii	2.967 (3)	Te2—Sc1^x	2.861 (3)
Te1—Sc1^iv	2.967 (3)	Sc1—Te2^xi	2.861 (3)
Te1—Sc1^v	2.967 (3)	Sc1—Te2^xii	2.861 (3)
Te1—Sc1^vi	2.967 (3)	Sc1—Te2^xiii	2.861 (3)
Te2—Sc1^vii	2.861 (3)	Sc1—Te1^ii	2.967 (3)
Te2—Sc1^i	2.861 (3)	Sc1—Te1^iv	2.967 (3)
Te2—Sc1^viii	2.861 (3)	Sc1—Te1^vi	2.967 (3)
Sc1^i—Te1—Sc1^ii	74.27 (15)	Sc1^i—Te2—Sc1^x	88.55 (11)
Sc1^i—Te1—Sc1^iii	87.33 (11)	Sc1^viii—Te2—Sc1^x	91.45 (11)
Sc1^ii—Te1—Sc1^iii	133.02 (5)	Sc1^ix—Te2—Sc1^x	88.55 (11)
Sc1^i—Te1—Sc1^iv	133.02 (5)	Sc1^iii—Te2—Sc1^x	180.00 (16)
Sc1^ii—Te1—Sc1^iv	87.33 (11)	Te2^xi—Sc1—Te2^xii	91.45 (11)
Sc1^iii—Te1—Sc1^iv	133.02 (5)	Te2^xi—Sc1—Te2^xiii	91.45 (11)
Sc1^i—Te1—Sc1^v	87.33 (11)	Te2^xii—Sc1—Te2^xiii	91.45 (11)
Sc1^ii—Te1—Sc1^v	133.02 (5)	Te2^xi—Sc1—Te1^ii	90.574 (11)
Sc1^iii—Te1—Sc1^v	87.33 (11)	Te2^xii—Sc1—Te1^ii	177.10 (15)
Sc1^iv—Te1—Sc1^v	74.26 (15)	Te2^xiii—Sc1—Te1^ii	90.574 (11)
Sc1^i—Te1—Sc1^vi	133.02 (5)	Te2^xi—Sc1—Te1^iv	177.10 (15)
Sc1^ii—Te1—Sc1^vi	87.33 (11)	Te2^xii—Sc1—Te1^iv	90.574 (11)
Sc1^iii—Te1—Sc1^vi	74.26 (15)	Te2^xiii—Sc1—Te1^iv	90.574 (11)
Sc1^iv—Te1—Sc1^vi	87.33 (11)	Te1^ii—Sc1—Te1^iv	87.33 (10)
Sc1^v—Te1—Sc1^vi	133.02 (5)	Te2^xi—Sc1—Te1^vi	90.574 (11)
Sc1^vii—Te2—Sc1^i	180.00 (16)	Te2^xii—Sc1—Te1^vi	90.573 (11)
Sc1^vii—Te2—Sc1^viii	91.45 (11)	Te2^xiii—Sc1—Te1^vi	177.10 (15)
Sc1^i—Te2—Sc1^viii	88.55 (11)	Te1^ii—Sc1—Te1^vi	87.33 (10)
Sc1^vii—Te2—Sc1^ix	88.55 (11)	Te1^iv—Sc1—Te1^vi	87.33 (10)
Sc1^i—Te2—Sc1^ix	91.45 (11)	Te2^xi—Sc1—Sc1^xiv	124.23 (8)
Sc1^viii—Te2—Sc1^ix	180.00 (16)	Te2^xii—Sc1—Sc1^xiv	124.23 (8)
Sc1^vii—Te2—Sc1^iii	88.55 (11)	Te2^xiii—Sc1—Sc1^xiv	124.23 (8)
Sc1^i—Te2—Sc1^iii	91.45 (11)	Te1^ii—Sc1—Sc1^xiv	52.87 (7)
Sc1^viii—Te2—Sc1^iii	88.55 (11)	Te1^iv—Sc1—Sc1^xiv	52.87 (7)
Sc1^ix—Te2—Sc1^iii	91.45 (11)	Te1^vi—Sc1—Sc1^xiv	52.87 (7)
Sc1^vii—Te2—Sc1^x	91.45 (11)

Symmetry codes: (i) −x+1, −y+1, z−1/2; (ii) −x+1, −y+1, −z+1; (iii) −x, −y+1, z−1/2; (iv) −x+1, −y+2, −z+1; (v) −x+1, −y+2, z−1/2; (vi) −x, −y+1, −z+1; (vii) x−1, y−1, −z+1/2; (viii) x, y, −z+1/2; (ix) −x, −y, z−1/2; (x) x, y−1, −z+1/2; (xi) −x, −y, z+1/2; (xii) −x, −y+1, z+1/2; (xiii) −x+1, −y+1, z+1/2; (xiv) x, y, −z+3/2.

(Y3Au2) triyttrium digold

Crystal data

Y3Au2	Dx = 8.647 Mg m^−3 Dm = 8.647 Mg m^−3 Dm measured by not measured
Mr = 660.66	Mo Kα radiation, λ = 0.71073 Å
Tetragonal, P4/mbm	Cell parameters from 497 reflections
a = 8.059 (3) Å	θ = 3.6–26.5°
c = 3.907 (3) Å	µ = 91.35 mm^−1
V = 253.7 (3) Å^3	T = 293 K
Z = 2	Irregularly shaped, metallic silver
F(000) = 550	0.05 × 0.04 × 0.02 mm

Data collection

Bruker SMART CCD area-detector diffractometer	194 independent reflections
Radiation source: fine-focus sealed tube	156 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.093
ϕ and ω scans	θmax = 28.1°, θmin = 3.6°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −10→10
Tmin = 0.092, Tmax = 0.262	k = −9→10
1866 measured reflections	l = −5→5

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)] = 0.030	Secondary atom site location: difference Fourier map
wR(F^2) = 0.069	w = 1/[σ^2(Fo^2) + (0.P)^2] where P = (Fo^2 + 2Fc^2)/3
S = 0.93	(Δ/σ)max < 0.001
194 reflections	Δρmax = 1.46 e Å^−3
11 parameters	Δρmin = −1.40 e Å^−3

Special details

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 (Ų)

	x	y	z	Uiso*/Ueq
Au1	0.63399 (7)	0.13399 (7)	0.0000	0.0213 (3)
Y1	0.0000	0.0000	0.0000	0.0221 (7)
Y2	0.16226 (19)	0.66226 (19)	0.5000	0.0241 (5)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Au1	0.0227 (4)	0.0227 (4)	0.0184 (5)	−0.0018 (3)	0.000	0.000
Y1	0.0261 (10)	0.0261 (10)	0.0141 (13)	0.000	0.000	0.000
Y2	0.0294 (7)	0.0294 (7)	0.0135 (11)	−0.0039 (8)	0.000	0.000

Geometric parameters (Å, º)

Au1—Y2^i	3.035 (2)	Y1—Au1^xi	3.1409 (13)
Au1—Y2^ii	3.035 (2)	Y1—Au1^xii	3.1409 (13)
Au1—Au1^iii	3.0539 (19)	Y1—Au1^iii	3.1409 (13)
Au1—Y2^iv	3.0932 (19)	Y2—Au1^i	3.035 (2)
Au1—Y2^v	3.0932 (19)	Y2—Au1^ii	3.035 (2)
Au1—Y2^vi	3.0932 (19)	Y2—Au1^xiii	3.0932 (19)
Au1—Y2^vii	3.0932 (19)	Y2—Au1^xiv	3.0932 (19)
Au1—Y1^viii	3.1409 (13)	Y2—Au1^x	3.0932 (19)
Au1—Y1^ix	3.1409 (13)	Y2—Au1^xv	3.0932 (19)
Y1—Au1^x	3.1409 (13)
Y2^i—Au1—Y2^ii	80.15 (8)	Au1^iii—Y1—Y2^xx	126.98 (3)
Y2^i—Au1—Au1^iii	139.92 (4)	Y2^xvi—Y1—Y2^xx	72.84 (2)
Y2^ii—Au1—Au1^iii	139.92 (4)	Y2^vii—Y1—Y2^xx	107.16 (2)
Y2^i—Au1—Y2^iv	141.66 (3)	Y2^xvii—Y1—Y2^xx	65.81 (5)
Y2^ii—Au1—Y2^iv	88.34 (5)	Y2^xviii—Y1—Y2^xx	114.19 (5)
Au1^iii—Au1—Y2^iv	60.42 (2)	Y2^xix—Y1—Y2^xx	107.16 (2)
Y2^i—Au1—Y2^v	141.66 (3)	Y2^v—Y1—Y2^xx	72.84 (2)
Y2^ii—Au1—Y2^v	88.34 (5)	Au1^x—Y1—Y2^xxi	125.85 (4)
Au1^iii—Au1—Y2^v	60.42 (2)	Au1^xi—Y1—Y2^xxi	54.15 (4)
Y2^iv—Au1—Y2^v	73.43 (7)	Au1^xii—Y1—Y2^xxi	126.98 (3)
Y2^i—Au1—Y2^vi	88.34 (5)	Au1^iii—Y1—Y2^xxi	53.02 (3)
Y2^ii—Au1—Y2^vi	141.66 (3)	Y2^xvi—Y1—Y2^xxi	107.16 (2)
Au1^iii—Au1—Y2^vi	60.42 (2)	Y2^vii—Y1—Y2^xxi	72.84 (2)
Y2^iv—Au1—Y2^vi	78.34 (7)	Y2^xvii—Y1—Y2^xxi	114.19 (5)
Y2^v—Au1—Y2^vi	120.84 (4)	Y2^xviii—Y1—Y2^xxi	65.81 (5)
Y2^i—Au1—Y2^vii	88.34 (5)	Y2^xix—Y1—Y2^xxi	72.84 (2)
Y2^ii—Au1—Y2^vii	141.66 (3)	Y2^v—Y1—Y2^xxi	107.16 (2)
Au1^iii—Au1—Y2^vii	60.42 (2)	Y2^xx—Y1—Y2^xxi	180.00 (3)
Y2^iv—Au1—Y2^vii	120.84 (4)	Au1^i—Y2—Au1^ii	80.15 (8)
Y2^v—Au1—Y2^vii	78.34 (7)	Au1^i—Y2—Au1^xiii	149.78 (3)
Y2^vi—Au1—Y2^vii	73.43 (7)	Au1^ii—Y2—Au1^xiii	92.91 (5)
Y2^i—Au1—Y1^viii	71.210 (16)	Au1^i—Y2—Au1^xiv	92.91 (5)
Y2^ii—Au1—Y1^viii	71.210 (16)	Au1^ii—Y2—Au1^xiv	149.78 (3)
Au1^iii—Au1—Y1^viii	114.894 (12)	Au1^xiii—Y2—Au1^xiv	78.34 (7)
Y2^iv—Au1—Y1^viii	138.60 (4)	Au1^i—Y2—Au1^x	149.78 (3)
Y2^v—Au1—Y1^viii	70.46 (3)	Au1^ii—Y2—Au1^x	92.91 (5)
Y2^vi—Au1—Y1^viii	138.60 (4)	Au1^xiii—Y2—Au1^x	59.16 (4)
Y2^vii—Au1—Y1^viii	70.46 (3)	Au1^xiv—Y2—Au1^x	106.57 (7)
Y2^i—Au1—Y1^ix	71.210 (16)	Au1^i—Y2—Au1^xv	92.91 (5)
Y2^ii—Au1—Y1^ix	71.210 (16)	Au1^ii—Y2—Au1^xv	149.78 (3)
Au1^iii—Au1—Y1^ix	114.894 (12)	Au1^xiii—Y2—Au1^xv	106.57 (7)
Y2^iv—Au1—Y1^ix	70.46 (3)	Au1^xiv—Y2—Au1^xv	59.16 (4)
Y2^v—Au1—Y1^ix	138.60 (4)	Au1^x—Y2—Au1^xv	78.34 (7)
Y2^vi—Au1—Y1^ix	70.46 (3)	Au1^i—Y2—Y1^xxii	55.77 (3)
Y2^vii—Au1—Y1^ix	138.60 (4)	Au1^ii—Y2—Y1^xxii	97.87 (6)
Y1^viii—Au1—Y1^ix	130.21 (2)	Au1^xiii—Y2—Y1^xxii	96.79 (4)
Au1^x—Y1—Au1^xi	180.000 (7)	Au1^xiv—Y2—Y1^xxii	55.39 (2)
Au1^x—Y1—Au1^xii	90.0	Au1^x—Y2—Y1^xxii	154.21 (5)
Au1^xi—Y1—Au1^xii	90.0	Au1^xv—Y2—Y1^xxii	102.37 (5)
Au1^x—Y1—Au1^iii	90.0	Au1^i—Y2—Y1^xxiii	97.87 (6)
Au1^xi—Y1—Au1^iii	90.0	Au1^ii—Y2—Y1^xxiii	55.77 (3)
Au1^xii—Y1—Au1^iii	180.0	Au1^xiii—Y2—Y1^xxiii	55.39 (2)
Au1^x—Y1—Y2^xvi	126.98 (3)	Au1^xiv—Y2—Y1^xxiii	96.79 (4)
Au1^xi—Y1—Y2^xvi	53.02 (3)	Au1^x—Y2—Y1^xxiii	102.37 (5)
Au1^xii—Y1—Y2^xvi	54.15 (4)	Au1^xv—Y2—Y1^xxiii	154.21 (5)
Au1^iii—Y1—Y2^xvi	125.85 (4)	Y1^xxii—Y2—Y1^xxiii	65.81 (5)
Au1^x—Y1—Y2^vii	53.02 (3)	Au1^i—Y2—Y1^xxiv	55.77 (3)
Au1^xi—Y1—Y2^vii	126.98 (3)	Au1^ii—Y2—Y1^xxiv	97.87 (6)
Au1^xii—Y1—Y2^vii	125.85 (4)	Au1^xiii—Y2—Y1^xxiv	154.21 (5)
Au1^iii—Y1—Y2^vii	54.15 (4)	Au1^xiv—Y2—Y1^xxiv	102.37 (5)
Y2^xvi—Y1—Y2^vii	180.00 (3)	Au1^x—Y2—Y1^xxiv	96.79 (4)
Au1^x—Y1—Y2^xvii	54.15 (4)	Au1^xv—Y2—Y1^xxiv	55.39 (2)
Au1^xi—Y1—Y2^xvii	125.85 (4)	Y1^xxii—Y2—Y1^xxiv	104.78 (5)
Au1^xii—Y1—Y2^xvii	53.02 (3)	Y1^xxiii—Y2—Y1^xxiv	147.71 (7)
Au1^iii—Y1—Y2^xvii	126.98 (3)	Au1^i—Y2—Y1^viii	97.87 (6)
Y2^xvi—Y1—Y2^xvii	107.16 (2)	Au1^ii—Y2—Y1^viii	55.77 (3)
Y2^vii—Y1—Y2^xvii	72.84 (2)	Au1^xiii—Y2—Y1^viii	102.37 (5)
Au1^x—Y1—Y2^xviii	125.85 (4)	Au1^xiv—Y2—Y1^viii	154.21 (5)
Au1^xi—Y1—Y2^xviii	54.15 (4)	Au1^x—Y2—Y1^viii	55.39 (2)
Au1^xii—Y1—Y2^xviii	126.98 (3)	Au1^xv—Y2—Y1^viii	96.79 (4)
Au1^iii—Y1—Y2^xviii	53.02 (3)	Y1^xxii—Y2—Y1^viii	147.71 (7)
Y2^xvi—Y1—Y2^xviii	72.84 (2)	Y1^xxiii—Y2—Y1^viii	104.78 (5)
Y2^vii—Y1—Y2^xviii	107.16 (2)	Y1^xxiv—Y2—Y1^viii	65.81 (5)
Y2^xvii—Y1—Y2^xviii	180.0	Au1^i—Y2—Y2^xvii	139.92 (4)
Au1^x—Y1—Y2^xix	126.98 (3)	Au1^ii—Y2—Y2^xvii	139.92 (4)
Au1^xi—Y1—Y2^xix	53.02 (3)	Au1^xiii—Y2—Y2^xvii	53.29 (4)
Au1^xii—Y1—Y2^xix	54.15 (4)	Au1^xiv—Y2—Y2^xvii	53.29 (4)
Au1^iii—Y1—Y2^xix	125.85 (4)	Au1^x—Y2—Y2^xvii	53.29 (4)
Y2^xvi—Y1—Y2^xix	65.81 (5)	Au1^xv—Y2—Y2^xvii	53.29 (4)
Y2^vii—Y1—Y2^xix	114.19 (5)	Y1^xxii—Y2—Y2^xvii	106.14 (3)
Y2^xvii—Y1—Y2^xix	72.84 (2)	Y1^xxiii—Y2—Y2^xvii	106.14 (3)
Y2^xviii—Y1—Y2^xix	107.16 (2)	Y1^xxiv—Y2—Y2^xvii	106.14 (3)
Au1^x—Y1—Y2^v	53.02 (3)	Y1^viii—Y2—Y2^xvii	106.14 (3)
Au1^xi—Y1—Y2^v	126.98 (3)	Au1^i—Y2—Y2^xxv	130.08 (4)
Au1^xii—Y1—Y2^v	125.85 (4)	Au1^ii—Y2—Y2^xxv	49.92 (4)
Au1^iii—Y1—Y2^v	54.15 (4)	Au1^xiii—Y2—Y2^xxv	50.83 (3)
Y2^xvi—Y1—Y2^v	114.19 (5)	Au1^xiv—Y2—Y2^xxv	129.17 (3)
Y2^vii—Y1—Y2^v	65.81 (5)	Au1^x—Y2—Y2^xxv	50.83 (3)
Y2^xvii—Y1—Y2^v	107.16 (2)	Au1^xv—Y2—Y2^xxv	129.17 (3)
Y2^xviii—Y1—Y2^v	72.84 (2)	Y1^xxii—Y2—Y2^xxv	122.90 (2)
Y2^xix—Y1—Y2^v	180.0	Y1^xxiii—Y2—Y2^xxv	57.10 (3)
Au1^x—Y1—Y2^xx	54.15 (4)	Y1^xxiv—Y2—Y2^xxv	122.90 (3)
Au1^xi—Y1—Y2^xx	125.85 (4)	Y1^viii—Y2—Y2^xxv	57.10 (2)
Au1^xii—Y1—Y2^xx	53.02 (3)	Y2^xvii—Y2—Y2^xxv	90.0

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

(Y2Au) diyttrium gold

Crystal data

Y2Au	Dx = 7.962 Mg m^−3 Dm = 7.962 Mg m^−3 Dm measured by not measured
Mr = 374.79	Mo Kα radiation, λ = 0.71073 Å
Orthorhombic, Pnma	Cell parameters from 584 reflections
a = 7.115 (3) Å	θ = 4.6–27.7°
b = 4.933 (2) Å	µ = 83.29 mm^−1
c = 8.908 (4) Å	T = 293 K
V = 312.7 (2) Å^3	Irregularly shaped, metallic silver
Z = 4	0.12 × 0.08 × 0.04 mm
F(000) = 628

Data collection

Bruker SMART CCD area-detector diffractometer	345 independent reflections
Radiation source: fine-focus sealed tube	299 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.039
ϕ and ω scans	θmax = 26.0°, θmin = 3.7°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −8→8
Tmin = 0.036, Tmax = 0.135	k = −6→5
1619 measured reflections	l = −7→10

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)] = 0.026	Secondary atom site location: difference Fourier map
wR(F^2) = 0.058	w = 1/[σ^2(Fo^2) + (0.0321P)^2] where P = (Fo^2 + 2Fc^2)/3
S = 1.07	(Δ/σ)max < 0.001
345 reflections	Δρmax = 1.76 e Å^−3
20 parameters	Δρmin = −2.14 e Å^−3

Special details

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 (Ų)

	x	y	z	Uiso*/Ueq
Au1	0.24296 (8)	0.2500	0.39987 (6)	0.0107 (2)
Y1	0.1474 (2)	0.2500	0.08075 (15)	0.0100 (3)
Y2	0.01605 (19)	0.2500	0.67592 (15)	0.0104 (4)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Au1	0.0135 (3)	0.0082 (3)	0.0105 (3)	0.000	−0.0005 (2)	0.000
Y1	0.0135 (8)	0.0059 (7)	0.0107 (6)	0.000	0.0001 (6)	0.000
Y2	0.0113 (7)	0.0088 (7)	0.0111 (7)	0.000	0.0007 (5)	0.000

Geometric parameters (Å, º)

Au1—Y1^i	2.883 (2)	Y1—Au1^viii	3.0477 (12)
Au1—Y1	2.9228 (18)	Y1—Y2^i	3.480 (2)
Au1—Y2	2.9417 (18)	Y1—Y2^v	3.4833 (17)
Au1—Y1^ii	3.0478 (13)	Y1—Y2^iv	3.4833 (17)
Au1—Y1^iii	3.0478 (13)	Y2—Au1^iv	3.1521 (13)
Au1—Y2^iv	3.1521 (13)	Y2—Au1^v	3.1521 (13)
Au1—Y2^v	3.1521 (13)	Y2—Y1^vi	3.480 (2)
Y1—Au1^vi	2.883 (2)	Y2—Y1^v	3.4833 (17)
Y1—Au1^vii	3.0477 (13)	Y2—Y1^iv	3.4833 (17)
Y1^i—Au1—Y1	106.89 (4)	Au1^viii—Y1—Y1^x	51.20 (3)
Y1^i—Au1—Y2	119.86 (5)	Y2^i—Y1—Y1^x	100.34 (6)
Y1—Au1—Y2	133.25 (5)	Y2^v—Y1—Y1^x	64.03 (4)
Y1^i—Au1—Y1^ii	73.31 (4)	Y2^iv—Y1—Y1^x	123.23 (7)
Y1—Au1—Y1^ii	125.01 (3)	Y2^viii—Y1—Y1^x	90.72 (4)
Y2—Au1—Y1^ii	72.46 (4)	Y2^vii—Y1—Y1^x	169.28 (7)
Y1^i—Au1—Y1^iii	73.31 (4)	Y1^ix—Y1—Y1^x	88.25 (7)
Y1—Au1—Y1^iii	125.01 (3)	Au1^vi—Y1—Y2^xi	78.91 (4)
Y2—Au1—Y1^iii	72.46 (4)	Au1—Y1—Y2^xi	178.93 (6)
Y1^ii—Au1—Y1^iii	108.05 (5)	Au1^vii—Y1—Y2^xi	63.41 (3)
Y1^i—Au1—Y2^iv	126.62 (3)	Au1^viii—Y1—Y2^xi	63.41 (3)
Y1—Au1—Y2^iv	69.86 (3)	Y2^i—Y1—Y2^xi	63.45 (4)
Y2—Au1—Y2^iv	81.84 (4)	Y2^v—Y1—Y2^xi	121.24 (4)
Y1^ii—Au1—Y2^iv	153.66 (4)	Y2^iv—Y1—Y2^xi	121.24 (4)
Y1^iii—Au1—Y2^iv	68.26 (4)	Y2^viii—Y1—Y2^xi	113.67 (4)
Y1^i—Au1—Y2^v	126.62 (3)	Y2^vii—Y1—Y2^xi	113.67 (4)
Y1—Au1—Y2^v	69.86 (3)	Y1^ix—Y1—Y2^xi	57.21 (4)
Y2—Au1—Y2^v	81.84 (4)	Y1^x—Y1—Y2^xi	57.21 (4)
Y1^ii—Au1—Y2^v	68.26 (4)	Au1—Y2—Au1^iv	98.16 (4)
Y1^iii—Au1—Y2^v	153.66 (4)	Au1—Y2—Au1^v	98.16 (4)
Y2^iv—Au1—Y2^v	102.98 (5)	Au1^iv—Y2—Au1^v	102.98 (5)
Y1^i—Au1—Y2^vii	63.80 (3)	Au1—Y2—Y1^vi	82.21 (5)
Y1—Au1—Y2^vii	64.70 (4)	Au1^iv—Y2—Y1^vi	54.45 (3)
Y2—Au1—Y2^vii	136.34 (2)	Au1^v—Y2—Y1^vi	54.45 (3)
Y1^ii—Au1—Y2^vii	136.41 (4)	Au1—Y2—Y1^v	134.70 (3)
Y1^iii—Au1—Y2^vii	67.49 (4)	Au1^iv—Y2—Y1^v	119.48 (5)
Y2^iv—Au1—Y2^vii	67.93 (3)	Au1^v—Y2—Y1^v	51.98 (3)
Y2^v—Au1—Y2^vii	134.01 (3)	Y1^vi—Y2—Y1^v	99.04 (4)
Y1^i—Au1—Y2^viii	63.80 (3)	Au1—Y2—Y1^iv	134.70 (3)
Y1—Au1—Y2^viii	64.70 (3)	Au1^iv—Y2—Y1^iv	51.98 (3)
Y2—Au1—Y2^viii	136.34 (2)	Au1^v—Y2—Y1^iv	119.48 (5)
Y1^ii—Au1—Y2^viii	67.49 (4)	Y1^vi—Y2—Y1^iv	99.04 (4)
Y1^iii—Au1—Y2^viii	136.41 (4)	Y1^v—Y2—Y1^iv	90.16 (6)
Y2^iv—Au1—Y2^viii	134.01 (3)	Au1—Y2—Y1^ii	55.16 (3)
Y2^v—Au1—Y2^viii	67.93 (3)	Au1^iv—Y2—Y1^ii	152.78 (5)
Y2^vii—Au1—Y2^viii	86.31 (4)	Au1^v—Y2—Y1^ii	78.41 (4)
Au1^vi—Y1—Au1	100.02 (4)	Y1^vi—Y2—Y1^ii	110.64 (4)
Au1^vi—Y1—Au1^vii	106.69 (4)	Y1^v—Y2—Y1^ii	83.19 (3)
Au1—Y1—Au1^vii	117.04 (3)	Y1^iv—Y2—Y1^ii	150.23 (5)
Au1^vi—Y1—Au1^viii	106.69 (4)	Au1—Y2—Y1^iii	55.16 (3)
Au1—Y1—Au1^viii	117.04 (3)	Au1^iv—Y2—Y1^iii	78.41 (4)
Au1^vii—Y1—Au1^viii	108.05 (5)	Au1^v—Y2—Y1^iii	152.78 (5)
Au1^vi—Y1—Y2^i	142.36 (5)	Y1^vi—Y2—Y1^iii	110.64 (4)
Au1—Y1—Y2^i	117.62 (6)	Y1^v—Y2—Y1^iii	150.23 (5)
Au1^vii—Y1—Y2^i	57.29 (3)	Y1^iv—Y2—Y1^iii	83.19 (3)
Au1^viii—Y1—Y2^i	57.29 (3)	Y1^ii—Y2—Y1^iii	88.31 (5)
Au1^vi—Y1—Y2^v	68.25 (3)	Au1—Y2—Au1^ii	101.62 (4)
Au1—Y1—Y2^v	58.17 (3)	Au1^iv—Y2—Au1^ii	158.71 (5)
Au1^vii—Y1—Y2^v	170.92 (4)	Au1^v—Y2—Au1^ii	82.03 (3)
Au1^viii—Y1—Y2^v	80.87 (4)	Y1^vi—Y2—Au1^ii	136.22 (2)
Y2^i—Y1—Y2^v	131.34 (3)	Y1^v—Y2—Au1^ii	47.95 (3)
Au1^vi—Y1—Y2^iv	68.25 (3)	Y1^iv—Y2—Au1^ii	107.39 (5)
Au1—Y1—Y2^iv	58.17 (3)	Y1^ii—Y2—Au1^ii	48.27 (3)
Au1^vii—Y1—Y2^iv	80.87 (4)	Y1^iii—Y2—Au1^ii	106.69 (5)
Au1^viii—Y1—Y2^iv	170.92 (4)	Au1—Y2—Au1^iii	101.62 (4)
Y2^i—Y1—Y2^iv	131.34 (3)	Au1^iv—Y2—Au1^iii	82.03 (3)
Y2^v—Y1—Y2^iv	90.16 (5)	Au1^v—Y2—Au1^iii	158.71 (5)
Au1^vi—Y1—Y2^viii	131.36 (3)	Y1^vi—Y2—Au1^iii	136.22 (2)
Au1—Y1—Y2^viii	67.03 (3)	Y1^v—Y2—Au1^iii	107.39 (5)
Au1^vii—Y1—Y2^viii	121.14 (5)	Y1^iv—Y2—Au1^iii	47.95 (3)
Au1^viii—Y1—Y2^viii	52.39 (3)	Y1^ii—Y2—Au1^iii	106.69 (5)
Y2^i—Y1—Y2^viii	69.36 (4)	Y1^iii—Y2—Au1^iii	48.27 (3)
Y2^v—Y1—Y2^viii	65.39 (3)	Au1^ii—Y2—Au1^iii	86.31 (4)
Y2^iv—Y1—Y2^viii	124.75 (5)	Au1—Y2—Y1^xii	132.18 (6)
Au1^vi—Y1—Y2^vii	131.36 (3)	Au1^iv—Y2—Y1^xii	110.73 (3)
Au1—Y1—Y2^vii	67.03 (3)	Au1^v—Y2—Y1^xii	110.73 (3)
Au1^vii—Y1—Y2^vii	52.39 (3)	Y1^vi—Y2—Y1^xii	145.60 (6)
Au1^viii—Y1—Y2^vii	121.14 (5)	Y1^v—Y2—Y1^xii	58.76 (4)
Y2^i—Y1—Y2^vii	69.36 (4)	Y1^iv—Y2—Y1^xii	58.76 (4)
Y2^v—Y1—Y2^vii	124.75 (5)	Y1^ii—Y2—Y1^xii	93.56 (4)
Y2^iv—Y1—Y2^vii	65.39 (3)	Y1^iii—Y2—Y1^xii	93.56 (4)
Y2^viii—Y1—Y2^vii	88.31 (5)	Au1^ii—Y2—Y1^xii	49.10 (3)
Au1^vi—Y1—Y1^ix	55.49 (4)	Au1^iii—Y2—Y1^xii	49.10 (3)
Au1—Y1—Y1^ix	122.19 (5)	Au1—Y2—Y2^xiii	77.06 (4)
Au1^vii—Y1—Y1^ix	51.20 (3)	Au1^iv—Y2—Y2^xiii	128.51 (3)
Au1^viii—Y1—Y1^ix	120.02 (6)	Au1^v—Y2—Y2^xiii	128.51 (3)
Y2^i—Y1—Y1^ix	100.34 (6)	Y1^vi—Y2—Y2^xiii	159.28 (6)
Y2^v—Y1—Y1^ix	123.23 (7)	Y1^v—Y2—Y2^xiii	95.54 (5)
Y2^iv—Y1—Y1^ix	64.03 (4)	Y1^iv—Y2—Y2^xiii	95.54 (5)
Y2^viii—Y1—Y1^ix	169.28 (7)	Y1^ii—Y2—Y2^xiii	56.57 (3)
Y2^vii—Y1—Y1^ix	90.72 (4)	Y1^iii—Y2—Y2^xiii	56.57 (3)
Au1^vi—Y1—Y1^x	55.49 (4)	Au1^ii—Y2—Y2^xiii	50.34 (3)
Au1—Y1—Y1^x	122.19 (5)	Au1^iii—Y2—Y2^xiii	50.34 (3)
Au1^vii—Y1—Y1^x	120.02 (6)	Y1^xii—Y2—Y2^xiii	55.12 (5)

Symmetry codes: (i) x+1/2, y, −z+1/2; (ii) −x+1/2, −y+1, z+1/2; (iii) −x+1/2, −y, z+1/2; (iv) −x, −y, −z+1; (v) −x, −y+1, −z+1; (vi) x−1/2, y, −z+1/2; (vii) −x+1/2, −y, z−1/2; (viii) −x+1/2, −y+1, z−1/2; (ix) −x, −y, −z; (x) −x, −y+1, −z; (xi) x, y, z−1; (xii) x, y, z+1; (xiii) x+1/2, y, −z+3/2.