Redetermination of Dy₃Ni from single-crystal X-ray data

The classification of the title compound, tridysprosium nickel, into the Fe₃C (or Al₃Ni) structure type has been deduced from powder X-ray diffraction data with lattice parameters reported in a previous study [Lemaire & Paccard (1967). Bull. Soc. Fr. Mineral. Cristallogr. 40, 311–315]. The current re-investigation of Dy₃Ni based on single-crystal X-ray data revealed atomic positional parameters and anisotropic displacement parameters with high precision. The asymmetric unit consists of two Dy and one Ni atoms. One Dy atom has site symmetry .m. (Wyckoff position 4c) and is surrounded by twelve Dy and three Ni atoms. The other Dy atom (site symmetry 1, 8d) has eleven Dy and three Ni atoms as neighbours, forming a distorted Frank–Kasper polyhedron. The coordination polyhedron of the Ni atom (.m., 4c) is a tricapped trigonal prism formed by nine Dy atoms.

Related literature

For a previous crystallographic investigation of the title compound, see: Lemaire & Paccard (1967). For the Fe₃C structure, see: Hendricks (1930), and for the Al₃Ni structure, see: Bradley & Taylor (1937). For the Dy–Ni phase diagram, see: Zheng & Wang (1982). For magnetic properties of Dy₃Ni, see: Talik et al. (1996), and for magnetic properties of Dy₃Co, see: Baranov et al. (1995). For isotypic compounds, see: Tsvyashchenko (1986); Romaka et al. (2011); Buschow & van der Goot (1969); Givord & Lemaire (1971). For structure refinements of other compounds in the Dy–Ni system, see: Levytskyy et al. (2012a,b).

Experimental

Crystal data

• Dy₃Ni

• M_r = 546.21

• Orthorhombic, P n m a

• a = 6.863 (3) Å

• b = 9.553 (3) Å

• c = 6.302 (2) Å

• V = 413.2 (3) ų

• Z = 4

• Mo Kα radiation

• μ = 57.86 mm⁻¹

• T = 293 K

• 0.14 × 0.11 × 0.10 mm

Data collection

• Stoe IPDS II diffractometer

• Absorption correction: numerical (X-RED; Stoe & Cie, 2009) T_min = 0.007, T_max = 0.026

• 973 measured reflections

• 582 independent reflections

• 447 reflections with I > 2σ(I)

• R_int = 0.042

Refinement

• R[F² > 2σ(F²)] = 0.042

• wR(F²) = 0.052

• S = 1.12

• 582 reflections

• 23 parameters

• Δρ_max = 2.82 e Å⁻³

• Δρ_min = −2.65 e Å⁻³

Data collection: X-AREA (Stoe & Cie, 2009); cell refinement: X-AREA; data reduction: X-AREA; program(s) used to solve structure: SIR2011 (Burla et al., 2012); program(s) used to refine structure: SHELXL2013 (Sheldrick, 2008) and WinGX (Farrugia, 2012); molecular graphics: DIAMOND (Brandenburg, 2006); software used to prepare material for publication: publCIF (Westrip, 2010).

Supporting information

S1. Comment

Lattice parameters for RE₃Ni compounds with RE = Y, La, Pr, Nd, Sm, Gd–Tm, have been determined and their crystal structures reported to be isotypic with the Fe₃C (or Al₃Ni) type structure which includes also Dy₃Ni (Lemaire & Paccard, 1967). According to the phase diagram of the Dy–Ni system (Zheng & Wang, 1982), Dy₃Ni is stable below 1035 K and is formed by the peritectic reaction: Dy + L → Dy₃Ni.

Similar isotypic RE₃Co compounds were also reported (Buschow & van der Goot, 1969) for RE = Y, La, Pr, Nd, Sm, Gd–Er. Lu₃Co has been prepared by Givord & Lemaire (1971), Lu₃Ni by Romaka et al. (2011). Tsvyashchenko (1986) synthesized Yb₃Co and Yb₃Ni at high pressure. According to Tsvyashchenko (1986), Yb₃Co adopts the Fe₃C type structure and Yb₃Ni the Al₃Ni structure type. On the other hand, Lemaire & Paccard (1967) claimed the RE₃Ni compounds to have the same structure as the RE₃Co compounds. To clarify the confusion with the assigned structure types, we have studied literature data for the Fe₃C (Hendricks, 1930) and the Al₃Ni (Bradley & Taylor, 1937) prototype structures, concluding that Al₃Ni and Fe₃C are isotypic. In accordance with the majority in literature, we will use the Fe₃C structure type for classification as it has been reported earlier.

Recently, two binary compounds of the Dy–Ni system have been redetermined using single-crystal X-ray data (Levytskyy et al., 2012a,b). Here we present the results of the single-crystal X-ray analysis of Dy₃Ni. Details of the crystal structure have not been investigated before, and only isotypism with the Fe₃C was reported together with lattice parameters (Lemaire & Paccard, 1967).

The structure of Dy₃Ni is characterized by formation of trigonal prisms of Dy atoms with Ni atom enclosed in the centre. A view of the crystal structure of Dy₃Ni is shown in Fig. 1. The value of the displacement parameter U₂₂ for the Ni atom displays a high anisotropy in the b direction which may have an influence on some physical properties of the compound. Magnetic properties of Dy₃Ni were reported by Talik et al. (1996) and generally confirm this assumption which is also valid for the isotypic Dy₃Co (Baranov et al., 1995).

In Fig. 2 the ac projection of the unit cell and the coordination polyhedra for all atom types in Dy₃Ni are shown. The coordination number for Dy1 (site symmetry .m., Wyckoff site 4 c) is 15 with bonding to 12 Dy and 3 Ni atoms. The coordination number for Dy2 (site symmetry 1, Wyckoff site 8 d) is 14, resulting in a distorted Frank–Kasper polyhedron defined by 11 Dy and 3 Ni atoms. The coordination number for Ni (site symmetry .m., Wyckoff site 4 c) is 9, resulting in a slightly distorted tricapped trigonal prism made up of 9 Dy atoms.

The analysis of interatomic distances shows a slight decrease of some Dy–Ni distances. This feature is in good agreement with the observed Ho–Co distances for previously reported Ho₃Co (Buschow & van der Goot, 1969). The explanation of this fact may be deduced from an electronic band structure calculation.

Related literature

For a previous crystallographic investigation of the title compound, see: Lemaire & Paccard (1967). For the Fe₃C structure, see: Hendricks (1930), and for the Al₃Ni structure, see: Bradley & Taylor (1937). For the Dy–Ni phase diagram, see: Zheng & Wang (1982). For magnetic properties of Dy₃Ni, see: Talik et al. (1996), and for magnetic properties of Dy₃Co, see: Baranov et al. (1995). For isotypic compounds, see: Tsvyashchenko (1986); Romaka et al. (2011); Buschow & van der Goot (1969); Givord & Lemaire (1971). For structure refinements of other compounds in the Dy–Ni system, see: Levytskyy et al. (2012a,b).

S2. Experimental

The sample was prepared from powdered commercially available pure elements: sublimed bulk pieces of dysprosium metal with a claimed purity of 99.99 at.% (Alfa Aesar, Johnson Matthey) and electrolytic nickel (99.99% pure) pieces (Aldrich). A mixture of the powders was compacted into a pellet. It was arc-melted under an argon atmosphere on a water-cooled copper hearth. The alloy button (~1 g) was turned over and remelted three times to improve homogeneity. Subsequently, the sample was annealed in an evacuated silica tube under an argon atmosphere for four weeks at 870 K. Shiny metallic gray plate-like crystals were isolated mechanically with a help of microscope by crushing the sample.

S3. Refinement

The atomic positions found from the direct methods structure solution were in good agreement with those from the Fe₃C structure type (Hendricks, 1930) and were used as starting point for the structure refinement. The highest Fourier difference peak of 2.82 e Å^-3 is at (0.0340 0.75 0.1598) and 1.36 Å away from the Dy2 atom. The deepest hole of -2.65 e Å^-3 is at (0.0358 0.25 0.0220) and 1.01 Å away from the Ni atom.

Computing details

Data collection: X-AREA (Stoe & Cie, 2009); cell refinement: X-AREA (Stoe & Cie, 2009); data reduction: X-AREA (Stoe & Cie, 2009); program(s) used to solve structure: SIR2011 (Burla et al., 2012); program(s) used to refine structure: SHELXL2013 (Sheldrick, 2008) and WinGX (Farrugia, 2012); molecular graphics: DIAMOND (Brandenburg, 2006); software used to prepare material for publication: publCIF (Westrip, 2010).

Figures

	Fig. 1. Perspective view of the crystal structure of Dy3Ni. The unit cell and coordination trigonal prisms for Ni atoms are emphasized. The stacking edge of these prisms is marked by red colour. Atoms are represented by their anisotropic displacement ellipsoids at the 99.9% probability level.
	Fig. 2. The ac projection of the unit cell and coordination polyhedra for all types of atoms in the Dy3Ni structure.

Tridysprosium nickel

Crystal data

Dy3Ni	Dx = 8.781 Mg m^−3
Mr = 546.21	Mo Kα radiation, λ = 0.71073 Å
Orthorhombic, Pnma	Cell parameters from 2575 reflections
a = 6.863 (3) Å	θ = 3.7–29.5°
b = 9.553 (3) Å	µ = 57.86 mm^−1
c = 6.302 (2) Å	T = 293 K
V = 413.2 (3) Å^3	Block, metallic gray
Z = 4	0.14 × 0.11 × 0.10 mm
F(000) = 904

Data collection

Stoe IPDS II diffractometer	447 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.042
ω scans	θmax = 29.6°, θmin = 3.9°
Absorption correction: numerical (X-RED; Stoe & Cie, 2009)	h = 0→9
Tmin = 0.007, Tmax = 0.026	k = 0→12
973 measured reflections	l = −8→8
582 independent reflections

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.042	w = 1/[σ^2(Fo^2) + (0.0141P)^2] where P = (Fo^2 + 2Fc^2)/3
wR(F^2) = 0.052	(Δ/σ)max < 0.001
S = 1.12	Δρmax = 2.82 e Å^−3
582 reflections	Δρmin = −2.65 e Å^−3
23 parameters	Extinction correction: SHELXL2013 (Sheldrick, 2008), Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
0 restraints	Extinction coefficient: 0.00030 (10)

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
Dy1	0.17975 (10)	0.06439 (6)	0.17745 (9)	0.01479 (17)
Dy2	0.03218 (14)	0.2500	0.63694 (13)	0.0147 (2)
Ni	0.3917 (4)	0.2500	0.4477 (4)	0.0197 (5)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Dy1	0.0150 (3)	0.0151 (3)	0.0143 (2)	0.0001 (3)	0.0003 (3)	−0.0004 (2)
Dy2	0.0158 (5)	0.0144 (4)	0.0138 (4)	0.000	0.0014 (3)	0.000
Ni	0.0131 (12)	0.0268 (14)	0.0192 (11)	0.000	0.0003 (10)	0.000

Geometric parameters (Å, º)

Dy1—Ni^i	2.770 (2)	Dy2—Dy1^xii	3.5361 (12)
Dy1—Ni	2.856 (2)	Dy2—Dy1^vi	3.5433 (12)
Dy1—Ni^ii	3.3700 (15)	Dy2—Dy1^viii	3.5944 (14)
Dy1—Dy1^iii	3.5174 (11)	Dy2—Dy1^i	3.5944 (14)
Dy1—Dy1^iv	3.5174 (11)	Dy2—Dy1^xiii	3.6047 (12)
Dy1—Dy2^v	3.5361 (12)	Dy2—Dy1^iii	3.6047 (12)
Dy1—Dy2	3.5433 (12)	Dy2—Dy2^xiv	3.7156 (15)
Dy1—Dy1^vi	3.5462 (16)	Dy2—Dy2^xi	3.7156 (15)
Dy1—Dy1^vii	3.5502 (15)	Ni—Dy1^x	2.770 (2)
Dy1—Dy1^viii	3.5512 (15)	Ni—Dy1^ix	2.770 (2)
Dy1—Dy1^ix	3.5512 (15)	Ni—Dy2^xiv	2.790 (3)
Dy1—Dy2^x	3.5944 (14)	Ni—Dy1^vi	2.856 (2)
Dy2—Ni	2.740 (3)	Ni—Dy1^xiii	3.3700 (15)
Dy2—Ni^xi	2.790 (3)	Ni—Dy1^iii	3.3700 (15)
Dy2—Dy1^v	3.5361 (12)
Ni^i—Dy1—Ni	97.80 (5)	Dy1—Dy2—Dy1^vi	60.06 (3)
Ni^i—Dy1—Ni^ii	110.14 (3)	Ni—Dy2—Dy1^viii	111.46 (6)
Ni—Dy1—Ni^ii	152.06 (4)	Ni^xi—Dy2—Dy1^viii	106.54 (6)
Ni^i—Dy1—Dy1^iii	132.42 (6)	Dy1^v—Dy2—Dy1^viii	59.11 (2)
Ni—Dy1—Dy1^iii	62.83 (4)	Dy1^xii—Dy2—Dy1^viii	108.94 (3)
Ni^ii—Dy1—Dy1^iii	96.49 (5)	Dy1—Dy2—Dy1^viii	59.67 (3)
Ni^i—Dy1—Dy1^iv	99.46 (5)	Dy1^vi—Dy2—Dy1^viii	89.35 (3)
Ni—Dy1—Dy1^iv	127.71 (7)	Ni—Dy2—Dy1^i	111.46 (6)
Ni^ii—Dy1—Dy1^iv	48.95 (4)	Ni^xi—Dy2—Dy1^i	106.54 (6)
Dy1^iii—Dy1—Dy1^iv	127.23 (4)	Dy1^v—Dy2—Dy1^i	108.94 (3)
Ni^i—Dy1—Dy2^v	110.13 (6)	Dy1^xii—Dy2—Dy1^i	59.11 (2)
Ni—Dy1—Dy2^v	122.64 (5)	Dy1—Dy2—Dy1^i	89.35 (3)
Ni^ii—Dy1—Dy2^v	47.57 (5)	Dy1^vi—Dy2—Dy1^i	59.67 (3)
Dy1^iii—Dy1—Dy2^v	61.27 (3)	Dy1^viii—Dy2—Dy1^i	59.12 (3)
Dy1^iv—Dy1—Dy2^v	96.43 (3)	Ni—Dy2—Dy1^xiii	62.42 (3)
Ni^i—Dy1—Dy2	73.05 (5)	Ni^xi—Dy2—Dy1^xiii	97.07 (4)
Ni—Dy1—Dy2	49.28 (6)	Dy1^v—Dy2—Dy1^xiii	155.48 (3)
Ni^ii—Dy1—Dy2	139.07 (5)	Dy1^xii—Dy2—Dy1^xiii	59.64 (3)
Dy1^iii—Dy1—Dy2	61.40 (2)	Dy1—Dy2—Dy1^xiii	108.55 (3)
Dy1^iv—Dy1—Dy2	170.23 (3)	Dy1^vi—Dy2—Dy1^xiii	58.947 (18)
Dy2^v—Dy1—Dy2	92.13 (2)	Dy1^viii—Dy2—Dy1^xiii	144.99 (2)
Ni^i—Dy1—Dy1^vi	50.21 (4)	Dy1^i—Dy2—Dy1^xiii	89.83 (3)
Ni—Dy1—Dy1^vi	51.63 (4)	Ni—Dy2—Dy1^iii	62.42 (3)
Ni^ii—Dy1—Dy1^vi	153.03 (4)	Ni^xi—Dy2—Dy1^iii	97.07 (4)
Dy1^iii—Dy1—Dy1^vi	110.47 (2)	Dy1^v—Dy2—Dy1^iii	59.64 (3)
Dy1^iv—Dy1—Dy1^vi	110.47 (2)	Dy1^xii—Dy2—Dy1^iii	155.48 (3)
Dy2^v—Dy1—Dy1^vi	148.141 (19)	Dy1—Dy2—Dy1^iii	58.947 (18)
Dy2—Dy1—Dy1^vi	59.972 (15)	Dy1^vi—Dy2—Dy1^iii	108.55 (3)
Ni^i—Dy1—Dy1^vii	63.03 (5)	Dy1^viii—Dy2—Dy1^iii	89.83 (3)
Ni—Dy1—Dy1^vii	160.83 (5)	Dy1^i—Dy2—Dy1^iii	144.99 (2)
Ni^ii—Dy1—Dy1^vii	47.11 (5)	Dy1^xiii—Dy2—Dy1^iii	112.85 (4)
Dy1^iii—Dy1—Dy1^vii	129.32 (4)	Ni—Dy2—Dy2^xiv	48.35 (6)
Dy1^iv—Dy1—Dy1^vii	60.32 (3)	Ni^xi—Dy2—Dy2^xiv	87.67 (7)
Dy2^v—Dy1—Dy1^vii	68.17 (3)	Dy1^v—Dy2—Dy2^xiv	104.66 (3)
Dy2—Dy1—Dy1^vii	119.32 (4)	Dy1^xii—Dy2—Dy2^xiv	104.66 (3)
Dy1^vi—Dy1—Dy1^vii	110.28 (2)	Dy1—Dy2—Dy2^xiv	92.83 (3)
Ni^i—Dy1—Dy1^viii	51.95 (5)	Dy1^vi—Dy2—Dy2^xiv	92.83 (3)
Ni—Dy1—Dy1^viii	109.78 (6)	Dy1^viii—Dy2—Dy2^xiv	146.39 (2)
Ni^ii—Dy1—Dy1^viii	88.29 (5)	Dy1^i—Dy2—Dy2^xiv	146.39 (2)
Dy1^iii—Dy1—Dy1^viii	91.96 (3)	Dy1^xiii—Dy2—Dy2^xiv	57.75 (2)
Dy1^iv—Dy1—Dy1^viii	119.71 (3)	Dy1^iii—Dy2—Dy2^xiv	57.75 (2)
Dy2^v—Dy1—Dy1^viii	61.14 (2)	Ni—Dy2—Dy2^xi	176.75 (7)
Dy2—Dy1—Dy1^viii	60.88 (2)	Ni^xi—Dy2—Dy2^xi	47.22 (6)
Dy1^vi—Dy1—Dy1^viii	90.0	Dy1^v—Dy2—Dy2^xi	59.55 (2)
Dy1^vii—Dy1—Dy1^viii	59.38 (3)	Dy1^xii—Dy2—Dy2^xi	59.55 (2)
Ni^i—Dy1—Dy1^ix	139.72 (4)	Dy1—Dy2—Dy2^xi	125.27 (3)
Ni—Dy1—Dy1^ix	49.80 (5)	Dy1^vi—Dy2—Dy2^xi	125.27 (3)
Ni^ii—Dy1—Dy1^ix	104.55 (5)	Dy1^viii—Dy2—Dy2^xi	65.79 (3)
Dy1^iii—Dy1—Dy1^ix	60.29 (3)	Dy1^i—Dy2—Dy2^xi	65.79 (3)
Dy1^iv—Dy1—Dy1^ix	88.04 (3)	Dy1^xiii—Dy2—Dy2^xi	118.64 (2)
Dy2^v—Dy1—Dy1^ix	108.20 (2)	Dy1^iii—Dy2—Dy2^xi	118.64 (2)
Dy2—Dy1—Dy1^ix	93.77 (3)	Dy2^xiv—Dy2—Dy2^xi	134.90 (5)
Dy1^vi—Dy1—Dy1^ix	90.0	Dy2—Ni—Dy1^x	140.04 (4)
Dy1^vii—Dy1—Dy1^ix	146.49 (3)	Dy2—Ni—Dy1^ix	140.04 (4)
Dy1^viii—Dy1—Dy1^ix	150.16 (4)	Dy1^x—Ni—Dy1^ix	79.59 (8)
Ni^i—Dy1—Dy2^x	90.43 (6)	Dy2—Ni—Dy2^xiv	84.43 (7)
Ni—Dy1—Dy2^x	71.33 (6)	Dy1^x—Ni—Dy2^xiv	91.17 (8)
Ni^ii—Dy1—Dy2^x	107.50 (5)	Dy1^ix—Ni—Dy2^xiv	91.17 (8)
Dy1^iii—Dy1—Dy2^x	118.81 (4)	Dy2—Ni—Dy1	78.53 (7)
Dy1^iv—Dy1—Dy2^x	59.62 (2)	Dy1^x—Ni—Dy1	126.22 (9)
Dy2^v—Dy1—Dy2^x	151.42 (2)	Dy1^ix—Ni—Dy1	78.25 (5)
Dy2—Dy1—Dy2^x	113.33 (3)	Dy2^xiv—Ni—Dy1	137.35 (5)
Dy1^vi—Dy1—Dy2^x	60.442 (16)	Dy2—Ni—Dy1^vi	78.53 (7)
Dy1^vii—Dy1—Dy2^x	106.94 (4)	Dy1^x—Ni—Dy1^vi	78.25 (5)
Dy1^viii—Dy1—Dy2^x	142.39 (2)	Dy1^ix—Ni—Dy1^vi	126.22 (9)
Dy1^ix—Dy1—Dy2^x	59.45 (3)	Dy2^xiv—Ni—Dy1^vi	137.35 (5)
Ni—Dy2—Ni3^xi	136.02 (9)	Dy1—Ni—Dy1^vi	76.74 (7)
Ni—Dy2—Dy1^v	120.95 (2)	Dy2—Ni—Dy1^xiii	71.46 (5)
Ni^xi—Dy2—Dy1^v	63.09 (3)	Dy1^x—Ni—Dy1^xiii	69.86 (3)
Ni—Dy2—Dy1^xii	120.95 (2)	Dy1^ix—Ni—Dy1^xiii	142.80 (9)
Ni^xi—Dy2—Dy1^xii	63.09 (3)	Dy2^xiv—Ni—Dy1^xiii	69.34 (4)
Dy1^v—Dy2—Dy1^xii	116.28 (4)	Dy1—Ni—Dy1^xiii	137.33 (9)
Ni—Dy2—Dy1	52.19 (4)	Dy1^vi—Ni—Dy1^xiii	68.22 (3)
Ni^xi—Dy2—Dy1	149.959 (16)	Dy2—Ni—Dy1^iii	71.46 (5)
Dy1^v—Dy2—Dy1	87.87 (3)	Dy1^x—Ni—Dy1^iii	142.80 (9)
Dy1^xii—Dy2—Dy1	144.38 (2)	Dy1^ix—Ni—Dy1^iii	69.86 (3)
Ni—Dy2—Dy1^vi	52.19 (4)	Dy2^xiv—Ni—Dy1^iii	69.34 (4)
Ni^xi—Dy2—Dy1^vi	149.959 (16)	Dy1—Ni—Dy1^iii	68.22 (3)
Dy1^v—Dy2—Dy1^vi	144.38 (2)	Dy1^vi—Ni—Dy1^iii	137.33 (9)
Dy1^xii—Dy2—Dy1^vi	87.87 (2)	Dy1^xiii—Ni—Dy1^iii	126.05 (8)

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