A new ternary compound with the BGa₈Ir₄ structure type in the Al–Au–Ir system

Following the recent determination of the Al₃AuIr structure, a new ternary phase has been identified in the Al–Au–Ir phase diagram. It has a chemical composition Al₉(Au;Ir)₄ with an apparently low gold content. Its crystal structure has been determined with single-crystal X-ray diffraction. The new compound crystallizes in the tetragonal crystal system and has been successfully solved in space group I4₁/acd (Pearson symbol tI104) with lattice parameters a = 8.6339 (2) and c = 21.8874 (7) Å. Atomic environments are described as well as similarities with the BGa₈Ir₄ compound.

Computing details

Data collection: APEX2 (Bruker, 2004); cell refinement: SAINT (Bruker, 2004); data reduction: SAINT; program(s) used to solve structure: SHELXL2014 (Sheldrick, 2014); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2014).

(I)

Crystal data

Al72Au2.50Ir29.50	Dx = 8.249 Mg m^−3
Mr = 8104.88	Mo Kα radiation, λ = 0.71073 Å
Tetragonal, I41/acd	Cell parameters from 9909 reflections
a = 8.6339 (2) Å	θ = 3.7–44.3°
c = 21.8874 (7) Å	µ = 66.45 mm^−1
V = 1631.58 (9) Å^3	T = 296 K
Z = 1	Platelet, black
F(000) = 3405	0.05 × 0.05 × 0.01 mm

Data collection

Bruker APEX-II QUAZAR CCD diffractometer	1177 reflections with I > 2σ(I)
Radiation source: micro sources	Rint = 0.064
ω scan	θmax = 44.3°, θmin = 3.8°
Absorption correction: multi-scan SADABS 2014/5	h = −16→16
Tmin = 0.274, Tmax = 0.749	k = −16→16
44132 measured reflections	l = −42→42
1629 independent reflections

Refinement

Refinement on F^2	0 restraints
Least-squares matrix: full	w = 1/[σ^2(Fo^2) + (0.0139P)^2 + 16.567P] where P = (Fo^2 + 2Fc^2)/3
R[F^2 > 2σ(F^2)] = 0.017	(Δ/σ)max = 0.002
wR(F^2) = 0.043	Δρmax = 4.05 e Å^−3
S = 1.13	Δρmin = −1.85 e Å^−3
1629 reflections	Extinction correction: SHELXL, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
35 parameters	Extinction coefficient: 0.000130 (10)

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

	x	y	z	Uiso*/Ueq	Occ. (<1)
Ir1	0.0000	0.2500	0.01467 (2)	0.00316 (4)	0.923 (4)
Au1	0.0000	0.2500	0.01467 (2)	0.00316 (4)	0.0782 (4)
Ir2	0.19858 (2)	0.44858 (2)	0.1250	0.00368 (3)	0.922 (4)
Au2	0.19858 (2)	0.44858 (2)	0.1250	0.00368 (3)	0.0781 (3)
Al1	0.04687 (12)	0.03071 (12)	0.31109 (4)	0.0063 (2)
Al2	0.27779 (12)	0.19958 (12)	0.19068 (5)	0.0068 (2)
Al3	0.0000	0.2500	0.1250	0.0060 (3)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Ir1	0.00365 (14)	0.00361 (13)	0.00224 (5)	0.00039 (3)	0.000	0.000
Au1	0.00365 (14)	0.00361 (13)	0.00224 (5)	0.00039 (3)	0.000	0.000
Ir2	0.00358 (4)	0.00358 (4)	0.00390 (5)	0.00009 (3)	0.00000 (3)	0.00000 (3)
Au2	0.00358 (4)	0.00358 (4)	0.00390 (5)	0.00009 (3)	0.00000 (3)	0.00000 (3)
Al1	0.0084 (4)	0.0049 (4)	0.0057 (4)	0.0003 (3)	0.0004 (3)	0.0012 (3)
Al2	0.0049 (4)	0.0091 (4)	0.0064 (4)	0.0003 (3)	−0.0010 (3)	−0.0015 (3)
Al3	0.0080 (4)	0.0080 (4)	0.0020 (6)	−0.0043 (5)	0.000	0.000

Geometric parameters (Å, º)

Ir1—Al3	2.4148 (1)	Al1—Ir1^xi	2.6589 (10)
Ir1—Al2^i	2.5481 (10)	Al1—Au1^xi	2.6589 (10)
Ir1—Al2^ii	2.5481 (10)	Al1—Al1^xii	2.726 (2)
Ir1—Al1^iii	2.5491 (10)	Al1—Al2^xiii	2.7431 (15)
Ir1—Al1^iv	2.5491 (10)	Al1—Al2^ix	2.7778 (15)
Ir1—Al2^iii	2.6262 (10)	Al1—Al2^xii	2.8160 (14)
Ir1—Al2^iv	2.6262 (10)	Al2—Au1^xiv	2.5481 (10)
Ir1—Al1^v	2.6589 (10)	Al2—Ir1^xiv	2.5481 (10)
Ir1—Al1^vi	2.6589 (10)	Al2—Au2^xv	2.6086 (10)
Ir2—Al3	2.4247 (1)	Al2—Ir2^xv	2.6086 (10)
Ir2—Al2^vii	2.6086 (10)	Al2—Ir1^iii	2.6262 (10)
Ir2—Al2^viii	2.6086 (10)	Al2—Au1^iii	2.6262 (10)
Ir2—Al1^ix	2.6113 (11)	Al2—Al1^xvi	2.7431 (15)
Ir2—Al1^ii	2.6113 (11)	Al2—Al1^ix	2.7778 (15)
Ir2—Al1^v	2.6364 (10)	Al2—Al2^ix	2.780 (2)
Ir2—Al1^x	2.6364 (10)	Al2—Al1^xii	2.8160 (14)
Ir2—Al2^iii	2.6751 (11)	Al3—Au1^iii	2.4148 (1)
Ir2—Al2	2.6751 (11)	Al3—Ir1^iii	2.4148 (1)
Al1—Au1^iii	2.5492 (10)	Al3—Au2^xvii	2.4247 (1)
Al1—Ir1^iii	2.5492 (10)	Al3—Ir2^xvii	2.4247 (1)
Al1—Au2^ix	2.6113 (11)	Al3—Al1^x	2.8274 (10)
Al1—Ir2^ix	2.6113 (11)	Al3—Al1^vi	2.8274 (10)
Al1—Au2^xi	2.6363 (10)	Al3—Al1^v	2.8274 (10)
Al1—Ir2^xi	2.6363 (10)	Al3—Al1^xii	2.8274 (10)
Al3—Ir1—Al2^i	129.46 (2)	Au2^ix—Al1—Al2^ix	59.43 (3)
Al3—Ir1—Al2^ii	129.46 (2)	Ir2^ix—Al1—Al2^ix	59.43 (3)
Al2^i—Ir1—Al2^ii	101.08 (5)	Au2^xi—Al1—Al2^ix	132.14 (5)
Al3—Ir1—Al1^iii	130.58 (2)	Ir2^xi—Al1—Al2^ix	132.14 (5)
Al2^i—Ir1—Al1^iii	65.12 (4)	Ir1^xi—Al1—Al2^ix	147.32 (4)
Al2^ii—Ir1—Al1^iii	66.04 (4)	Au1^xi—Al1—Al2^ix	147.32 (4)
Al3—Ir1—Al1^iv	130.58 (2)	Al1^xii—Al1—Al2^ix	98.59 (5)
Al2^i—Ir1—Al1^iv	66.04 (4)	Al2^xiii—Al1—Al2^ix	90.90 (4)
Al2^ii—Ir1—Al1^iv	65.12 (4)	Au1^iii—Al1—Al2^xii	128.89 (5)
Al1^iii—Ir1—Al1^iv	98.84 (5)	Ir1^iii—Al1—Al2^xii	128.89 (5)
Al3—Ir1—Al2^iii	68.16 (2)	Au2^ix—Al1—Al2^xii	57.31 (3)
Al2^i—Ir1—Al2^iii	153.61 (4)	Ir2^ix—Al1—Al2^xii	57.31 (3)
Al2^ii—Ir1—Al2^iii	64.99 (4)	Au2^xi—Al1—Al2^xii	112.74 (4)
Al1^iii—Ir1—Al2^iii	88.51 (3)	Ir2^xi—Al1—Al2^xii	112.74 (4)
Al1^iv—Ir1—Al2^iii	120.67 (3)	Ir1^xi—Al1—Al2^xii	57.24 (3)
Al3—Ir1—Al2^iv	68.16 (2)	Au1^xi—Al1—Al2^xii	57.24 (3)
Al2^i—Ir1—Al2^iv	64.99 (4)	Al1^xii—Al1—Al2^xii	81.32 (4)
Al2^ii—Ir1—Al2^iv	153.61 (4)	Al2^xiii—Al1—Al2^xii	167.09 (5)
Al1^iii—Ir1—Al2^iv	120.67 (3)	Al2^ix—Al1—Al2^xii	101.88 (3)
Al1^iv—Ir1—Al2^iv	88.51 (3)	Au1^xiv—Al2—Ir1^xiv	0.000 (4)
Al2^iii—Ir1—Al2^iv	136.31 (4)	Au1^xiv—Al2—Au2^xv	115.68 (4)
Al3—Ir1—Al1^v	67.54 (2)	Ir1^xiv—Al2—Au2^xv	115.68 (4)
Al2^i—Ir1—Al1^v	106.50 (4)	Au1^xiv—Al2—Ir2^xv	115.68 (4)
Al2^ii—Ir1—Al1^v	101.64 (3)	Ir1^xiv—Al2—Ir2^xv	115.68 (4)
Al1^iii—Ir1—Al1^v	161.75 (2)	Au2^xv—Al2—Ir2^xv	0.000 (2)
Al1^iv—Ir1—Al1^v	63.09 (4)	Au1^xiv—Al2—Ir1^iii	115.01 (4)
Al2^iii—Ir1—Al1^v	98.51 (3)	Ir1^xiv—Al2—Ir1^iii	115.01 (4)
Al2^iv—Ir1—Al1^v	64.39 (3)	Au2^xv—Al2—Ir1^iii	114.47 (4)
Al3—Ir1—Al1^vi	67.54 (2)	Ir2^xv—Al2—Ir1^iii	114.47 (4)
Al2^i—Ir1—Al1^vi	101.64 (3)	Au1^xiv—Al2—Au1^iii	115.01 (4)
Al2^ii—Ir1—Al1^vi	106.50 (4)	Ir1^xiv—Al2—Au1^iii	115.01 (4)
Al1^iii—Ir1—Al1^vi	63.09 (4)	Au2^xv—Al2—Au1^iii	114.47 (4)
Al1^iv—Ir1—Al1^vi	161.75 (2)	Ir2^xv—Al2—Au1^iii	114.47 (4)
Al2^iii—Ir1—Al1^vi	64.39 (3)	Ir1^iii—Al2—Au1^iii	0.000 (5)
Al2^iv—Ir1—Al1^vi	98.51 (3)	Au1^xiv—Al2—Ir2	113.37 (4)
Al1^v—Ir1—Al1^vi	135.07 (4)	Ir1^xiv—Al2—Ir2	113.37 (4)
Al3—Ir2—Al2^vii	130.00 (2)	Au2^xv—Al2—Ir2	113.04 (4)
Al3—Ir2—Al2^viii	130.00 (2)	Ir2^xv—Al2—Ir2	113.04 (4)
Al2^vii—Ir2—Al2^viii	100.01 (5)	Ir1^iii—Al2—Ir2	80.40 (3)
Al3—Ir2—Al1^ix	130.06 (2)	Au1^iii—Al2—Ir2	80.40 (3)
Al2^vii—Ir2—Al1^ix	65.29 (3)	Au1^xiv—Al2—Al1^xvi	57.46 (3)
Al2^viii—Ir2—Al1^ix	65.84 (3)	Ir1^xiv—Al2—Al1^xvi	57.46 (3)
Al3—Ir2—Al1^ii	130.06 (2)	Au2^xv—Al2—Al1^xvi	58.96 (3)
Al2^vii—Ir2—Al1^ii	65.84 (3)	Ir2^xv—Al2—Al1^xvi	58.96 (3)
Al2^viii—Ir2—Al1^ii	65.29 (3)	Ir1^iii—Al2—Al1^xvi	150.09 (5)
Al1^ix—Ir2—Al1^ii	99.88 (4)	Au1^iii—Al2—Al1^xvi	150.09 (5)
Al3—Ir2—Al1^v	67.78 (2)	Ir2—Al2—Al1^xvi	129.50 (5)
Al2^vii—Ir2—Al1^v	159.91 (3)	Au1^xiv—Al2—Al1^ix	57.00 (3)
Al2^viii—Ir2—Al1^v	63.06 (3)	Ir1^xiv—Al2—Al1^ix	57.00 (3)
Al1^ix—Ir2—Al1^v	96.48 (4)	Au2^xv—Al2—Al1^ix	130.25 (4)
Al1^ii—Ir2—Al1^v	111.95 (3)	Ir2^xv—Al2—Al1^ix	130.25 (4)
Al3—Ir2—Al1^x	67.78 (2)	Ir1^iii—Al2—Al1^ix	111.34 (4)
Al2^vii—Ir2—Al1^x	63.06 (3)	Au1^iii—Al2—Al1^ix	111.34 (4)
Al2^viii—Ir2—Al1^x	159.91 (3)	Ir2—Al2—Al1^ix	57.19 (3)
Al1^ix—Ir2—Al1^x	111.95 (3)	Al1^xvi—Al2—Al1^ix	89.07 (4)
Al1^ii—Ir2—Al1^x	96.48 (4)	Au1^xiv—Al2—Al2^ix	58.86 (4)
Al1^v—Ir2—Al1^x	135.56 (4)	Ir1^xiv—Al2—Al2^ix	58.86 (4)
Al3—Ir2—Al2^iii	67.20 (2)	Au2^xv—Al2—Al2^ix	142.03 (6)
Al2^vii—Ir2—Al2^iii	98.43 (4)	Ir2^xv—Al2—Al2^ix	142.03 (6)
Al2^viii—Ir2—Al2^iii	110.58 (3)	Ir1^iii—Al2—Al2^ix	56.15 (4)
Al1^ix—Ir2—Al2^iii	161.22 (3)	Au1^iii—Al2—Al2^ix	56.15 (4)
Al1^ii—Ir2—Al2^iii	63.38 (3)	Ir2—Al2—Al2^ix	101.89 (5)
Al1^v—Ir2—Al2^iii	97.85 (3)	Al1^xvi—Al2—Al2^ix	109.01 (6)
Al1^x—Ir2—Al2^iii	64.56 (3)	Al1^ix—Al2—Al2^ix	81.06 (5)
Al3—Ir2—Al2	67.20 (2)	Au1^xiv—Al2—Al1^xii	131.49 (5)
Al2^vii—Ir2—Al2	110.58 (3)	Ir1^xiv—Al2—Al1^xii	131.49 (5)
Al2^viii—Ir2—Al2	98.43 (4)	Au2^xv—Al2—Al1^xii	57.40 (3)
Al1^ix—Ir2—Al2	63.38 (3)	Ir2^xv—Al2—Al1^xii	57.40 (3)
Al1^ii—Ir2—Al2	161.22 (3)	Ir1^iii—Al2—Al1^xii	58.37 (3)
Al1^v—Ir2—Al2	64.56 (3)	Au1^iii—Al2—Al1^xii	58.37 (3)
Al1^x—Ir2—Al2	97.85 (3)	Ir2—Al2—Al1^xii	112.27 (4)
Al2^iii—Ir2—Al2	134.40 (4)	Al1^xvi—Al2—Al1^xii	102.95 (4)
Au1^iii—Al1—Ir1^iii	0.000 (4)	Al1^ix—Al2—Al1^xii	167.85 (5)
Au1^iii—Al1—Au2^ix	115.54 (4)	Al2^ix—Al2—Al1^xii	96.42 (5)
Ir1^iii—Al1—Au2^ix	115.54 (4)	Ir1—Al3—Au1^iii	180.0
Au1^iii—Al1—Ir2^ix	115.54 (4)	Ir1—Al3—Ir1^iii	180.0
Ir1^iii—Al1—Ir2^ix	115.54 (4)	Au1^iii—Al3—Ir1^iii	0.0
Au2^ix—Al1—Ir2^ix	0.000 (6)	Ir1—Al3—Ir2	90.0
Au1^iii—Al1—Au2^xi	114.67 (4)	Au1^iii—Al3—Ir2	90.0
Ir1^iii—Al1—Au2^xi	114.67 (4)	Ir1^iii—Al3—Ir2	90.0
Au2^ix—Al1—Au2^xi	114.25 (4)	Ir1—Al3—Au2^xvii	90.0
Ir2^ix—Al1—Au2^xi	114.25 (4)	Au1^iii—Al3—Au2^xvii	90.0
Au1^iii—Al1—Ir2^xi	114.67 (4)	Ir1^iii—Al3—Au2^xvii	90.0
Ir1^iii—Al1—Ir2^xi	114.67 (4)	Ir2—Al3—Au2^xvii	180.0
Au2^ix—Al1—Ir2^xi	114.25 (4)	Ir1—Al3—Ir2^xvii	90.0
Ir2^ix—Al1—Ir2^xi	114.25 (4)	Au1^iii—Al3—Ir2^xvii	90.0
Au2^xi—Al1—Ir2^xi	0.000 (1)	Ir1^iii—Al3—Ir2^xvii	90.0
Au1^iii—Al1—Ir1^xi	113.85 (4)	Ir2—Al3—Ir2^xvii	180.0
Ir1^iii—Al1—Ir1^xi	113.85 (4)	Au2^xvii—Al3—Ir2^xvii	0.000 (6)
Au2^ix—Al1—Ir1^xi	113.28 (4)	Ir1—Al3—Al1^x	119.65 (2)
Ir2^ix—Al1—Ir1^xi	113.28 (4)	Au1^iii—Al3—Al1^x	60.35 (2)
Au2^xi—Al1—Ir1^xi	80.52 (3)	Ir1^iii—Al3—Al1^x	60.35 (2)
Ir2^xi—Al1—Ir1^xi	80.52 (3)	Ir2—Al3—Al1^x	59.67 (2)
Au1^iii—Al1—Au1^xi	113.85 (4)	Au2^xvii—Al3—Al1^x	120.33 (2)
Ir1^iii—Al1—Au1^xi	113.85 (4)	Ir2^xvii—Al3—Al1^x	120.33 (2)
Au2^ix—Al1—Au1^xi	113.28 (4)	Ir1—Al3—Al1^vi	60.35 (2)
Ir2^ix—Al1—Au1^xi	113.28 (4)	Au1^iii—Al3—Al1^vi	119.65 (2)
Au2^xi—Al1—Au1^xi	80.52 (3)	Ir1^iii—Al3—Al1^vi	119.65 (2)
Ir2^xi—Al1—Au1^xi	80.52 (3)	Ir2—Al3—Al1^vi	120.33 (2)
Ir1^xi—Al1—Au1^xi	0.000 (5)	Au2^xvii—Al3—Al1^vi	59.67 (2)
Au1^iii—Al1—Al1^xii	60.42 (4)	Ir2^xvii—Al3—Al1^vi	59.67 (2)
Ir1^iii—Al1—Al1^xii	60.42 (4)	Al1^x—Al3—Al1^vi	89.97 (4)
Au2^ix—Al1—Al1^xii	122.60 (2)	Ir1—Al3—Al1^v	60.35 (2)
Ir2^ix—Al1—Al1^xii	122.60 (2)	Au1^iii—Al3—Al1^v	119.65 (2)
Au2^xi—Al1—Al1^xii	117.91 (3)	Ir1^iii—Al3—Al1^v	119.65 (2)
Ir2^xi—Al1—Al1^xii	117.91 (3)	Ir2—Al3—Al1^v	59.67 (2)
Ir1^xi—Al1—Al1^xii	56.49 (4)	Au2^xvii—Al3—Al1^v	120.33 (2)
Au1^xi—Al1—Al1^xii	56.49 (4)	Ir2^xvii—Al3—Al1^v	120.33 (2)
Au1^iii—Al1—Al2^xiii	57.42 (3)	Al1^x—Al3—Al1^v	119.35 (4)
Ir1^iii—Al1—Al2^xiii	57.42 (3)	Al1^vi—Al3—Al1^v	120.69 (4)
Au2^ix—Al1—Al2^xiii	133.16 (5)	Ir1—Al3—Al1^xii	119.65 (2)
Ir2^ix—Al1—Al2^xiii	133.16 (5)	Au1^iii—Al3—Al1^xii	60.35 (2)
Au2^xi—Al1—Al2^xiii	57.97 (3)	Ir1^iii—Al3—Al1^xii	60.35 (2)
Ir2^xi—Al1—Al2^xiii	57.97 (3)	Ir2—Al3—Al1^xii	120.33 (2)
Ir1^xi—Al1—Al2^xiii	110.50 (4)	Au2^xvii—Al3—Al1^xii	59.67 (2)
Au1^xi—Al1—Al2^xiii	110.50 (4)	Ir2^xvii—Al3—Al1^xii	59.67 (2)
Al1^xii—Al1—Al2^xiii	95.13 (4)	Al1^x—Al3—Al1^xii	120.69 (4)
Au1^iii—Al1—Al2^ix	56.96 (3)	Al1^vi—Al3—Al1^xii	119.35 (4)
Ir1^iii—Al1—Al2^ix	56.96 (3)	Al1^v—Al3—Al1^xii	89.97 (4)

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