Ca₄IrO₆, Ca₃MgIrO₆ and Ca₃ZnIrO₆

Single crystals of tetracalcium iridium hexaoxide, Ca₄IrO₆, tricalcium magnesium iridium hexaoxide, Ca₃MgIrO₆, and tricalcium zinc iridium hexaoxide, Ca₃ZnIrO₆, were prepared via high-temperature flux growth and structurally characterized by single-crystal X-ray diffraction. The three compounds are isostructural and adopt the K₄CdCl₆ structure type, comprised of chains of alternating face-shared [CaO₆], [MgO₆] or [ZnO₆] trigonal prisms and [IrO₆] octahedra, surrounded by columns of Ca²⁺ ions.

S1. Comment

Ternary and quaternary transition metal oxides belonging to a family of pseudo-one-dimensional oxides derived from the K₄CdCl₆ structure type (Bergerhoff & Schmitz-Dumont, 1959), with the general formula A₃A'BO₆, have attracted widespread attention in recent years. This interest can be attributed to their compositional flexibility (Smith & zur Loye, 2000), their low dimensionality, the intriguing magnetic properties exhibited by members of this family of oxides (Nguyen & zur Loye, 1995) and their ability to stabilize high oxidation states (Carlson & Stacy, 1992). While there are several powder X-ray diffraction studies for these materials, only a few calcium iridates with this structure type, for example Ca₃CuIrO₆ (Tomaszewska & Müller-Buschbaum, 1993), Ca₃NaIrO₆ (Claridge et al., 1997), and Ca_3.75Ni_0.25IrO₆ (Claridge et al., 1998), have been characterized by single-crystal X-ray diffraction.

In an effort to synthesize novel compounds with the general formula A₃A'BO₆, exploratory work has been carried out in the calcium-(metal)-iridium-oxygen phase space, which has resulted in the preparation of single crystals of Ca₄IrO₆, (I), Ca₃MgIrO₆, (II) and Ca₃ZnIrO₆, (III) (nominal compositions). Small dark rhombohedral-shaped crystals of (I), (II) and (III) were grown from a eutectic halide flux of CaCl₂, KCl and NaCl at high temperatures. While the structure of (I) has previously been determined by powder X-ray diffraction (Sarkozy et al., 1974; Segal et al., 1996), (II) and (III) have not been structurally characterized prior to the present work. The occurrence of zinc in the trigonal prismatic coordination is notable in (III), since the common coordination environment in oxides is tetrahedral (Greenwood & Earnshaw, 1989). \sch

The structure of the title compounds consists of infinite one-dimensional chains of alternating face-shared [A'O₆] trigonal prisms and rhombohedrally elongated [BO₆] octahedra running parallel to the c axis (Fig. 1). These chains are surrounded by six spiral columns of distorted square [CaO₈] antiprisms, and these Ca²⁺ columns are in turn surrounded by three one-dimensional chains (Fig. 2). Located just off the threefold axis, the Ca—O square antiprisms are highly distorted [Ca—O 2.371 (2)–2.699 (3) Å for (I), 2.359 (2)–2.689 (2) Å for (II) and 2.349 (3)–2.675 (3) Å for (III)].

The [IrO₆] octahedra are regular, with Ir—O distances ranging from 2.012 (3) to 2.020 (2) Å, in agreement with other octahedral Ir⁴⁺ compounds, e.g. 1.98 (1) Å in Ca₃SrIrO₆ (Segal et al., 1996) and 2.024 (3) Å in Ca_3.5Ni_0.5IrO₆ (Claridge et al., 1998). The CaO₆ [in (I)], MgO₆ [in (II)] or ZnO₆ [in (III)] trigonal prisms are also regular (Tables 1–3), although they exhibit a significant twisting distortion from an ideal eclipsed conformation [ϕ = 19.4 (2), 15.8 (2) and 17.7 (2)° for (I)-(III), respectively]. These distances are also typical for M—O bond lengths for elements in trigonal prismatic coordination in this structure type, e.g. 2.20 (1) Å in Sr₃MgIrO₆ (Nguyen & zur Loye, 1995) and 2.199 (4) Å in Sr₃ZnPtO₆ (Lampe-Önnerud & zur Loye, 1996).

One would expect that the substitution of either Mg or Zn for Ca would affect the lattice parameters and the unit cell size. Since the ionic radii for these elements in sixfold coordination are 0.72 Å for Mg²⁺, 0.74 Å for Zn²⁺ and 1.00 Å for Ca²⁺ (Shannon, 1976), we would expect a decrease in the overall unit cell volume. Two recent studies of the size effect of the A' cation using a series of rare earths (Layland et al., 1998; Smith & zur Loye, 2000) indicated that both the unit cell volume and the ratio of c/a tend to decrease when smaller cations are substituted for larger ones. In this particular case, we find that indeed the unit cell volume decreases, as expected, and the c/a ratio also decreases. The unit cell volume change, however, is not the same for Mg and Zn, as one might have expected from their very similar ionic radii. Sr analogues of this structure type exhibit a similar trend (Segal et al., 1996; Núñez et al., 1997). There seems to be a difference between main group (filled d shell) elements and either transition metals or alkaline earth metals. In the study by Layland et al. (1998), In also did not follow the expected trend.

Related literature

For related literature, see: Bergerhoff & Schmitz-Dumont (1959); Carlson & Stacy (1992); Claridge et al. (1997, 1998); Greenwood & Earnshaw (1989); Lampe-Önnerud & zur Loye (1996); Layland et al. (1998); Núñez et al. (1997); Nguyen & zur Loye (1995); Sarkozy et al. (1974); Segal et al. (1996); Shannon (1976); Smith & zur Loye (2000); Tomaszewska & Müller-Buschbaum (1993).

S2. Experimental

Single crystals of the title compounds were grown with a tenfold excess eutectic flux of CaCl₂, KCl and NaCl (all Fisher, reagent grade). Ca(OH)₂ (Mallinckrodt, reagent grade), either MgO (Alfa, 99.998%) or ZnO (Alfa, 99.998%), for (II) and (III), respectively, and Ir (Engelhard, 99.95%) were used as reagents. The starting materials were placed in covered alumina crucibles and heated in air at 1198 K for 24 h, and then cooled to 873 K at a rate of 15 K h^-1, at which point the furnace was shut off. The flux was dissolved with distilled water and dark rhombohedral crystals were isolated for analysis.

S3. Refinement

The patterns of systematic absences in the data confirmed a c glide operation, indicating the space groups R3c and R3c. Preliminary powder X-ray diffraction showed the compounds to be isostructural with K₄CdCl₆ (space group R3c). Therefore, the expected centrosymmetric space group was chosen and confirmed by the solution of the structures. Structure solution and refinement of compound (I) proceeded without incident, and all atomic positions were found to be fully occupied by the constituent atoms. However, refinement of compound (II) using a fully occupied Ca₃MgIrO₆ model resulted in an isotropic displacement parameter value of zero for the Mg atom in the trigonal prismatic site (Wyckoff symbol 6a). Previous reports of quaternary calcium iridium oxides have shown mixing of alkaline earth cations and the metal on the trigonal prismatic site (Claridge et al., 1998), and therefore this model was adopted for (II). The final refinement yielded site occupancy factors (SOF) of 0.662 (10) for Mg and 0.338 (10) for Ca on the 6a site. Both the SOF and anisotropic displacement parameters for these atoms could be refined simultaneously, subject to the constraints that the total SOF was equal to 1.0, and that the anisotropic displacement parameters for both atoms were set equal. Similar mixing on the trigonal prismatic site was also observed for compound (III). Values for the SOF of 50% Zn and 50% Ca on the trigonal prismatic site were obtained from refinement with isotropic displacement parameters. However, since even constrained simultaneous refinement of the SOF with the anisotropic displacement factors proved unstable, the SOF values were fixed at 0.5 Ca and 0.5 Zn before the final anisotropic refinement was completed. The largest difference peaks for the three compounds were 3.25 e Å^-3 for (I), 2.19 e Å^-3 for (II) and 4.57 e Å^-3 for (III), all located less than 0.8 Å from Ir.

Computing details

For all compounds, data collection: SMART (Bruker, 2000); cell refinement: SAINT+ (Bruker, 1998); data reduction: SAINT+; program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL (Sheldrick, 1997); software used to prepare material for publication: SHELXTL.

Figures

	Fig. 1. The [001] projection of Ca4IrO6.
	Fig. 2. The structure of a chain in Ca4IrO6 showing 80% probability displacement ellipsoids.

(I) Tetracalcium iridium hexaoxide

Crystal data

Ca4IrO6	Dx = 5.378 Mg m^−3
Mr = 448.52	Mo Kα radiation, λ = 0.71073 Å
Trigonal, R3c	Cell parameters from 1993 reflections
a = 9.3030 (5) Å	θ = 3.1–36.3°
c = 11.0864 (8) Å	µ = 27.77 mm^−1
V = 830.93 (9) Å^3	T = 293 K
Z = 6	Irregular, black
F(000) = 1230	0.08 × 0.06 × 0.04 mm

Data collection

Bruker SMART APEX CCD area-detector diffractometer	450 independent reflections
Radiation source: fine-focus sealed tube	408 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.026
ω scans	θmax = 36.3°, θmin = 4.4°
Absorption correction: multi-scan (SADABS; Bruker, 1997)	h = −10→14
Tmin = 0.112, Tmax = 0.168	k = −14→13
2592 measured reflections	l = −8→18

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)] = 0.024	w = 1/[σ^2(Fo^2) + (0.0428P)^2] where P = (Fo^2 + 2Fc^2)/3
wR(F^2) = 0.061	(Δ/σ)max < 0.001
S = 1.07	Δρmax = 3.25 e Å^−3
450 reflections	Δρmin = −3.59 e Å^−3
20 parameters	Extinction correction: SHELXL97 (Sheldrick, 1997), Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
0 restraints	Extinction coefficient: 0.00062 (14)

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
Ca1	−0.36207 (10)	0.0000	0.2500	0.00693 (17)
Ca2	1.0000	0.0000	0.2500	0.0122 (4)
Ir	1.0000	0.0000	0.0000	0.00359 (12)
O1	−0.1588 (3)	0.0285 (3)	0.1081 (2)	0.0098 (4)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Ca1	0.0070 (3)	0.0062 (3)	0.0073 (3)	0.00310 (17)	−0.00039 (13)	−0.0008 (3)
Ca2	0.0134 (6)	0.0134 (6)	0.0098 (8)	0.0067 (3)	0.000	0.000
Ir	0.00327 (13)	0.00327 (13)	0.00422 (16)	0.00164 (7)	0.000	0.000
O1	0.0090 (10)	0.0100 (10)	0.0119 (9)	0.0060 (9)	0.0053 (8)	−0.0003 (8)

Geometric parameters (Å, º)

Ca1—O1^i	2.371 (2)	Ca2—Ca1^xiv	3.3683 (9)
Ca1—O1	2.371 (2)	Ca2—Ca1^xiii	3.3683 (9)
Ca1—O1^ii	2.493 (2)	Ca2—Ca1^xv	3.3683 (9)
Ca1—O1^iii	2.493 (2)	Ca2—Ca1^xix	3.5032 (4)
Ca1—O1^iv	2.519 (2)	Ir—O1^xiv	2.020 (2)
Ca1—O1^v	2.519 (2)	Ir—O1^xx	2.020 (2)
Ca1—O1^vi	2.699 (3)	Ir—O1^xiii	2.020 (2)
Ca1—O1^vii	2.699 (3)	Ir—O1^xv	2.020 (2)
Ca1—Ir^viii	3.1164 (4)	Ir—O1^xxi	2.020 (2)
Ca1—Ir^ix	3.1165 (4)	Ir—O1^xxii	2.020 (2)
Ca1—Ca2^x	3.3683 (9)	Ir—Ca2^xxiii	2.7716 (2)
Ca1—Ca1^xi	3.5032 (4)	Ir—Ca1^xxiv	3.1164 (4)
Ca2—O1^xii	2.263 (2)	Ir—Ca1^xxv	3.1164 (4)
Ca2—O1^xiii	2.263 (2)	Ir—Ca1^xxvi	3.1164 (4)
Ca2—O1^xiv	2.263 (2)	Ir—Ca1^xxvii	3.1164 (4)
Ca2—O1^xv	2.263 (2)	O1—Ir^x	2.020 (2)
Ca2—O1^xvi	2.263 (2)	O1—Ca2^x	2.263 (2)
Ca2—O1^xvii	2.263 (2)	O1—Ca1^ii	2.493 (2)
Ca2—Ir	2.7716 (2)	O1—Ca1^xxviii	2.519 (2)
Ca2—Ir^xviii	2.7716 (2)	O1—Ca1^xi	2.699 (3)
O1^i—Ca1—O1	84.23 (12)	O1^xvii—Ca2—Ca1^xiii	105.53 (6)
O1^i—Ca1—O1^ii	94.09 (8)	Ir—Ca2—Ca1^xiii	90.0
O1—Ca1—O1^ii	74.60 (9)	Ir^xviii—Ca2—Ca1^xiii	90.0
O1^i—Ca1—O1^iii	74.59 (9)	Ca1^xiv—Ca2—Ca1^xiii	120.0
O1—Ca1—O1^iii	94.09 (8)	O1^xii—Ca2—Ca1^xv	105.53 (6)
O1^ii—Ca1—O1^iii	164.95 (12)	O1^xiii—Ca2—Ca1^xv	105.53 (6)
O1^i—Ca1—O1^iv	135.49 (5)	O1^xiv—Ca2—Ca1^xv	116.34 (6)
O1—Ca1—O1^iv	71.68 (10)	O1^xv—Ca2—Ca1^xv	44.65 (6)
O1^ii—Ca1—O1^iv	113.75 (8)	O1^xvi—Ca2—Ca1^xv	116.34 (6)
O1^iii—Ca1—O1^iv	70.59 (9)	O1^xvii—Ca2—Ca1^xv	44.65 (6)
O1^i—Ca1—O1^v	71.69 (10)	Ir—Ca2—Ca1^xv	90.0
O1—Ca1—O1^v	135.49 (5)	Ir^xviii—Ca2—Ca1^xv	90.0
O1^ii—Ca1—O1^v	70.59 (9)	Ca1^xiv—Ca2—Ca1^xv	120.0
O1^iii—Ca1—O1^v	113.75 (8)	Ca1^xiii—Ca2—Ca1^xv	120.0
O1^iv—Ca1—O1^v	148.80 (12)	O1^xii—Ca2—Ca1^xix	45.15 (6)
O1^i—Ca1—O1^vi	120.71 (4)	O1^xiii—Ca2—Ca1^xix	164.29 (6)
O1—Ca1—O1^vi	138.29 (8)	O1^xiv—Ca2—Ca1^xix	100.61 (6)
O1^ii—Ca1—O1^vi	129.47 (3)	O1^xv—Ca2—Ca1^xix	87.34 (6)
O1^iii—Ca1—O1^vi	65.56 (11)	O1^xvi—Ca2—Ca1^xix	104.03 (6)
O1^iv—Ca1—O1^vi	67.31 (9)	O1^xvii—Ca2—Ca1^xix	50.38 (6)
O1^v—Ca1—O1^vi	85.99 (7)	Ir—Ca2—Ca1^xix	121.832 (4)
O1^i—Ca1—O1^vii	138.29 (8)	Ir^xviii—Ca2—Ca1^xix	58.168 (4)
O1—Ca1—O1^vii	120.71 (4)	Ca1^xiv—Ca2—Ca1^xix	68.513 (14)
O1^ii—Ca1—O1^vii	65.56 (11)	Ca1^xiii—Ca2—Ca1^xix	147.889 (6)
O1^iii—Ca1—O1^vii	129.47 (3)	Ca1^xv—Ca2—Ca1^xix	61.266 (11)
O1^iv—Ca1—O1^vii	85.99 (7)	O1^xiv—Ir—O1^xx	180.00 (16)
O1^v—Ca1—O1^vii	67.31 (9)	O1^xiv—Ir—O1^xiii	88.40 (10)
O1^vi—Ca1—O1^vii	64.15 (11)	O1^xx—Ir—O1^xiii	91.60 (10)
O1^i—Ca1—Ir^viii	114.75 (6)	O1^xiv—Ir—O1^xv	88.40 (10)
O1—Ca1—Ir^viii	101.08 (6)	O1^xx—Ir—O1^xv	91.60 (10)
O1^ii—Ca1—Ir^viii	150.50 (6)	O1^xiii—Ir—O1^xv	88.40 (10)
O1^iii—Ca1—Ir^viii	40.31 (5)	O1^xiv—Ir—O1^xxi	91.60 (10)
O1^iv—Ca1—Ir^viii	40.28 (5)	O1^xx—Ir—O1^xxi	88.40 (10)
O1^v—Ca1—Ir^viii	122.79 (6)	O1^xiii—Ir—O1^xxi	180.00 (17)
O1^vi—Ca1—Ir^viii	39.84 (5)	O1^xv—Ir—O1^xxi	91.60 (10)
O1^vii—Ca1—Ir^viii	94.02 (6)	O1^xiv—Ir—O1^xxii	91.60 (10)
O1^i—Ca1—Ir^ix	101.08 (6)	O1^xx—Ir—O1^xxii	88.40 (10)
O1—Ca1—Ir^ix	114.75 (6)	O1^xiii—Ir—O1^xxii	91.60 (10)
O1^ii—Ca1—Ir^ix	40.31 (5)	O1^xv—Ir—O1^xxii	180.00 (14)
O1^iii—Ca1—Ir^ix	150.50 (6)	O1^xxi—Ir—O1^xxii	88.40 (10)
O1^iv—Ca1—Ir^ix	122.79 (6)	O1^xiv—Ir—Ca2	53.61 (7)
O1^v—Ca1—Ir^ix	40.28 (5)	O1^xx—Ir—Ca2	126.39 (7)
O1^vi—Ca1—Ir^ix	94.02 (6)	O1^xiii—Ir—Ca2	53.61 (7)
O1^vii—Ca1—Ir^ix	39.84 (5)	O1^xv—Ir—Ca2	53.61 (7)
Ir^viii—Ca1—Ir^ix	131.37 (3)	O1^xxi—Ir—Ca2	126.39 (7)
O1^i—Ca1—Ca2^x	42.12 (6)	O1^xxii—Ir—Ca2	126.39 (7)
O1—Ca1—Ca2^x	42.12 (6)	O1^xiv—Ir—Ca2^xxiii	126.39 (7)
O1^ii—Ca1—Ca2^x	82.48 (6)	O1^xx—Ir—Ca2^xxiii	53.61 (7)
O1^iii—Ca1—Ca2^x	82.48 (6)	O1^xiii—Ir—Ca2^xxiii	126.39 (7)
O1^iv—Ca1—Ca2^x	105.60 (6)	O1^xv—Ir—Ca2^xxiii	126.39 (7)
O1^v—Ca1—Ca2^x	105.60 (6)	O1^xxi—Ir—Ca2^xxiii	53.61 (7)
O1^vi—Ca1—Ca2^x	147.93 (5)	O1^xxii—Ir—Ca2^xxiii	53.61 (7)
O1^vii—Ca1—Ca2^x	147.93 (5)	Ca2—Ir—Ca2^xxiii	180.0
Ir^viii—Ca1—Ca2^x	114.313 (15)	O1^xiv—Ir—Ca1^xxiv	52.98 (7)
Ir^ix—Ca1—Ca2^x	114.315 (15)	O1^xx—Ir—Ca1^xxiv	127.02 (7)
O1^i—Ca1—Ca1^xi	85.73 (6)	O1^xiii—Ir—Ca1^xxiv	58.87 (7)
O1—Ca1—Ca1^xi	50.30 (6)	O1^xv—Ir—Ca1^xxiv	126.25 (7)
O1^ii—Ca1—Ca1^xi	124.69 (6)	O1^xxi—Ir—Ca1^xxiv	121.13 (7)
O1^iii—Ca1—Ca1^xi	45.97 (6)	O1^xxii—Ir—Ca1^xxiv	53.75 (7)
O1^iv—Ca1—Ca1^xi	50.04 (6)	Ca2—Ir—Ca1^xxiv	72.755 (3)
O1^v—Ca1—Ca1^xi	154.26 (5)	Ca2^xxiii—Ir—Ca1^xxiv	107.245 (3)
O1^vi—Ca1—Ca1^xi	95.50 (5)	O1^xiv—Ir—Ca1^xxv	127.02 (7)
O1^vii—Ca1—Ca1^xi	135.96 (5)	O1^xx—Ir—Ca1^xxv	52.98 (7)
Ir^viii—Ca1—Ca1^xi	55.800 (1)	O1^xiii—Ir—Ca1^xxv	121.13 (7)
Ir^ix—Ca1—Ca1^xi	163.325 (15)	O1^xv—Ir—Ca1^xxv	53.75 (7)
Ca2^x—Ca1—Ca1^xi	61.266 (11)	O1^xxi—Ir—Ca1^xxv	58.87 (7)
O1^xii—Ca2—O1^xiii	148.94 (12)	O1^xxii—Ir—Ca1^xxv	126.25 (7)
O1^xii—Ca2—O1^xiv	89.31 (12)	Ca2—Ir—Ca1^xxv	107.245 (3)
O1^xiii—Ca2—O1^xiv	76.97 (9)	Ca2^xxiii—Ir—Ca1^xxv	72.755 (3)
O1^xii—Ca2—O1^xv	127.33 (12)	Ca1^xxiv—Ir—Ca1^xxv	180.00 (3)
O1^xiii—Ca2—O1^xv	76.97 (9)	O1^xiv—Ir—Ca1^xxvi	53.75 (7)
O1^xiv—Ca2—O1^xv	76.97 (9)	O1^xx—Ir—Ca1^xxvi	126.25 (7)
O1^xii—Ca2—O1^xvi	76.97 (9)	O1^xiii—Ir—Ca1^xxvi	127.02 (7)
O1^xiii—Ca2—O1^xvi	89.31 (12)	O1^xv—Ir—Ca1^xxvi	121.13 (7)
O1^xiv—Ca2—O1^xvi	127.33 (12)	O1^xxi—Ir—Ca1^xxvi	52.98 (7)
O1^xv—Ca2—O1^xvi	148.94 (12)	O1^xxii—Ir—Ca1^xxvi	58.87 (7)
O1^xii—Ca2—O1^xvii	76.97 (9)	Ca2—Ir—Ca1^xxvi	107.245 (3)
O1^xiii—Ca2—O1^xvii	127.33 (12)	Ca2^xxiii—Ir—Ca1^xxvi	72.755 (3)
O1^xiv—Ca2—O1^xvii	148.94 (12)	Ca1^xxiv—Ir—Ca1^xxvi	68.396 (2)
O1^xv—Ca2—O1^xvii	89.31 (12)	Ca1^xxv—Ir—Ca1^xxvi	111.604 (2)
O1^xvi—Ca2—O1^xvii	76.97 (9)	O1^xiv—Ir—Ca1^xxvii	126.25 (7)
O1^xii—Ca2—Ir	134.06 (6)	O1^xx—Ir—Ca1^xxvii	53.75 (7)
O1^xiii—Ca2—Ir	45.94 (6)	O1^xiii—Ir—Ca1^xxvii	52.98 (7)
O1^xiv—Ca2—Ir	45.94 (6)	O1^xv—Ir—Ca1^xxvii	58.87 (7)
O1^xv—Ca2—Ir	45.94 (6)	O1^xxi—Ir—Ca1^xxvii	127.02 (7)
O1^xvi—Ca2—Ir	134.06 (6)	O1^xxii—Ir—Ca1^xxvii	121.13 (7)
O1^xvii—Ca2—Ir	134.06 (6)	Ca2—Ir—Ca1^xxvii	72.755 (3)
O1^xii—Ca2—Ir^xviii	45.94 (6)	Ca2^xxiii—Ir—Ca1^xxvii	107.245 (3)
O1^xiii—Ca2—Ir^xviii	134.06 (6)	Ca1^xxiv—Ir—Ca1^xxvii	111.604 (2)
O1^xiv—Ca2—Ir^xviii	134.06 (6)	Ca1^xxv—Ir—Ca1^xxvii	68.396 (2)
O1^xv—Ca2—Ir^xviii	134.06 (6)	Ca1^xxvi—Ir—Ca1^xxvii	180.00 (3)
O1^xvi—Ca2—Ir^xviii	45.94 (6)	Ir^x—O1—Ca2^x	80.45 (9)
O1^xvii—Ca2—Ir^xviii	45.94 (6)	Ir^x—O1—Ca1	166.86 (12)
Ir—Ca2—Ir^xviii	180.0	Ca2^x—O1—Ca1	93.23 (8)
O1^xii—Ca2—Ca1^xiv	44.65 (6)	Ir^x—O1—Ca1^ii	86.70 (9)
O1^xiii—Ca2—Ca1^xiv	116.34 (6)	Ca2^x—O1—Ca1^ii	94.79 (9)
O1^xiv—Ca2—Ca1^xiv	44.65 (6)	Ca1—O1—Ca1^ii	105.40 (9)
O1^xv—Ca2—Ca1^xiv	105.53 (6)	Ir^x—O1—Ca1^xxviii	85.98 (8)
O1^xvi—Ca2—Ca1^xiv	105.53 (6)	Ca2^x—O1—Ca1^xxviii	165.76 (11)
O1^xvii—Ca2—Ca1^xiv	116.34 (6)	Ca1—O1—Ca1^xxviii	99.16 (9)
Ir—Ca2—Ca1^xiv	90.0	Ca1^ii—O1—Ca1^xxviii	88.69 (8)
Ir^xviii—Ca2—Ca1^xiv	90.0	Ir^x—O1—Ca1^xi	81.29 (8)
O1^xii—Ca2—Ca1^xiii	116.34 (6)	Ca2^x—O1—Ca1^xi	89.39 (8)
O1^xiii—Ca2—Ca1^xiii	44.65 (6)	Ca1—O1—Ca1^xi	87.16 (8)
O1^xiv—Ca2—Ca1^xiii	105.53 (6)	Ca1^ii—O1—Ca1^xi	166.46 (10)
O1^xv—Ca2—Ca1^xiii	116.34 (6)	Ca1^xxviii—O1—Ca1^xi	84.27 (7)
O1^xvi—Ca2—Ca1^xiii	44.65 (6)

Symmetry codes: (i) x−y, −y, −z+1/2; (ii) −x−1/3, −y+1/3, −z+1/3; (iii) −x+y−2/3, y−1/3, z+1/6; (iv) −x−2/3, −x+y−1/3, −z+1/6; (v) −y−1/3, x−y+1/3, z+1/3; (vi) −y−2/3, −x−1/3, z+1/6; (vii) x−y−1/3, x+1/3, −z+1/3; (viii) y−2/3, x−4/3, −z+1/6; (ix) x−4/3, y+1/3, z+1/3; (x) x−1, y, z; (xi) y−1/3, −x+y−2/3, −z+1/3; (xii) −x+1, −x+y, −z+1/2; (xiii) −y+1, x−y, z; (xiv) −x+y+1, −x, z; (xv) x+1, y, z; (xvi) y+1, x, −z+1/2; (xvii) x−y+1, −y, −z+1/2; (xviii) y+1, x−1, −z+1/2; (xix) x−y+4/3, x+2/3, −z+2/3; (xx) x−y+1, x, −z; (xxi) y+1, −x+y, −z; (xxii) −x+1, −y, −z; (xxiii) −x+2, −y, −z; (xxiv) x−y+5/3, x+1/3, −z+1/3; (xxv) −x+y+1/3, −x−1/3, z−1/3; (xxvi) −y+4/3, x−y+2/3, z−1/3; (xxvii) y+2/3, −x+y−2/3, −z+1/3; (xxviii) −x+y−2/3, −x−1/3, z−1/3.

(II) Tricalcium magnesium iridium hexaoxide

Crystal data

Ca3.34Mg0.66IrO6	Dx = 5.303 Mg m^−3
Mr = 438.16	Mo Kα radiation, λ = 0.71073 Å
Trigonal, R3c	Cell parameters from 1830 reflections
a = 9.2876 (4) Å	θ = 3.1–33.1°
c = 11.0200 (8) Å	µ = 27.49 mm^−1
V = 823.23 (8) Å^3	T = 293 K
Z = 6	Rhombohedron, black
F(000) = 1198	0.10 × 0.06 × 0.05 mm

Data collection

Bruker SMART APEX CCD area-detector diffractometer	350 independent reflections
Radiation source: fine-focus sealed tube	326 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.023
ω scans	θmax = 33.1°, θmin = 4.4°
Absorption correction: multi-scan (SADABS; Bruker, 1997)	h = −9→14
Tmin = 0.104, Tmax = 0.137	k = −13→12
2382 measured reflections	l = −16→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)] = 0.015	Secondary atom site location: difference Fourier map
wR(F^2) = 0.034	w = 1/[σ^2(Fo^2) + (0.0203P)^2] where P = (Fo^2 + 2Fc^2)/3
S = 1.09	(Δ/σ)max < 0.001
350 reflections	Δρmax = 2.19 e Å^−3
20 parameters	Δρmin = −1.13 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	Occ. (<1)
Ca1	0.30466 (7)	0.3333	0.0833	0.00731 (13)
Ca2	0.0000	0.0000	0.7500	0.0047 (6)	0.338 (10)
Mg	0.0000	0.0000	0.7500	0.0047 (6)	0.66
Ir	0.0000	0.0000	1.0000	0.00436 (8)
O	0.1853 (2)	0.0275 (2)	1.10975 (16)	0.0110 (4)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Ca1	0.0065 (2)	0.0058 (3)	0.0094 (3)	0.00292 (15)	−0.00044 (11)	−0.0009 (2)
Ca2	0.0045 (7)	0.0045 (7)	0.0050 (9)	0.0023 (4)	0.000	0.000
Mg	0.0045 (7)	0.0045 (7)	0.0050 (9)	0.0023 (4)	0.000	0.000
Ir	0.00302 (9)	0.00302 (9)	0.00705 (11)	0.00151 (4)	0.000	0.000
O	0.0075 (9)	0.0114 (9)	0.0146 (8)	0.0051 (8)	−0.0058 (7)	−0.0012 (6)

Geometric parameters (Å, º)

Ca1—O^i	2.3590 (19)	Mg—O^xiii	2.2310 (19)
Ca1—O^ii	2.3591 (19)	Mg—O^xiv	2.231 (2)
Ca1—O^iii	2.4967 (19)	Mg—O^xv	2.2310 (19)
Ca1—O^iv	2.4967 (19)	Mg—O^xvi	2.2310 (19)
Ca1—O^v	2.5301 (19)	Mg—Ir	2.7550 (2)
Ca1—O^vi	2.5302 (19)	Mg—Ir^xvii	2.7550 (2)
Ca1—O^vii	2.689 (2)	Mg—Ca1^xviii	3.3621 (7)
Ca1—O^viii	2.689 (2)	Mg—Ca1^xix	3.3622 (7)
Ca1—Ir^ix	3.1103 (3)	Mg—Ca1^xx	3.3622 (7)
Ca1—Ir^iv	3.1103 (3)	Mg—Ca1^xxi	3.4934 (3)
Ca1—Ca2^x	3.3621 (7)	Ir—O^xv	2.0128 (18)
Ca1—Mg^x	3.3621 (7)	Ir—O	2.0128 (18)
Ca2—O^xi	2.2310 (19)	Ir—O^xvi	2.0128 (18)
Ca2—O^xii	2.231 (2)	Ir—O^xii	2.0128 (18)
Ca2—O^xiii	2.2310 (19)	Ir—O^xxii	2.0128 (18)
Ca2—O^xiv	2.231 (2)	Ir—O^xxiii	2.0128 (18)
Ca2—O^xv	2.2310 (19)	Ir—Mg^xv	2.7550 (2)
Ca2—O^xvi	2.2310 (19)	Ir—Ca2^xv	2.7550 (2)
Ca2—Ir	2.7550 (2)	Ir—Ca1^xxiv	3.1103 (3)
Ca2—Ir^xvii	2.7550 (2)	Ir—Ca1^xxv	3.1103 (3)
Ca2—Ca1^xviii	3.3621 (7)	O—Mg^xv	2.2310 (19)
Ca2—Ca1^xix	3.3622 (7)	O—Ca2^xv	2.2310 (19)
Ca2—Ca1^xx	3.3622 (7)	O—Ca1^ii	2.3591 (19)
Ca2—Ca1^xxi	3.4934 (3)	O—Ca1^xxiv	2.4967 (19)
Mg—O^xi	2.2310 (19)	O—Ca1^xxvi	2.5302 (19)
Mg—O^xii	2.231 (2)	O—Ca1^xxvii	2.6888 (19)
O^i—Ca1—O^ii	82.88 (10)	O^xii—Mg—O^xvi	77.30 (7)
O^i—Ca1—O^iii	74.78 (7)	O^xiii—Mg—O^xvi	148.51 (10)
O^ii—Ca1—O^iii	94.30 (6)	O^xiv—Mg—O^xvi	127.41 (9)
O^i—Ca1—O^iv	94.31 (6)	O^xv—Mg—O^xvi	77.30 (7)
O^ii—Ca1—O^iv	74.78 (7)	O^xi—Mg—Ir	133.85 (4)
O^iii—Ca1—O^iv	165.64 (9)	O^xii—Mg—Ir	46.15 (5)
O^i—Ca1—O^v	135.01 (4)	O^xiii—Mg—Ir	133.85 (4)
O^ii—Ca1—O^v	72.15 (8)	O^xiv—Mg—Ir	133.85 (4)
O^iii—Ca1—O^v	70.61 (7)	O^xv—Mg—Ir	46.15 (4)
O^iv—Ca1—O^v	113.51 (6)	O^xvi—Mg—Ir	46.15 (4)
O^i—Ca1—O^vi	72.15 (8)	O^xi—Mg—Ir^xvii	46.15 (4)
O^ii—Ca1—O^vi	135.01 (4)	O^xii—Mg—Ir^xvii	133.85 (5)
O^iii—Ca1—O^vi	113.51 (6)	O^xiii—Mg—Ir^xvii	46.15 (4)
O^iv—Ca1—O^vi	70.61 (7)	O^xiv—Mg—Ir^xvii	46.15 (4)
O^v—Ca1—O^vi	148.99 (9)	O^xv—Mg—Ir^xvii	133.85 (4)
O^i—Ca1—O^vii	120.85 (3)	O^xvi—Mg—Ir^xvii	133.85 (4)
O^ii—Ca1—O^vii	138.85 (6)	Ir—Mg—Ir^xvii	180.0
O^iii—Ca1—O^vii	64.89 (9)	O^xi—Mg—Ca1^xviii	105.74 (5)
O^iv—Ca1—O^vii	129.45 (2)	O^xii—Mg—Ca1^xviii	105.74 (5)
O^v—Ca1—O^vii	67.57 (7)	O^xiii—Mg—Ca1^xviii	44.41 (5)
O^vi—Ca1—O^vii	86.00 (6)	O^xiv—Mg—Ca1^xviii	116.30 (5)
O^i—Ca1—O^viii	138.85 (6)	O^xv—Mg—Ca1^xviii	44.41 (5)
O^ii—Ca1—O^viii	120.85 (3)	O^xvi—Mg—Ca1^xviii	116.30 (5)
O^iii—Ca1—O^viii	129.45 (2)	Ir—Mg—Ca1^xviii	90.0
O^iv—Ca1—O^viii	64.89 (9)	Ir^xvii—Mg—Ca1^xviii	90.0
O^v—Ca1—O^viii	86.00 (6)	O^xi—Mg—Ca1^xix	116.30 (5)
O^vi—Ca1—O^viii	67.57 (7)	O^xii—Mg—Ca1^xix	44.41 (5)
O^vii—Ca1—O^viii	64.82 (9)	O^xiii—Mg—Ca1^xix	105.74 (5)
O^i—Ca1—Ir^ix	114.93 (5)	O^xiv—Mg—Ca1^xix	44.41 (5)
O^ii—Ca1—Ir^ix	101.32 (5)	O^xv—Mg—Ca1^xix	116.30 (5)
O^iii—Ca1—Ir^ix	40.24 (4)	O^xvi—Mg—Ca1^xix	105.74 (5)
O^iv—Ca1—Ir^ix	150.04 (5)	Ir—Mg—Ca1^xix	90.0
O^v—Ca1—Ir^ix	40.18 (4)	Ir^xvii—Mg—Ca1^xix	90.0
O^vi—Ca1—Ir^ix	122.94 (4)	Ca1^xviii—Mg—Ca1^xix	120.0
O^vii—Ca1—Ir^ix	39.79 (4)	O^xi—Mg—Ca1^xx	44.41 (5)
O^viii—Ca1—Ir^ix	94.17 (5)	O^xii—Mg—Ca1^xx	116.30 (5)
O^i—Ca1—Ir^iv	101.32 (5)	O^xiii—Mg—Ca1^xx	116.30 (5)
O^ii—Ca1—Ir^iv	114.93 (5)	O^xiv—Mg—Ca1^xx	105.74 (5)
O^iii—Ca1—Ir^iv	150.04 (5)	O^xv—Mg—Ca1^xx	105.74 (5)
O^iv—Ca1—Ir^iv	40.24 (4)	O^xvi—Mg—Ca1^xx	44.41 (5)
O^v—Ca1—Ir^iv	122.94 (4)	Ir—Mg—Ca1^xx	90.0
O^vi—Ca1—Ir^iv	40.18 (4)	Ir^xvii—Mg—Ca1^xx	90.0
O^vii—Ca1—Ir^iv	94.17 (5)	Ca1^xviii—Mg—Ca1^xx	120.0
O^viii—Ca1—Ir^iv	39.79 (4)	Ca1^xix—Mg—Ca1^xx	120.0
Ir^ix—Ca1—Ir^iv	131.33 (2)	O^xi—Mg—Ca1^xxi	104.37 (5)
O^i—Ca1—Ca2^x	41.44 (5)	O^xii—Mg—Ca1^xxi	87.19 (4)
O^ii—Ca1—Ca2^x	41.44 (5)	O^xiii—Mg—Ca1^xxi	45.38 (5)
O^iii—Ca1—Ca2^x	82.82 (5)	O^xiv—Mg—Ca1^xxi	50.32 (5)
O^iv—Ca1—Ca2^x	82.82 (5)	O^xv—Mg—Ca1^xxi	100.27 (5)
O^v—Ca1—Ca2^x	105.50 (5)	O^xvi—Mg—Ca1^xxi	164.47 (5)
O^vi—Ca1—Ca2^x	105.50 (5)	Ir—Mg—Ca1^xxi	121.719 (3)
O^vii—Ca1—Ca2^x	147.59 (4)	Ir^xvii—Mg—Ca1^xxi	58.281 (3)
O^viii—Ca1—Ca2^x	147.59 (4)	Ca1^xviii—Mg—Ca1^xxi	68.478 (11)
Ir^ix—Ca1—Ca2^x	114.333 (12)	Ca1^xix—Mg—Ca1^xxi	61.236 (9)
Ir^iv—Ca1—Ca2^x	114.334 (12)	Ca1^xx—Mg—Ca1^xxi	148.002 (5)
O^i—Ca1—Mg^x	41.44 (5)	O^xv—Ir—O	180.000 (1)
O^ii—Ca1—Mg^x	41.44 (5)	O^xv—Ir—O^xvi	87.62 (8)
O^iii—Ca1—Mg^x	82.82 (5)	O—Ir—O^xvi	92.38 (8)
O^iv—Ca1—Mg^x	82.82 (5)	O^xv—Ir—O^xii	87.62 (8)
O^v—Ca1—Mg^x	105.50 (5)	O—Ir—O^xii	92.38 (8)
O^vi—Ca1—Mg^x	105.50 (5)	O^xvi—Ir—O^xii	87.62 (8)
O^vii—Ca1—Mg^x	147.59 (4)	O^xv—Ir—O^xxii	92.38 (8)
O^viii—Ca1—Mg^x	147.59 (4)	O—Ir—O^xxii	87.62 (8)
Ir^ix—Ca1—Mg^x	114.333 (12)	O^xvi—Ir—O^xxii	180.000 (1)
Ir^iv—Ca1—Mg^x	114.334 (12)	O^xii—Ir—O^xxii	92.38 (8)
Ca2^x—Ca1—Mg^x	0.0	O^xv—Ir—O^xxiii	92.38 (8)
O^xi—Ca2—O^xii	148.51 (10)	O—Ir—O^xxiii	87.62 (8)
O^xi—Ca2—O^xiii	77.30 (7)	O^xvi—Ir—O^xxiii	92.38 (8)
O^xii—Ca2—O^xiii	127.41 (9)	O^xii—Ir—O^xxiii	180.0
O^xi—Ca2—O^xiv	77.30 (7)	O^xxii—Ir—O^xxiii	87.62 (8)
O^xii—Ca2—O^xiv	88.82 (9)	O^xv—Ir—Mg	53.07 (5)
O^xiii—Ca2—O^xiv	77.30 (7)	O—Ir—Mg	126.93 (5)
O^xi—Ca2—O^xv	127.41 (9)	O^xvi—Ir—Mg	53.07 (5)
O^xii—Ca2—O^xv	77.30 (7)	O^xii—Ir—Mg	53.07 (5)
O^xiii—Ca2—O^xv	88.82 (9)	O^xxii—Ir—Mg	126.93 (5)
O^xiv—Ca2—O^xv	148.51 (10)	O^xxiii—Ir—Mg	126.93 (5)
O^xi—Ca2—O^xvi	88.82 (9)	O^xv—Ir—Ca2	53.07 (5)
O^xii—Ca2—O^xvi	77.30 (7)	O—Ir—Ca2	126.93 (5)
O^xiii—Ca2—O^xvi	148.51 (10)	O^xvi—Ir—Ca2	53.07 (5)
O^xiv—Ca2—O^xvi	127.41 (9)	O^xii—Ir—Ca2	53.07 (5)
O^xv—Ca2—O^xvi	77.30 (7)	O^xxii—Ir—Ca2	126.93 (5)
O^xi—Ca2—Ir	133.85 (4)	O^xxiii—Ir—Ca2	126.93 (5)
O^xii—Ca2—Ir	46.15 (5)	Mg—Ir—Ca2	0.0
O^xiii—Ca2—Ir	133.85 (4)	O^xv—Ir—Mg^xv	126.93 (5)
O^xiv—Ca2—Ir	133.85 (4)	O—Ir—Mg^xv	53.07 (5)
O^xv—Ca2—Ir	46.15 (4)	O^xvi—Ir—Mg^xv	126.93 (5)
O^xvi—Ca2—Ir	46.15 (4)	O^xii—Ir—Mg^xv	126.93 (5)
O^xi—Ca2—Ir^xvii	46.15 (4)	O^xxii—Ir—Mg^xv	53.07 (5)
O^xii—Ca2—Ir^xvii	133.85 (5)	O^xxiii—Ir—Mg^xv	53.07 (5)
O^xiii—Ca2—Ir^xvii	46.15 (4)	Mg—Ir—Mg^xv	180.0
O^xiv—Ca2—Ir^xvii	46.15 (4)	Ca2—Ir—Mg^xv	180.0
O^xv—Ca2—Ir^xvii	133.85 (4)	O^xv—Ir—Ca2^xv	126.93 (5)
O^xvi—Ca2—Ir^xvii	133.85 (4)	O—Ir—Ca2^xv	53.07 (5)
Ir—Ca2—Ir^xvii	180.0	O^xvi—Ir—Ca2^xv	126.93 (5)
O^xi—Ca2—Ca1^xviii	105.74 (5)	O^xii—Ir—Ca2^xv	126.93 (5)
O^xii—Ca2—Ca1^xviii	105.74 (5)	O^xxii—Ir—Ca2^xv	53.07 (5)
O^xiii—Ca2—Ca1^xviii	44.41 (5)	O^xxiii—Ir—Ca2^xv	53.07 (5)
O^xiv—Ca2—Ca1^xviii	116.30 (5)	Mg—Ir—Ca2^xv	180.0
O^xv—Ca2—Ca1^xviii	44.41 (5)	Ca2—Ir—Ca2^xv	180.0
O^xvi—Ca2—Ca1^xviii	116.30 (5)	Mg^xv—Ir—Ca2^xv	0.0
Ir—Ca2—Ca1^xviii	90.0	O^xv—Ir—Ca1^xxiv	126.75 (5)
Ir^xvii—Ca2—Ca1^xviii	90.0	O—Ir—Ca1^xxiv	53.25 (5)
O^xi—Ca2—Ca1^xix	116.30 (5)	O^xvi—Ir—Ca1^xxiv	121.25 (6)
O^xii—Ca2—Ca1^xix	44.41 (5)	O^xii—Ir—Ca1^xxiv	54.20 (6)
O^xiii—Ca2—Ca1^xix	105.74 (5)	O^xxii—Ir—Ca1^xxiv	58.75 (6)
O^xiv—Ca2—Ca1^xix	44.41 (5)	O^xxiii—Ir—Ca1^xxiv	125.80 (6)
O^xv—Ca2—Ca1^xix	116.30 (5)	Mg—Ir—Ca1^xxiv	107.173 (2)
O^xvi—Ca2—Ca1^xix	105.74 (5)	Ca2—Ir—Ca1^xxiv	107.173 (2)
Ir—Ca2—Ca1^xix	90.0	Mg^xv—Ir—Ca1^xxiv	72.827 (2)
Ir^xvii—Ca2—Ca1^xix	90.0	Ca2^xv—Ir—Ca1^xxiv	72.827 (2)
Ca1^xviii—Ca2—Ca1^xix	120.0	O^xv—Ir—Ca1^xxv	53.25 (5)
O^xi—Ca2—Ca1^xx	44.41 (5)	O—Ir—Ca1^xxv	126.75 (5)
O^xii—Ca2—Ca1^xx	116.30 (5)	O^xvi—Ir—Ca1^xxv	58.75 (6)
O^xiii—Ca2—Ca1^xx	116.30 (5)	O^xii—Ir—Ca1^xxv	125.80 (6)
O^xiv—Ca2—Ca1^xx	105.74 (5)	O^xxii—Ir—Ca1^xxv	121.25 (6)
O^xv—Ca2—Ca1^xx	105.74 (5)	O^xxiii—Ir—Ca1^xxv	54.20 (6)
O^xvi—Ca2—Ca1^xx	44.41 (5)	Mg—Ir—Ca1^xxv	72.827 (2)
Ir—Ca2—Ca1^xx	90.0	Ca2—Ir—Ca1^xxv	72.827 (2)
Ir^xvii—Ca2—Ca1^xx	90.0	Mg^xv—Ir—Ca1^xxv	107.173 (2)
Ca1^xviii—Ca2—Ca1^xx	120.0	Ca2^xv—Ir—Ca1^xxv	107.173 (2)
Ca1^xix—Ca2—Ca1^xx	120.0	Ca1^xxiv—Ir—Ca1^xxv	180.0
O^xi—Ca2—Ca1^xxi	104.37 (5)	Ir—O—Mg^xv	80.78 (7)
O^xii—Ca2—Ca1^xxi	87.19 (4)	Ir—O—Ca2^xv	80.78 (7)
O^xiii—Ca2—Ca1^xxi	45.38 (5)	Mg^xv—O—Ca2^xv	0.0
O^xiv—Ca2—Ca1^xxi	50.32 (5)	Ir—O—Ca1^ii	167.66 (10)
O^xv—Ca2—Ca1^xxi	100.27 (5)	Mg^xv—O—Ca1^ii	94.15 (6)
O^xvi—Ca2—Ca1^xxi	164.47 (5)	Ca2^xv—O—Ca1^ii	94.15 (6)
Ir—Ca2—Ca1^xxi	121.719 (3)	Ir—O—Ca1^xxiv	86.52 (7)
Ir^xvii—Ca2—Ca1^xxi	58.281 (3)	Mg^xv—O—Ca1^xxiv	95.12 (7)
Ca1^xviii—Ca2—Ca1^xxi	68.478 (11)	Ca2^xv—O—Ca1^xxiv	95.12 (7)
Ca1^xix—Ca2—Ca1^xxi	61.236 (9)	Ca1^ii—O—Ca1^xxiv	105.22 (7)
Ca1^xx—Ca2—Ca1^xxi	148.002 (5)	Ir—O—Ca1^xxvi	85.61 (6)
O^xi—Mg—O^xii	148.51 (10)	Mg^xv—O—Ca1^xxvi	165.80 (8)
O^xi—Mg—O^xiii	77.30 (7)	Ca2^xv—O—Ca1^xxvi	165.80 (8)
O^xii—Mg—O^xiii	127.41 (9)	Ca1^ii—O—Ca1^xxvi	98.38 (7)
O^xi—Mg—O^xiv	77.30 (7)	Ca1^xxiv—O—Ca1^xxvi	88.04 (6)
O^xii—Mg—O^xiv	88.82 (9)	Ir—O—Ca1^xxvii	81.46 (6)
O^xiii—Mg—O^xiv	77.30 (7)	Mg^xv—O—Ca1^xxvii	89.99 (6)
O^xi—Mg—O^xv	127.41 (9)	Ca2^xv—O—Ca1^xxvii	89.99 (6)
O^xii—Mg—O^xv	77.30 (7)	Ca1^ii—O—Ca1^xxvii	87.33 (6)
O^xiii—Mg—O^xv	88.82 (9)	Ca1^xxiv—O—Ca1^xxvii	166.03 (7)
O^xiv—Mg—O^xv	148.51 (10)	Ca1^xxvi—O—Ca1^xxvii	83.98 (6)
O^xi—Mg—O^xvi	88.82 (9)

Symmetry codes: (i) −x+y+2/3, y+1/3, z−7/6; (ii) −x+2/3, −y+1/3, −z+4/3; (iii) x−y+1/3, −y+2/3, −z+7/6; (iv) x, y, z−1; (v) −y+1/3, −x+2/3, z−5/6; (vi) x−y, x, −z+1; (vii) −x+1/3, −x+y+2/3, −z+7/6; (viii) −y, x−y, z−1; (ix) y+1/3, x+2/3, −z+7/6; (x) x+2/3, y+1/3, z−2/3; (xi) −y, −x, z−1/2; (xii) x−y, x, −z+2; (xiii) −x+y, y, z−1/2; (xiv) x, x−y, z−1/2; (xv) −x, −y, −z+2; (xvi) y, −x+y, −z+2; (xvii) y, x, −z+3/2; (xviii) x−2/3, y−1/3, z+2/3; (xix) −x+y+1/3, −x+2/3, z+2/3; (xx) −y+1/3, x−y−1/3, z+2/3; (xxi) −x+1/3, −y+2/3, −z+2/3; (xxii) −y, x−y, z; (xxiii) −x+y, −x, z; (xxiv) x, y, z+1; (xxv) −x, −y, −z+1; (xxvi) y, −x+y, −z+1; (xxvii) −x+y, −x, z+1.

(III) Tricalcium zinc iridium hexaoxide

Crystal data

Ca3.50Zn0.50IrO6	Dx = 5.605 Mg m^−3
Mr = 461.17	Mo Kα radiation, λ = 0.71073 Å
Trigonal, R3c	Cell parameters from 1927 reflections
a = 9.2641 (3) Å	θ = 4.4–36.3°
c = 11.0298 (5) Å	µ = 29.82 mm^−1
V = 819.79 (5) Å^3	T = 293 K
Z = 6	Block, black
F(000) = 1260	0.10 × 0.06 × 0.05 mm

Data collection

Bruker SMART APEX CCD are-detector diffractometer	448 independent reflections
Radiation source: fine-focus sealed tube	398 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.034
ω scans	θmax = 36.3°, θmin = 4.4°
Absorption correction: multi-scan (SADABS; Bruker, 1997)	h = −14→7
Tmin = 0.171, Tmax = 0.344	k = −10→15
2889 measured reflections	l = −10→18

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)] = 0.031	Secondary atom site location: difference Fourier map
wR(F^2) = 0.077	w = 1/[σ^2(Fo^2) + (0.0496P)^2] where P = (Fo^2 + 2Fc^2)/3
S = 1.13	(Δ/σ)max < 0.001
448 reflections	Δρmax = 4.57 e Å^−3
19 parameters	Δρmin = −3.54 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	Occ. (<1)
O	0.1585 (4)	0.9738 (4)	0.3897 (3)	0.0115 (6)
Ir	0.0000	1.0000	0.5000	0.00439 (13)
Ca1	0.97173 (12)	0.6667	0.4167	0.0073 (2)
Zn	0.0000	1.0000	0.2500	0.0087 (3)	0.50
Ca2	0.0000	1.0000	0.2500	0.0087 (3)	0.50

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O	0.0103 (13)	0.0126 (13)	0.0137 (13)	0.0073 (12)	0.0054 (11)	−0.0016 (10)
Ir	0.00377 (14)	0.00377 (14)	0.00563 (19)	0.00188 (7)	0.000	0.000
Ca1	0.0066 (3)	0.0065 (4)	0.0088 (4)	0.0033 (2)	−0.00040 (18)	−0.0008 (4)
Zn	0.0099 (5)	0.0099 (5)	0.0064 (6)	0.0050 (2)	0.000	0.000
Ca2	0.0099 (5)	0.0099 (5)	0.0064 (6)	0.0050 (2)	0.000	0.000

Geometric parameters (Å, º)

O—Ir	2.012 (3)	Ca1—O^xvii	2.675 (3)
O—Ca2	2.223 (3)	Ca1—Ir^xvii	3.1049 (5)
O—Zn	2.223 (3)	Ca1—Ir^xiii	3.1049 (5)
O—Ca1^i	2.349 (3)	Ca1—Ca2^i	3.3499 (11)
O—Ca1^ii	2.501 (3)	Ca1—Zn^i	3.3499 (11)
O—Ca1^iii	2.536 (3)	Zn—O^xviii	2.223 (3)
O—Ca1^iv	2.675 (3)	Zn—O^ix	2.223 (3)
Ir—O^v	2.012 (3)	Zn—O^v	2.223 (3)
Ir—O^vi	2.012 (3)	Zn—O^xix	2.223 (3)
Ir—O^vii	2.012 (3)	Zn—O^xx	2.223 (3)
Ir—O^viii	2.012 (3)	Zn—Ir^xx	2.7575 (1)
Ir—O^ix	2.012 (3)	Zn—Ca1^xxi	3.3499 (11)
Ir—Ca2^viii	2.7575 (1)	Zn—Ca1^xxii	3.3499 (11)
Ir—Ca2	2.7575 (1)	Zn—Ca1^i	3.3499 (11)
Ir—Zn	2.7575 (1)	Zn—Ca1^xxiii	3.4893 (4)
Ir—Zn^viii	2.7575 (1)	Ca2—O^xviii	2.223 (3)
Ir—Ca1^x	3.1049 (5)	Ca2—O^ix	2.223 (3)
Ir—Ca1^iv	3.1049 (5)	Ca2—O^v	2.223 (3)
Ca1—O^xi	2.349 (3)	Ca2—O^xix	2.223 (3)
Ca1—O^i	2.349 (3)	Ca2—O^xx	2.223 (3)
Ca1—O^xii	2.501 (3)	Ca2—Ir^xx	2.7575 (1)
Ca1—O^xiii	2.501 (3)	Ca2—Ca1^xxi	3.3499 (11)
Ca1—O^xiv	2.536 (3)	Ca2—Ca1^xxii	3.3499 (11)
Ca1—O^xv	2.536 (3)	Ca2—Ca1^i	3.3499 (11)
Ca1—O^xvi	2.675 (3)	Ca2—Ca1^xxiii	3.4893 (4)
Ir—O—Ca2	81.07 (11)	O^i—Ca1—Zn^i	41.45 (8)
Ir—O—Zn	81.07 (11)	O^xii—Ca1—Zn^i	82.95 (8)
Ca2—O—Zn	0.0	O^xiii—Ca1—Zn^i	82.95 (8)
Ir—O—Ca1^i	168.27 (17)	O^xiv—Ca1—Zn^i	105.30 (8)
Ca2—O—Ca1^i	94.17 (12)	O^xv—Ca1—Zn^i	105.30 (8)
Zn—O—Ca1^i	94.17 (12)	O^xvi—Ca1—Zn^i	147.58 (7)
Ir—O—Ca1^ii	86.22 (11)	O^xvii—Ca1—Zn^i	147.58 (7)
Ca2—O—Ca1^ii	95.03 (12)	Ir^xvii—Ca1—Zn^i	114.390 (19)
Zn—O—Ca1^ii	95.03 (12)	Ir^xiii—Ca1—Zn^i	114.390 (19)
Ca1^i—O—Ca1^ii	104.95 (11)	Ca2^i—Ca1—Zn^i	0.0
Ir—O—Ca1^iii	85.27 (11)	O^xviii—Zn—O^ix	148.01 (17)
Ca2—O—Ca1^iii	165.85 (14)	O^xviii—Zn—O	127.90 (16)
Zn—O—Ca1^iii	165.85 (14)	O^ix—Zn—O	77.27 (12)
Ca1^i—O—Ca1^iii	98.55 (12)	O^xviii—Zn—O^v	88.76 (16)
Ca1^ii—O—Ca1^iii	87.68 (10)	O^ix—Zn—O^v	77.27 (12)
Ir—O—Ca1^iv	81.63 (10)	O—Zn—O^v	77.27 (12)
Ca2—O—Ca1^iv	90.35 (11)	O^xviii—Zn—O^xix	77.27 (12)
Zn—O—Ca1^iv	90.35 (11)	O^ix—Zn—O^xix	127.90 (16)
Ca1^i—O—Ca1^iv	87.71 (10)	O—Zn—O^xix	88.76 (16)
Ca1^ii—O—Ca1^iv	165.79 (13)	O^v—Zn—O^xix	148.01 (17)
Ca1^iii—O—Ca1^iv	84.01 (10)	O^xviii—Zn—O^xx	77.27 (12)
O^v—Ir—O^vi	180.000 (1)	O^ix—Zn—O^xx	88.76 (16)
O^v—Ir—O	87.24 (14)	O—Zn—O^xx	148.01 (17)
O^vi—Ir—O	92.76 (14)	O^v—Zn—O^xx	127.90 (16)
O^v—Ir—O^vii	92.76 (14)	O^xix—Zn—O^xx	77.27 (12)
O^vi—Ir—O^vii	87.24 (14)	O^xviii—Zn—Ir^xx	46.13 (8)
O—Ir—O^vii	92.76 (14)	O^ix—Zn—Ir^xx	133.87 (8)
O^v—Ir—O^viii	92.76 (14)	O—Zn—Ir^xx	133.87 (8)
O^vi—Ir—O^viii	87.24 (14)	O^v—Zn—Ir^xx	133.87 (8)
O—Ir—O^viii	180.000 (1)	O^xix—Zn—Ir^xx	46.13 (8)
O^vii—Ir—O^viii	87.24 (14)	O^xx—Zn—Ir^xx	46.13 (8)
O^v—Ir—O^ix	87.24 (14)	O^xviii—Zn—Ir	133.87 (8)
O^vi—Ir—O^ix	92.76 (14)	O^ix—Zn—Ir	46.13 (8)
O—Ir—O^ix	87.24 (14)	O—Zn—Ir	46.13 (8)
O^vii—Ir—O^ix	180.000 (1)	O^v—Zn—Ir	46.13 (8)
O^viii—Ir—O^ix	92.76 (14)	O^xix—Zn—Ir	133.87 (8)
O^v—Ir—Ca2^viii	127.20 (9)	O^xx—Zn—Ir	133.87 (8)
O^vi—Ir—Ca2^viii	52.80 (10)	Ir^xx—Zn—Ir	180.0
O—Ir—Ca2^viii	127.20 (9)	O^xviii—Zn—Ca1^xxi	116.05 (8)
O^vii—Ir—Ca2^viii	52.80 (9)	O^ix—Zn—Ca1^xxi	44.38 (8)
O^viii—Ir—Ca2^viii	52.80 (9)	O—Zn—Ca1^xxi	116.05 (8)
O^ix—Ir—Ca2^viii	127.20 (9)	O^v—Zn—Ca1^xxi	106.00 (8)
O^v—Ir—Ca2	52.80 (9)	O^xix—Zn—Ca1^xxi	106.00 (8)
O^vi—Ir—Ca2	127.20 (10)	O^xx—Zn—Ca1^xxi	44.38 (8)
O—Ir—Ca2	52.80 (9)	Ir^xx—Zn—Ca1^xxi	90.0
O^vii—Ir—Ca2	127.20 (9)	Ir—Zn—Ca1^xxi	90.0
O^viii—Ir—Ca2	127.20 (9)	O^xviii—Zn—Ca1^xxii	44.38 (8)
O^ix—Ir—Ca2	52.80 (9)	O^ix—Zn—Ca1^xxii	116.05 (8)
Ca2^viii—Ir—Ca2	180.0	O—Zn—Ca1^xxii	106.00 (8)
O^v—Ir—Zn	52.80 (9)	O^v—Zn—Ca1^xxii	44.38 (8)
O^vi—Ir—Zn	127.20 (10)	O^xix—Zn—Ca1^xxii	116.05 (8)
O—Ir—Zn	52.80 (9)	O^xx—Zn—Ca1^xxii	106.00 (8)
O^vii—Ir—Zn	127.20 (9)	Ir^xx—Zn—Ca1^xxii	90.0
O^viii—Ir—Zn	127.20 (9)	Ir—Zn—Ca1^xxii	90.0
O^ix—Ir—Zn	52.80 (9)	Ca1^xxi—Zn—Ca1^xxii	120.0
Ca2^viii—Ir—Zn	180.0	O^xviii—Zn—Ca1^i	106.00 (8)
Ca2—Ir—Zn	0.0	O^ix—Zn—Ca1^i	106.00 (8)
O^v—Ir—Zn^viii	127.20 (9)	O—Zn—Ca1^i	44.38 (8)
O^vi—Ir—Zn^viii	52.80 (10)	O^v—Zn—Ca1^i	116.05 (8)
O—Ir—Zn^viii	127.20 (9)	O^xix—Zn—Ca1^i	44.38 (8)
O^vii—Ir—Zn^viii	52.80 (9)	O^xx—Zn—Ca1^i	116.05 (8)
O^viii—Ir—Zn^viii	52.80 (9)	Ir^xx—Zn—Ca1^i	90.0
O^ix—Ir—Zn^viii	127.20 (9)	Ir—Zn—Ca1^i	90.0
Ca2^viii—Ir—Zn^viii	0.0	Ca1^xxi—Zn—Ca1^i	120.0
Ca2—Ir—Zn^viii	180.0	Ca1^xxii—Zn—Ca1^i	120.0
Zn—Ir—Zn^viii	180.0	O^xviii—Zn—Ca1^xxiii	50.06 (8)
O^v—Ir—Ca1^x	54.50 (10)	O^ix—Zn—Ca1^xxiii	100.07 (8)
O^vi—Ir—Ca1^x	125.50 (10)	O—Zn—Ca1^xxiii	164.73 (8)
O—Ir—Ca1^x	121.52 (9)	O^v—Zn—Ca1^xxiii	87.47 (8)
O^vii—Ir—Ca1^x	53.49 (9)	O^xix—Zn—Ca1^xxiii	104.28 (8)
O^viii—Ir—Ca1^x	58.48 (9)	O^xx—Zn—Ca1^xxiii	45.57 (8)
O^ix—Ir—Ca1^x	126.51 (9)	Ir^xx—Zn—Ca1^xxiii	58.207 (4)
Ca2^viii—Ir—Ca1^x	72.781 (3)	Ir—Zn—Ca1^xxiii	121.793 (5)
Ca2—Ir—Ca1^x	107.219 (3)	Ca1^xxi—Zn—Ca1^xxiii	68.442 (17)
Zn—Ir—Ca1^x	107.219 (3)	Ca1^xxii—Zn—Ca1^xxiii	61.313 (14)
Zn^viii—Ir—Ca1^x	72.781 (3)	Ca1^i—Zn—Ca1^xxiii	147.937 (7)
O^v—Ir—Ca1^iv	125.50 (10)	O^xviii—Ca2—O^ix	148.01 (17)
O^vi—Ir—Ca1^iv	54.50 (10)	O^xviii—Ca2—O	127.90 (16)
O—Ir—Ca1^iv	58.48 (9)	O^ix—Ca2—O	77.27 (12)
O^vii—Ir—Ca1^iv	126.51 (9)	O^xviii—Ca2—O^v	88.76 (16)
O^viii—Ir—Ca1^iv	121.52 (9)	O^ix—Ca2—O^v	77.27 (12)
O^ix—Ir—Ca1^iv	53.49 (9)	O—Ca2—O^v	77.27 (12)
Ca2^viii—Ir—Ca1^iv	107.219 (3)	O^xviii—Ca2—O^xix	77.27 (12)
Ca2—Ir—Ca1^iv	72.781 (3)	O^ix—Ca2—O^xix	127.90 (16)
Zn—Ir—Ca1^iv	72.781 (3)	O—Ca2—O^xix	88.76 (16)
Zn^viii—Ir—Ca1^iv	107.219 (3)	O^v—Ca2—O^xix	148.01 (17)
Ca1^x—Ir—Ca1^iv	180.0	O^xviii—Ca2—O^xx	77.27 (12)
O^xi—Ca1—O^i	82.90 (17)	O^ix—Ca2—O^xx	88.76 (16)
O^xi—Ca1—O^xii	75.05 (11)	O—Ca2—O^xx	148.01 (17)
O^i—Ca1—O^xii	94.25 (10)	O^v—Ca2—O^xx	127.90 (16)
O^xi—Ca1—O^xiii	94.25 (10)	O^xix—Ca2—O^xx	77.27 (12)
O^i—Ca1—O^xiii	75.05 (11)	O^xviii—Ca2—Ir^xx	46.13 (8)
O^xii—Ca1—O^xiii	165.90 (15)	O^ix—Ca2—Ir^xx	133.87 (8)
O^xi—Ca1—O^xiv	135.08 (6)	O—Ca2—Ir^xx	133.87 (8)
O^i—Ca1—O^xiv	71.79 (13)	O^v—Ca2—Ir^xx	133.87 (8)
O^xii—Ca1—O^xiv	70.67 (12)	O^xix—Ca2—Ir^xx	46.13 (8)
O^xiii—Ca1—O^xiv	113.31 (11)	O^xx—Ca2—Ir^xx	46.13 (8)
O^xi—Ca1—O^xv	71.79 (13)	O^xviii—Ca2—Ir	133.87 (8)
O^i—Ca1—O^xv	135.08 (6)	O^ix—Ca2—Ir	46.13 (8)
O^xii—Ca1—O^xv	113.31 (11)	O—Ca2—Ir	46.13 (8)
O^xiii—Ca1—O^xv	70.67 (12)	O^v—Ca2—Ir	46.13 (8)
O^xiv—Ca1—O^xv	149.39 (15)	O^xix—Ca2—Ir	133.87 (8)
O^xi—Ca1—O^xvi	138.81 (11)	O^xx—Ca2—Ir	133.87 (8)
O^i—Ca1—O^xvi	120.86 (5)	Ir^xx—Ca2—Ir	180.0
O^xii—Ca1—O^xvi	129.31 (4)	O^xviii—Ca2—Ca1^xxi	116.05 (8)
O^xiii—Ca1—O^xvi	64.77 (14)	O^ix—Ca2—Ca1^xxi	44.38 (8)
O^xiv—Ca1—O^xvi	86.00 (10)	O—Ca2—Ca1^xxi	116.05 (8)
O^xv—Ca1—O^xvi	67.92 (12)	O^v—Ca2—Ca1^xxi	106.00 (8)
O^xi—Ca1—O^xvii	120.86 (5)	O^xix—Ca2—Ca1^xxi	106.00 (8)
O^i—Ca1—O^xvii	138.81 (11)	O^xx—Ca2—Ca1^xxi	44.38 (8)
O^xii—Ca1—O^xvii	64.77 (14)	Ir^xx—Ca2—Ca1^xxi	90.0
O^xiii—Ca1—O^xvii	129.31 (4)	Ir—Ca2—Ca1^xxi	90.0
O^xiv—Ca1—O^xvii	67.92 (13)	O^xviii—Ca2—Ca1^xxii	44.38 (8)
O^xv—Ca1—O^xvii	86.00 (10)	O^ix—Ca2—Ca1^xxii	116.05 (8)
O^xvi—Ca1—O^xvii	64.83 (14)	O—Ca2—Ca1^xxii	106.00 (8)
O^xi—Ca1—Ir^xvii	115.26 (8)	O^v—Ca2—Ca1^xxii	44.38 (8)
O^i—Ca1—Ir^xvii	101.09 (8)	O^xix—Ca2—Ca1^xxii	116.05 (8)
O^xii—Ca1—Ir^xvii	40.29 (7)	O^xx—Ca2—Ca1^xxii	106.00 (8)
O^xiii—Ca1—Ir^xvii	149.78 (8)	Ir^xx—Ca2—Ca1^xxii	90.0
O^xiv—Ca1—Ir^xvii	40.23 (7)	Ir—Ca2—Ca1^xxii	90.0
O^xv—Ca1—Ir^xvii	123.06 (8)	Ca1^xxi—Ca2—Ca1^xxii	120.0
O^xvi—Ca1—Ir^xvii	94.02 (8)	O^xviii—Ca2—Ca1^i	106.00 (8)
O^xvii—Ca1—Ir^xvii	39.88 (7)	O^ix—Ca2—Ca1^i	106.00 (8)
O^xi—Ca1—Ir^xiii	101.09 (8)	O—Ca2—Ca1^i	44.38 (8)
O^i—Ca1—Ir^xiii	115.26 (8)	O^v—Ca2—Ca1^i	116.05 (8)
O^xii—Ca1—Ir^xiii	149.78 (8)	O^xix—Ca2—Ca1^i	44.38 (8)
O^xiii—Ca1—Ir^xiii	40.29 (7)	O^xx—Ca2—Ca1^i	116.05 (8)
O^xiv—Ca1—Ir^xiii	123.06 (8)	Ir^xx—Ca2—Ca1^i	90.0
O^xv—Ca1—Ir^xiii	40.23 (7)	Ir—Ca2—Ca1^i	90.0
O^xvi—Ca1—Ir^xiii	39.88 (7)	Ca1^xxi—Ca2—Ca1^i	120.0
O^xvii—Ca1—Ir^xiii	94.02 (7)	Ca1^xxii—Ca2—Ca1^i	120.0
Ir^xvii—Ca1—Ir^xiii	131.22 (4)	O^xviii—Ca2—Ca1^xxiii	50.06 (8)
O^xi—Ca1—Ca2^i	41.45 (8)	O^ix—Ca2—Ca1^xxiii	100.07 (8)
O^i—Ca1—Ca2^i	41.45 (8)	O—Ca2—Ca1^xxiii	164.73 (8)
O^xii—Ca1—Ca2^i	82.95 (8)	O^v—Ca2—Ca1^xxiii	87.47 (8)
O^xiii—Ca1—Ca2^i	82.95 (8)	O^xix—Ca2—Ca1^xxiii	104.28 (8)
O^xiv—Ca1—Ca2^i	105.30 (8)	O^xx—Ca2—Ca1^xxiii	45.57 (8)
O^xv—Ca1—Ca2^i	105.30 (8)	Ir^xx—Ca2—Ca1^xxiii	58.207 (4)
O^xvi—Ca1—Ca2^i	147.58 (7)	Ir—Ca2—Ca1^xxiii	121.793 (5)
O^xvii—Ca1—Ca2^i	147.58 (7)	Ca1^xxi—Ca2—Ca1^xxiii	68.442 (17)
Ir^xvii—Ca1—Ca2^i	114.390 (19)	Ca1^xxii—Ca2—Ca1^xxiii	61.313 (14)
Ir^xiii—Ca1—Ca2^i	114.390 (19)	Ca1^i—Ca2—Ca1^xxiii	147.937 (7)
O^xi—Ca1—Zn^i	41.45 (8)

Symmetry codes: (i) −x+4/3, −y+5/3, −z+2/3; (ii) x−1, y, z; (iii) x−y, x, −z+1; (iv) −y+1, x−y+1, z; (v) −x+y−1, −x+1, z; (vi) x−y+1, x+1, −z+1; (vii) y−1, −x+y, −z+1; (viii) −x, −y+2, −z+1; (ix) −y+1, x−y+2, z; (x) y−1, −x+y+1, −z+1; (xi) −x+y+1/3, y−1/3, z+1/6; (xii) x−y+5/3, −y+4/3, −z+5/6; (xiii) x+1, y, z; (xiv) x+2/3, x−y+4/3, z−1/6; (xv) y, −x+y, −z+1; (xvi) −x+y, −x+1, z; (xvii) y−1/3, x+1/3, −z+5/6; (xviii) −x, −x+y, −z+1/2; (xix) x−y+1, −y+2, −z+1/2; (xx) y−1, x+1, −z+1/2; (xxi) y−2/3, −x+y+5/3, −z+2/3; (xxii) x−y−2/3, x−1/3, −z+2/3; (xxiii) −y+1/3, x−y+2/3, z−1/3.