A three-dimensional iodo-bridged mixed-valence gold(I,III) compound, Rb₂[Au^II₂][Au^IIII₄]

Rb₂[Au^II₂][Au^IIII₄], dirubidium diiodo­aurate(I) tetra­iodo­aurate(III), has a tilted and distorted perovskite-type structure which is isotypic with its bromide analogue Rb₂[Au^IBr₂][Au^IIIBr₄]. The structure contains compressed and elongated [AuI₆] octa­hedra tilted away from each other and stacked alternately along the [001], [10] and [110] directions by sharing all the corner I^- ions.

Key indicators

• Single-crystal X-ray study
• T = 295 K
• Mean [sigma](u-I) = 0.002 Å
• R factor = 0.066
• wR factor = 0.097
• Data-to-parameter ratio = 35.4

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT042_ALERT_1_C Calc. and Rep. MoietyFormula Strings Differ ....          ?
PLAT128_ALERT_4_C Non-standard setting of Space group C2/m    ....    I2/m

Alert level G
ABSTM02_ALERT_3_G  The ratio of expected to reported Tmax/Tmin(RR) is > 1.50
            Tmin and Tmax reported:      0.051     0.157
            Tmin and Tmax expected:      0.024     0.123
            RR =      1.657
            Please check that your absorption correction is appropriate.

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   2 ALERT level C = Check and explain
   1 ALERT level G = General alerts; check

   1 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   0 ALERT type 2 Indicator that the structure model may be wrong or deficient
   1 ALERT type 3 Indicator that the structure quality may be low
   1 ALERT type 4 Improvement, methodology, query or suggestion

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Computing details

Data collection: Rigaku/AFC Diffractometer Control Software (Rigaku, 1987); cell refinement: Rigaku/AFC Diffractometer Control Software; data reduction: Rigaku/AFC Diffractometer Control Software; program(s) used to solve structure: UNICS3 (Sakurai & Kobayashi, 1979); program(s) used to refine structure: SHELX76 (Sheldrick, 1976); molecular graphics: DIAMOND (Brandenburg, 2005); software used to prepare material for publication: PLATON (Spek, 2003).

Dirubidium diiodoaurate(I) tetraiodoaurate(III)

Crystal data

Rb2[AuI2][AuI4]	F(000) = 1100
Mr = 1326.28	Dx = 5.39 Mg m^−3
Monoclinic, I2/m	Mo Kα radiation, λ = 0.71069 Å
Hall symbol: -I 2y	Cell parameters from 25 reflections
a = 8.725 (2) Å	θ = 10.0–14.8°
b = 7.932 (1) Å	µ = 34.88 mm^−1
c = 11.969 (4) Å	T = 295 K
β = 99.53 (2)°	Plate, gold
V = 816.9 (3) Å^3	0.20 × 0.10 × 0.06 mm
Z = 2

Data collection

Rigaku AFC-5S diffractometer	1098 reflections with F > 3σ(F)
Radiation source: X-ray sealed tube	Rint = 0.010
Graphite monochromator	θmax = 32.5°, θmin = 2.7°
θ/2θ scans	h = −3→13
Absorption correction: gaussian (Coppens et al., 1965)	k = −11→0
Tmin = 0.051, Tmax = 0.157	l = −18→17
1793 measured reflections	4 standard reflections every 50 reflections
1390 independent reflections	intensity decay: none

Refinement

Refinement on F	Primary atom site location: heavy-atom method
Least-squares matrix: full	w = 1/[σ^2(Fo) + 0.0012Fo^2]
R[F^2 > 2σ(F^2)] = 0.066	(Δ/σ)max < 0.001
wR(F^2) = 0.097	Δρmax = 3.08 e Å^−3
S = 1.72	Δρmin = −3.89 e Å^−3
1098 reflections	Extinction correction: SHELX76 (Sheldrick, 1976), Fc^*=kFc[1-0.0001xFc^2/sin(θ)]
31 parameters	Extinction coefficient: 0.00046 (8)
0 restraints

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

	x	y	z	Uiso*/Ueq
Au1	0.0000	0.0000	0.0000	0.0279 (5)
Au2	0.5000	0.5000	0.0000	0.0367 (5)
Rb	−0.0029 (5)	0.5000	0.2328 (4)	0.0699 (17)
I1	0.2180 (2)	0.2344 (2)	0.03572 (16)	0.0504 (5)
I2	0.5679 (3)	0.5000	0.21716 (18)	0.0482 (7)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Au1	0.0302 (8)	0.0238 (7)	0.0294 (9)	0.000	0.0039 (6)	0.000
Au2	0.0391 (9)	0.0463 (9)	0.0252 (8)	0.000	0.0064 (6)	0.000
Rb	0.065 (3)	0.069 (3)	0.070 (3)	0.000	−0.006 (2)	0.000
I1	0.0490 (9)	0.0378 (8)	0.0611 (11)	−0.0151 (7)	−0.0007 (8)	0.0014 (7)
I2	0.0545 (13)	0.0653 (15)	0.0249 (10)	0.000	0.0065 (9)	0.000

Geometric parameters (Å, º)

Au1—I1	2.6435 (19)	Au2—I1	3.320 (2)
Au1—I2^i	3.532 (2)	Au1—Au2	5.896 (2)
Au2—I2	2.568 (2)	Au1^ii—Au2	5.984 (2)
I1—Au1—I1^iii	89.39 (6)	I2—Au2—I1^vii	94.51 (6)
I1—Au1—I1^iv	90.61 (6)	I1—Au2—I1^viii	78.77 (5)
I1—Au1—I2^v	85.68 (5)	I1—Au2—I1^vii	101.23 (5)
I1—Au1—I2^vi	94.32 (5)	Au1—I1—Au2	162.59 (7)
I2—Au2—I1	85.49 (6)	Au2—I2—Au1^ii	157.33 (10)

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