Rb₂Cd₃(SO₄)₃(OH)₂·2H₂O: structural stability at 500 K

The title compound, dirubidium tricadmium tris­(sulfate) dihydroxide dihydrate, consists of sheets of CdO₆ octa­hedra and sulfate tetra­hedra propagating in the (100) plane, with Rb⁺ ions in the inter­layer positions. It is isostructural with K₂Co₃(SO₄)₃(OH)₂·2H₂O

Key indicators

• Single-crystal X-ray study
• T = 500 K
• Mean [sigma](S-O) = 0.011 Å
• R factor = 0.058
• wR factor = 0.138
• Data-to-parameter ratio = 12.2

checkCIF/PLATON results

No syntax errors found



Alert level B
PLAT241_ALERT_2_B Check High      Ueq as Compared to Neighbors for         O5
PLAT242_ALERT_2_B Check Low       Ueq as Compared to Neighbors for         S2

Alert level C
PLAT061_ALERT_3_C Tmax/Tmin Range Test RR' too Large .............       0.89
PLAT241_ALERT_2_C Check High      Ueq as Compared to Neighbors for         O1
PLAT242_ALERT_2_C Check Low       Ueq as Compared to Neighbors for        Cd2
PLAT242_ALERT_2_C Check Low       Ueq as Compared to Neighbors for         S1

Alert level G
REFLT03_ALERT_4_G Please check that the estimate of the number of Friedel pairs is
            correct. If it is not, please give the correct count in the
            _publ_section_exptl_refinement section of the submitted CIF.
           From the CIF: _diffrn_reflns_theta_max           27.29
           From the CIF: _reflns_number_total               1616
           Count of symmetry unique reflns          951
           Completeness (_total/calc)            169.93%
           TEST3: Check Friedels for noncentro structure
           Estimate of Friedel pairs measured       665
           Fraction of Friedel pairs measured     0.699
           Are heavy atom types Z>Si present        yes

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

   0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   5 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: SMART (Bruker, 1998); cell refinement: SMART; data reduction: SAINT (Bruker, 1998); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997) and CAMERON (Betteridge et al., 2003; software used to prepare material for publication: WinGX (Farrugia, 1999) and PLATON (Spek, 2003).

dirubidium tricadmium tris(sulfate) dihydroxide dihydrate

Crystal data

Rb2Cd3(SO4)3(OH)2·2H2O	F(000) = 1600
Mr = 866.43	Dx = 3.738 Mg m^−3
Orthorhombic, Cmc21	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: C 2c -2	Cell parameters from 746 reflections
a = 19.116 (4) Å	θ = 0.9–27.3°
b = 8.0147 (13) Å	µ = 10.88 mm^−1
c = 10.0475 (17) Å	T = 500 K
V = 1539.4 (5) Å^3	Block, colourless
Z = 4	0.30 × 0.25 × 0.20 mm

Data collection

Bruker SMART CCD area-detector diffractometer	1616 independent reflections
Radiation source: fine-focus sealed tube	1585 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.033
φ and ω scans	θmax = 27.3°, θmin = 2.1°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −23→23
Tmin = 0.043, Tmax = 0.114	k = −9→9
7592 measured reflections	l = −12→12

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.058	H-atom parameters constrained
wR(F^2) = 0.138	w = 1/[σ^2(Fo^2) + (0.1068P)^2] where P = (Fo^2 + 2Fc^2)/3
S = 1.18	(Δ/σ)max < 0.001
1616 reflections	Δρmax = 1.95 e Å^−3
133 parameters	Δρmin = −1.17 e Å^−3
1 restraint	Absolute structure: Flack (1983), 665 Friedel pairs
Primary atom site location: structure-invariant direct methods	Absolute structure parameter: 0.04 (2)

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
Cd1	0.41228 (3)	0.03574 (8)	0.83389 (10)	0.0510 (3)
Cd2	0.0000	−0.19241 (11)	0.55018 (9)	0.0475 (3)
Rb	0.19167 (7)	0.03705 (14)	0.78629 (15)	0.0732 (4)
S1	0.32533 (11)	−0.1978 (3)	1.0587 (3)	0.0475 (5)
S2	0.0000	−0.1875 (4)	0.2154 (3)	0.0466 (7)
O1	0.3225 (5)	−0.1159 (13)	0.9275 (9)	0.065 (2)
O2	0.3796 (4)	−0.3298 (10)	1.0583 (12)	0.067 (2)
O3	0.3412 (5)	−0.0744 (14)	1.1591 (10)	0.074 (2)
O4	0.2582 (4)	−0.2739 (15)	1.0882 (13)	0.075 (3)
O5	0.0000	−0.0797 (19)	0.3322 (16)	0.087 (4)
O6	0.0000	−0.0874 (16)	0.0909 (12)	0.064 (3)
O7	−0.0587 (6)	−0.2950 (17)	0.2120 (15)	0.101 (5)
O8	0.0000	−0.4529 (12)	0.4711 (12)	0.053 (2)
O9	0.5000	0.2046 (13)	0.7598 (11)	0.050 (2)
O10W	0.3672 (5)	0.2637 (14)	0.9521 (10)	0.069 (2)
H8	0.0000	−0.5106	0.5433	0.079*
H9	0.5000	0.1684	0.6792	0.076*
H10A	0.3245	0.2609	0.9585	0.103*
H10B	0.3880	0.3243	1.0045	0.103*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cd1	0.0500 (4)	0.0507 (5)	0.0522 (4)	0.0020 (2)	−0.0006 (3)	0.0041 (3)
Cd2	0.0531 (5)	0.0410 (5)	0.0483 (5)	0.000	0.000	−0.0009 (4)
Rb	0.0822 (9)	0.0646 (8)	0.0728 (8)	−0.0027 (5)	0.0079 (6)	−0.0081 (6)
S1	0.0447 (9)	0.0488 (12)	0.0489 (11)	−0.0029 (8)	−0.0010 (9)	0.0011 (10)
S2	0.0553 (16)	0.0370 (16)	0.0474 (17)	0.000	0.000	0.0015 (11)
O1	0.068 (4)	0.069 (6)	0.058 (4)	−0.003 (4)	0.001 (4)	0.007 (4)
O2	0.060 (4)	0.056 (4)	0.085 (6)	0.005 (3)	−0.004 (4)	−0.002 (4)
O3	0.078 (5)	0.076 (6)	0.067 (5)	0.016 (5)	−0.020 (5)	−0.015 (5)
O4	0.048 (4)	0.087 (7)	0.090 (6)	−0.011 (4)	0.000 (4)	0.015 (5)
O5	0.151 (13)	0.058 (6)	0.053 (6)	0.000	0.000	−0.004 (7)
O6	0.096 (8)	0.045 (5)	0.051 (6)	0.000	0.000	0.004 (4)
O7	0.095 (7)	0.096 (8)	0.112 (9)	−0.048 (7)	−0.037 (7)	0.048 (7)
O8	0.061 (6)	0.041 (6)	0.055 (6)	0.000	0.000	−0.002 (4)
O9	0.052 (4)	0.046 (5)	0.053 (5)	0.000	0.000	−0.002 (4)
O10W	0.072 (4)	0.066 (5)	0.069 (5)	0.002 (4)	−0.006 (4)	−0.012 (4)

Geometric parameters (Å, º)

Cd1—O3^i	2.241 (9)	S1—O2	1.483 (8)
Cd1—O8^ii	2.270 (8)	S2—O7^x	1.416 (10)
Cd1—O9	2.280 (7)	S2—O7	1.416 (10)
Cd1—O1	2.303 (9)	S2—O5	1.457 (16)
Cd1—O10W	2.343 (10)	S2—O6	1.486 (12)
Cd1—O7^iii	2.352 (11)	O1—Rb^viii	3.134 (10)
Cd2—O8	2.234 (10)	O2—Cd2^ii	2.309 (8)
Cd2—O9^iv	2.262 (11)	O2—Rb^ii	3.141 (11)
Cd2—O6^v	2.280 (13)	O2—Rb^viii	3.235 (11)
Cd2—O2^vi	2.309 (8)	O3—Cd1^xi	2.241 (9)
Cd2—O2^vii	2.309 (8)	O3—Rb^xi	3.146 (11)
Cd2—O5	2.370 (16)	O4—Rb^xi	3.030 (13)
Rb—O10W^viii	2.974 (11)	O4—Rb^ii	3.054 (11)
Rb—O4^i	3.030 (13)	O4—Rb^viii	3.524 (13)
Rb—O4^vi	3.054 (11)	O6—Cd2^xii	2.280 (13)
Rb—O1	3.126 (9)	O7—Cd1^vii	2.352 (11)
Rb—O1^ix	3.134 (10)	O7—Rb^xii	3.360 (16)
Rb—O2^vi	3.141 (11)	O8—Cd1^vi	2.270 (8)
Rb—O3^i	3.146 (11)	O8—Cd1^vii	2.270 (8)
Rb—O2^ix	3.235 (11)	O9—Cd2^xiii	2.262 (11)
S1—O3	1.445 (10)	O9—Cd1^xiv	2.280 (7)
S1—O4	1.452 (9)	O10W—Rb^ix	2.974 (11)
S1—O1	1.474 (9)
O3^i—Cd1—O8^ii	164.5 (4)	O4^i—Rb—O2^ix	121.7 (3)
O3^i—Cd1—O9	96.2 (3)	O4^vi—Rb—O2^ix	155.6 (3)
O8^ii—Cd1—O9	80.1 (3)	O1—Rb—O2^ix	94.8 (2)
O3^i—Cd1—O1	86.6 (3)	O1^ix—Rb—O2^ix	44.6 (2)
O8^ii—Cd1—O1	98.5 (3)	O2^vi—Rb—O2^ix	127.4 (3)
O9—Cd1—O1	173.9 (4)	O3^i—Rb—O2^ix	134.0 (2)
O3^i—Cd1—O10W	93.8 (4)	O3—S1—O4	109.3 (7)
O8^ii—Cd1—O10W	101.1 (4)	O3—S1—O1	109.1 (6)
O9—Cd1—O10W	88.4 (4)	O4—S1—O1	109.7 (6)
O1—Cd1—O10W	86.0 (4)	O3—S1—O2	110.1 (6)
O3^i—Cd1—O7^iii	81.3 (5)	O4—S1—O2	108.6 (6)
O8^ii—Cd1—O7^iii	84.4 (4)	O1—S1—O2	109.9 (6)
O9—Cd1—O7^iii	98.3 (5)	O7^x—S2—O7	104.9 (12)
O1—Cd1—O7^iii	87.4 (5)	O7^x—S2—O5	112.4 (8)
O10W—Cd1—O7^iii	172.0 (4)	O7—S2—O5	112.4 (8)
O8—Cd2—O9^iv	89.4 (4)	O7^x—S2—O6	107.9 (6)
O8—Cd2—O6^v	169.5 (5)	O7—S2—O6	107.9 (6)
O9^iv—Cd2—O6^v	101.0 (4)	O5—S2—O6	111.0 (8)
O8—Cd2—O2^vi	94.9 (2)	S1—O1—Cd1	125.0 (5)
O9^iv—Cd2—O2^vi	89.7 (3)	S1—O1—Rb	127.6 (5)
O6^v—Cd2—O2^vi	85.3 (2)	Cd1—O1—Rb	101.8 (3)
O8—Cd2—O2^vii	94.9 (2)	S1—O1—Rb^viii	90.7 (5)
O9^iv—Cd2—O2^vii	89.7 (3)	Cd1—O1—Rb^viii	110.4 (3)
O6^v—Cd2—O2^vii	85.3 (2)	Rb—O1—Rb^viii	94.2 (2)
O2^vi—Cd2—O2^vii	170.3 (4)	S1—O2—Cd2^ii	130.0 (5)
O8—Cd2—O5	91.6 (5)	S1—O2—Rb^ii	94.1 (5)
O9^iv—Cd2—O5	179.0 (5)	Cd2^ii—O2—Rb^ii	119.9 (4)
O6^v—Cd2—O5	77.9 (5)	S1—O2—Rb^viii	86.7 (5)
O2^vi—Cd2—O5	90.2 (3)	Cd2^ii—O2—Rb^viii	114.6 (4)
O2^vii—Cd2—O5	90.2 (3)	Rb^ii—O2—Rb^viii	105.0 (2)
O10W^viii—Rb—O4^i	171.3 (3)	S1—O3—Cd1^xi	140.3 (6)
O10W^viii—Rb—O4^vi	88.6 (3)	S1—O3—Rb^xi	99.0 (5)
O4^i—Rb—O4^vi	82.7 (3)	Cd1^xi—O3—Rb^xi	102.7 (4)
O10W^viii—Rb—O1	76.1 (3)	S1—O4—Rb^xi	104.0 (6)
O4^i—Rb—O1	102.0 (2)	S1—O4—Rb^ii	98.4 (5)
O4^vi—Rb—O1	76.9 (3)	Rb^xi—O4—Rb^ii	97.8 (4)
O10W^viii—Rb—O1^ix	111.6 (2)	S1—O4—Rb^viii	76.4 (5)
O4^i—Rb—O1^ix	77.2 (3)	Rb^xi—O4—Rb^viii	161.6 (4)
O4^vi—Rb—O1^ix	159.2 (3)	Rb^ii—O4—Rb^viii	100.3 (3)
O1—Rb—O1^ix	102.2 (3)	S2—O5—Cd2	121.2 (9)
O10W^viii—Rb—O2^vi	81.6 (3)	S2—O6—Cd2^xii	133.0 (7)
O4^i—Rb—O2^vi	92.0 (3)	S2—O7—Cd1^vii	132.3 (7)
O4^vi—Rb—O2^vi	45.2 (2)	S2—O7—Rb^xii	102.7 (8)
O1—Rb—O2^vi	118.1 (2)	Cd1^vii—O7—Rb^xii	102.2 (5)
O1^ix—Rb—O2^vi	139.6 (2)	Cd2—O8—Cd1^vi	119.3 (3)
O10W^viii—Rb—O3^i	129.9 (3)	Cd2—O8—Cd1^vii	119.3 (3)
O4^i—Rb—O3^i	45.0 (3)	Cd1^vi—O8—Cd1^vii	95.2 (4)
O4^vi—Rb—O3^i	61.0 (3)	Cd2^xiii—O9—Cd1^xiv	121.4 (3)
O1—Rb—O3^i	59.6 (2)	Cd2^xiii—O9—Cd1	121.4 (3)
O1^ix—Rb—O3^i	100.3 (3)	Cd1^xiv—O9—Cd1	94.7 (4)
O2^vi—Rb—O3^i	98.5 (3)	Cd1—O10W—Rb^ix	115.5 (4)
O10W^viii—Rb—O2^ix	67.1 (2)

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

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O8—H8···O7^xv	0.86	2.56	3.347 (18)	152
O8—H8···O7^xvi	0.86	2.56	3.347 (18)	152
O10W—H10A···O4^ix	0.82	2.07	2.776 (13)	145
O10W—H10B···O6^xvii	0.82	2.42	3.133 (12)	147
O10W—H10B···O6^xviii	0.82	2.42	3.133 (12)	147
O10W—H10B···O7^xvii	0.82	2.51	3.008 (17)	120

Symmetry codes: (ix) −x+1/2, y+1/2, z; (xv) −x, −y−1, z+1/2; (xvi) x, −y−1, z+1/2; (xvii) x+1/2, y+1/2, z+1; (xviii) −x+1/2, y+1/2, z+1.