Ennea-ammonium dibromide tetra­(thio­sulfato)argentate

Crystals of (NH₄)₉Br₂[Ag(S₂O₃)₄] have been found to be isostructural with those of (NH₄)₉Cl₂[Ag(S₂O₃)₄], previously reported by Bigoli, Tiripicchio & Tiripicchio Camellini [Acta Cryst. (1972), B28, 2079-2083].

Key indicators

• Single-crystal X-ray study
• T = 173 K
• Mean [sigma](S-O) = 0.005 Å
• R factor = 0.058
• wR factor = 0.179
• Data-to-parameter ratio = 26.6

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry


 Alert Level A:



DIFF_019  Alert A _diffrn_standards_number is missing
          Number of standards used in measurement.

DIFF_020  Alert A _diffrn_standards_interval_count and
          _diffrn_standards_interval_time are missing. Number of measurements
          between standards or time (min) between standards.


 Alert Level B:



ABSTM_02  Alert B The ratio of expected to reported Tmax/Tmin(RR') is < 0.75
          Tmin and Tmax reported:      0.266     0.495
          Tmin' and Tmax expected:      0.428     0.441
          RR' =      0.552
          Please check that your absorption correction is appropriate.


 Alert Level C:



PLAT_420  Alert C D-H Without Acceptor       N(4)   -   H(4B)             ?

General Notes



ABSTM_02  When printed, the submitted absorption T values will be replaced
          by the scaled T values. Since the ratio of scaled T's is
          identical to the ratio of reported T values, the scaling does
          not imply a change to the absorption corrections used in the
          study.
          Ratio of Tmax expected/reported      0.891
          Tmax scaled      0.441 Tmin scaled      0.237

REFLT_03
         From the CIF: _diffrn_reflns_theta_max           29.58
         From the CIF: _reflns_number_total               2019
         Count of symmetry unique reflns         1134
         Completeness (_total/calc)            178.04%
         TEST3: Check Friedels for noncentro structure
         Estimate of Friedel pairs measured       885
         Fraction of Friedel pairs measured     0.780
         Are heavy atom types Z>Si present          yes
          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.


 2 Alert Level A = Potentially serious problem

 1 Alert Level B = Potential problem

 1 Alert Level C = Please check

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S1. Comment

Alkaline or ammonium thiosulfates are well known as developing agents in photography. Such complexes belong to a general series which can be formulated as M^IX·M^'IX·4M^I₂(S₂O₃)₄, where M^I = NH₄, K, M^'I = Cu, Ag, and X = Cl, Br, I (Ferrari et al., 1952).

The structure of the compound with X = Cl, (NH₄)₉Cl₂[Ag(S₂O₃)₄], has already been determined (Bigoli et al., 1972). The present work deals with the crystal structure of the compound with X = Br, of which crystals were found in solutions during studies of waste photolaboratory solutions. The chemical formula has been confirmed after structure determination to be (NH₄)₉Br₂[Ag(S₂O₃)₄] (Fig. 1). The Cl and the Br compounds are isostructural.

The thiosulfate group adopts an almost tetrahedral conformation (Table 1) and the sulfato group acts as a monodentate ligand, complexing silver. Ag is surrounded by four S₂O₃ groups in a distorded tetrahedral coordination. The projection of the structure onto the a axis is shown in Fig. 2. The crystal structure can be described as a three-dimensional framework composed of [Ag(S₂O₃)₄]₂ pseudo-dimers linked via O···NH₄⁺Br^- interactions. Several hydrogen bonds stabilize the crystal packing (Table 2).

S2. Experimental

Crystals of the title compound were found in solutions during studies of waste photolaboratory solutions.

Computing details

Data collection: X-AREA (Stoe & Cie, 2001); cell refinement: X-AREA; data reduction: X-AREA; program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: XP in SHELXTL-Plus (Sheldrick, 1991).

Figures

	Fig. 1. Perspective view of the title compound with the atom numbering. Displacement ellipsoids are at the 50% probability level.
	Fig. 2. Packing diagram of the title compound, viewed along the a axis, red = Br, blue = NH4, violet = AgS4 and yellow = S2O3.

(I)

Crystal data

(NH4)9Br[Ag(S2O3)4]	Dx = 2.016 Mg m^−3
Mr = 878.55	Mo Kα radiation, λ = 0.71073 Å
Tetragonal, I42d	Cell parameters from 72726 reflections
Hall symbol: I -4 2bw	θ = 2.8–29.7°
a = 13.2634 (7) Å	µ = 4.09 mm^−1
c = 16.4524 (11) Å	T = 173 K
V = 2894.3 (3) Å^3	Block, colourless
Z = 4	0.20 × 0.20 × 0.20 mm
F(000) = 1760

Data collection

Stoe IPDS-II two-circle diffractometer	2019 independent reflections
Radiation source: fine-focus sealed tube	2014 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.049
ω scans	θmax = 29.6°, θmin = 3.1°
Absorption correction: empirical (using intensity measurements) (MULABS; Spek, 1990; Blessing, 1995)	h = −18→17
Tmin = 0.266, Tmax = 0.495	k = −18→18
23871 measured reflections	l = −22→22

Refinement

Refinement on F^2	Hydrogen site location: inferred from neighbouring sites
Least-squares matrix: full	H-atom parameters constrained
R[F^2 > 2σ(F^2)] = 0.058	w = 1/[σ^2(Fo^2) + (0.117P)^2 + 25.2061P] where P = (Fo^2 + 2Fc^2)/3
wR(F^2) = 0.179	(Δ/σ)max < 0.001
S = 1.10	Δρmax = 1.82 e Å^−3
2019 reflections	Δρmin = −2.36 e Å^−3
76 parameters	Extinction correction: SHELXL97, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
0 restraints	Extinction coefficient: 0.0060 (9)
Primary atom site location: structure-invariant direct methods	Absolute structure: Flack (1983)
Secondary atom site location: difference Fourier map	Absolute structure parameter: 0.11 (3)

Special details

Experimental. ;

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
Ag1	1.0000	0.5000	0.2500	0.0246 (3)
S1	0.75466 (11)	0.52067 (10)	0.14848 (9)	0.0230 (3)
S2	0.85780 (12)	0.41288 (12)	0.16837 (11)	0.0287 (4)
O1	0.8017 (4)	0.6066 (4)	0.1080 (3)	0.0373 (12)
O2	0.7116 (4)	0.5525 (5)	0.2270 (3)	0.0368 (12)
O3	0.6739 (4)	0.4777 (4)	0.0979 (4)	0.0407 (13)
Br1	0.50586 (14)	0.2500	0.1250	0.0593 (4)
N1	1.0000	0.5000	−0.2500	0.0271 (18)
H1A	0.9929	0.5562	−0.2187	0.033*
N2	1.0000	0.5000	−0.0136 (7)	0.076 (5)
H2A	0.9593	0.5355	−0.0477	0.092*
H2B	0.9633	0.4579	0.0185	0.092*
N3	0.9561 (6)	−0.2500	0.1250	0.0280 (15)
H3A	0.9159	−0.2035	0.1005	0.034*
H3B	0.9959	−0.2194	0.1627	0.034*
N4	0.7283 (5)	0.1981 (5)	0.2464 (4)	0.0381 (13)
H4A	0.7940	0.1973	0.2622	0.046*
H4B	0.7193	0.2335	0.1996	0.046*
H4C	0.7057	0.1354	0.2332	0.046*
H4D	0.6887	0.2316	0.2826	0.046*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Ag1	0.0221 (3)	0.0221 (3)	0.0297 (4)	0.000	0.000	0.000
S1	0.0197 (6)	0.0181 (6)	0.0312 (7)	−0.0016 (4)	−0.0053 (5)	0.0010 (4)
S2	0.0231 (7)	0.0236 (7)	0.0396 (8)	0.0033 (5)	−0.0084 (6)	−0.0066 (6)
O1	0.034 (2)	0.035 (2)	0.043 (3)	−0.009 (2)	−0.011 (2)	0.018 (2)
O2	0.035 (3)	0.041 (3)	0.035 (3)	0.012 (2)	0.000 (2)	0.002 (2)
O3	0.027 (2)	0.028 (2)	0.067 (4)	−0.0009 (17)	−0.021 (2)	−0.008 (2)
Br1	0.0458 (7)	0.0718 (10)	0.0602 (8)	0.000	0.000	0.0039 (7)
N1	0.025 (3)	0.025 (3)	0.032 (4)	0.000	0.000	0.000
N2	0.156 (17)	0.028 (5)	0.046 (5)	−0.007 (9)	0.000	0.000
N3	0.033 (4)	0.023 (3)	0.029 (3)	0.000	0.000	0.002 (3)
N4	0.031 (3)	0.042 (3)	0.042 (3)	0.008 (2)	0.003 (3)	−0.010 (3)

Geometric parameters (Å, º)

Ag1—S2^i	2.5876 (15)	N2—H2A	0.9100
Ag1—S2^ii	2.5877 (15)	N2—H2B	0.9100
Ag1—S2	2.5877 (15)	N3—H3A	0.9100
Ag1—S2^iii	2.5877 (15)	N3—H3B	0.9101
S1—O1	1.460 (5)	N4—H4A	0.9100
S1—O3	1.471 (5)	N4—H4B	0.9100
S1—O2	1.474 (6)	N4—H4C	0.9100
S1—S2	2.006 (2)	N4—H4D	0.9100
N1—H1A	0.9100
S2^i—Ag1—S2^ii	117.47 (8)	O2—S1—S2	109.0 (2)
S2^i—Ag1—S2	105.63 (4)	S1—S2—Ag1	105.28 (7)
S2^ii—Ag1—S2	105.63 (4)	H2A—N2—H2B	111.0
S2^i—Ag1—S2^iii	105.62 (4)	H3A—N3—H3B	109.9
S2^ii—Ag1—S2^iii	105.62 (4)	H4A—N4—H4B	111.9
S2—Ag1—S2^iii	117.47 (8)	H4A—N4—H4C	111.9
O1—S1—O3	110.8 (3)	H4B—N4—H4C	103.1
O1—S1—O2	110.0 (4)	H4A—N4—H4D	111.9
O3—S1—O2	108.9 (4)	H4B—N4—H4D	103.1
O1—S1—S2	109.8 (2)	H4C—N4—H4D	114.4
O3—S1—S2	108.2 (2)
O1—S1—S2—Ag1	55.6 (3)	S2^i—Ag1—S2—S1	29.27 (6)
O3—S1—S2—Ag1	176.7 (3)	S2^ii—Ag1—S2—S1	154.41 (11)
O2—S1—S2—Ag1	−65.0 (3)	S2^iii—Ag1—S2—S1	−88.16 (8)

Symmetry codes: (i) y+1/2, −x+3/2, −z+1/2; (ii) −y+3/2, x−1/2, −z+1/2; (iii) −x+2, −y+1, z.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1A···O3^iv	0.91	1.92	2.829 (5)	180
N2—H2A···O3^iv	0.91	2.53	3.255 (11)	138
N2—H2A···Br1^v	0.91	3.08	3.789 (6)	136
N2—H2B···O2^vi	0.91	2.36	2.896 (6)	118
N2—H2B···S2	0.91	2.90	3.723 (10)	152
N3—H3A···O1^vii	0.91	2.10	2.808 (8)	134
N3—H3B···O2^viii	0.91	1.97	2.797 (7)	151
N4—H4A···O2^ii	0.91	2.05	2.947 (9)	167
N4—H4B···Br1	0.91	3.09	3.628 (7)	120
N4—H4C···O3^vii	0.91	2.05	2.892 (9)	153
N4—H4D···O1^ix	0.91	1.89	2.805 (8)	180

Symmetry codes: (ii) −y+3/2, x−1/2, −z+1/2; (iv) y+1/2, x, z−1/4; (v) −y+1, x, −z; (vi) −y+3/2, −x+1, z−1/4; (vii) x, −y+1/2, −z+1/4; (viii) y+1/2, −x+1/2, −z+1/2; (ix) y, x−1/2, z+1/4.