Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270102017961/iz1027sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270102017961/iz1027Isup2.hkl | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270102017961/iz1027IIsup3.hkl |
All reagents used were analytical grade. Caesium thiocyanate was synthesized as follows: NH4SCN (13.96 g) was dissolved in deionized water (40.0 g), and in a separate beaker Cs2CO3 (30.0 g; Aldrich Chemical Company Inc.) was also dissolved in deionized water (110.0 g). The solutions were mixed and the mixture was heated with stirring until the smell of ammonia was no longer sensed. The residue was evaporated close to dryness in a water bath with continuous stirring. The CsSCN was dried and stored in a desiccator. Compound (I) was synthesized at room temperature by dissolving NH4SCN (2.05 g; Aldrich Chemical Company Inc.) in deionized water (20.0 g) and then dissolving AgSCN (0.28 g; City Chemical LLC) in the resulting solution. Next, Zn(NCS)2 (1.33 g; City Chemical LLC) and CsSCN (1.75 g) were added. Not all of the Zn(NCS)2 and CsSCN dissolved. The solution was heated with hot tap water for a while, stirred with a glass rod and then filtered. Within 1 d, colourless crystals of (I) formed. Compound (II) was synthesized at room temperature by dissolving Zn(NCS)2 (4.30 g; City Chemical LLC) in deionized water (5.00 g). The solution was filtered to remove turbidity. Another solution was made by dissolving CsSCN (1.10 g) in deionized water (5.00 g) and adding AgSCN (0.13 g; City Chemical LLC) to the resulting solution. Not all of the AgSCN dissolved, and the second solution was filtered to remove the excess AgSCN. These two solutions were mixed and the precipitate which formed immediately was removed by filtration. Within a couple of days, colourless crystals of (II) formed.
The s.u.s of the cell constants of (I) indicate the internal consistency of the measurements themselves, i.e. the precision of the measurement, not their accuracy.
Caesium silver zinc tetrathiocyanate monohydrate has been known for a century (Wells, 1902, 1922), but its anhydrous form, Cs[AgZn(SCN)4], has not been mentioned in the literature till now. Our research indicates that Cs[AgZn(SCN)4] crystallizes in two polymorphic forms, in space groups P21/n, (I), and C2/c, (II). There are a total of four different caesium silver zinc thiocyanates known in the literature, namely Cs[AgZn(SCN)4]·H2O, Cs2[AgZn(SCN)5], Cs[Ag3Zn2(SCN)8] and Cs[Ag4Zn2(SCN)9] (Wells, 1902, 1922; Güneş & Valkonen, 2002a,b). Cs, Ag and Zn all form simple thiocyanates. CsSCN crystallizes in spacegroup Pnma, AgSCN in two polymorphic forms in spacegroups C2/c and Pmnn, and Zn(NCS)2 in spacegroup P1. Also, Zn(NCS)2·2H2O is known in the literature and crystallizes in spacegroup P212121. \sch
Our interest in triple thiocyanates of silver arises from the fact that some of them, such as Cs3Sr[Ag2(SCN)7] and Cs3Ba[Ag2(SCN)7], have been found to have a noncentrosymmetric crystal structure (Bohaty & Fröhlich, 1992). A noncentrosymmetric crystal structure can possess some very interesting optical, electro-optic and electrostrictive properties, which could be utilized in, for example, telecommunications, optical computing, optical information processing, optical-disk data storage, laser remote sensing, laser-driven fusion, colour displays, medical diagnostics, and so on. The idea is based on the capability of these materials to convert IR laser radiation efficiently to visible and UV wavelengths, and especially their highly efficient second harmonic generation of blue-violet light (Wang et al., 2001).
The structure of Cs[AgZn(SCN)4] is very interesting, as it seems to crystallize in two different polymorphic forms. In (I), the structure forms a simple three-dimensional network. The Ag is bonded to four S atoms of four thiocyanate groups, which are then bonded from the other end to Zn atoms (Fig. 1). This simple bonding mode continues throughout the structure, where the Cs atoms further connect the thiocyanate groups through S and N atoms.
The Ag and Zn atoms of (I) are both tetrahedrally coordinated, the Ag surrounded by four S atoms and the Zn by four N atoms. The tetrahedron around Ag is quite strongly distorted, but the tetrahedron around Zn is nearly ideal. The Cs atom is ten-coordinated, being surrounded by five S, three C and two N atoms. The C atoms do not actually participate in bonding but Cs can, by back coordination, form a dihapto (η2) π bond to the triple C≡N bond of a thiocyanate group.
The structure of (II) is slightly more complicated, as it includes an Ag atom disordered over three sites, Ag1, Ag2, Ag3 with occupancies 0.36 (2), 0.26 (2), 0.38 (2) respectively. Only one (Ag3) of the three possible positions of the disordered Ag atom actually has clear four-coordination, which is common for an Ag atom, and the other two possible positions are clearly only three- (Ag1) and two- (Ag2) coordinated. The separations between the three disordered Ag atoms are Ag1—Ag2 0.843 (12), Ag2—Ag3 0.766 (11), Ag3—Ag1 0.775 (9) Å. However, on average, the Ag is in a four-coordinate-like environment and the structure includes a binuclear-like anion (Fig. 2), which can be compared with the binuclear [Ag2(SCN)6]4- anions in K4[Ag2(SCN)6] (Krautscheid & Gerber, 2001), where there are two [Ag(SCN)4] units sharing two common SCN- ligands.
The structure of (II) forms also a three-dimensional network, where the thiocyanate groups of the binuclear-like anion bonded from S to the delocalized Ag atom are bonded from the other end to the four-coordinated Zn atom. One of the thiocyanate groups is not bonded to Ag at all, but from N to the Zn atom and from S only to the Cs atom. The tetrahedron around Zn is very slightly distorted. The Cs atom, which connects the network in all dimensions, is a total of 13-coordinated.
Data collection: COLLECT (Nonius, 1997-2000) for (I); CAD-4 Software (Enraf-Nonius, 1989) for (II). Cell refinement: HKL SCALEPACK (Otwinowski & Minor 1997) for (I); CAD-4 Software for (II). Data reduction: HKL DENZO (Otwinowski & Minor 1997) and SCALEPACK for (I); CAD-4 Software for (II). For both compounds, program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: DIAMOND (Brandenburg, 2000); software used to prepare material for publication: WinGX (Farrugia, 1999).
Cs[AgZn(SCN)4] | F(000) = 992 |
Mr = 538.47 | Dx = 2.636 Mg m−3 |
Monoclinic, P21/n | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2yn | Cell parameters from 13915 reflections |
a = 9.0398 (2) Å | θ = 1.0–24.7° |
b = 16.6679 (4) Å | µ = 6.44 mm−1 |
c = 9.0973 (2) Å | T = 293 K |
β = 98.190 (1)° | Botryoidal, colourless |
V = 1356.75 (5) Å3 | 0.15 × 0.15 × 0.15 mm |
Z = 4 |
Nonius KappaCCD area-detector diffractometer | 1852 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.072 |
Horizonally mounted graphite crystal monochromator | θmax = 24.7°, θmin = 2.4° |
Detector resolution: 9 pixels mm-1 | h = −10→10 |
φ scans | k = −19→19 |
12064 measured reflections | l = −10→10 |
2298 independent reflections |
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.041 | w = 1/[σ2(Fo2) + (0.0287P)2 + 7.9708P] where P = (Fo2 + 2Fc2)/3 |
wR(F2) = 0.101 | (Δ/σ)max < 0.001 |
S = 1.04 | Δρmax = 1.86 e Å−3 |
2298 reflections | Δρmin = −1.76 e Å−3 |
137 parameters | Extinction correction: SHELXL97 (Sheldrick, 1997), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
0 restraints | Extinction coefficient: 0.0017 (3) |
Cs[AgZn(SCN)4] | V = 1356.75 (5) Å3 |
Mr = 538.47 | Z = 4 |
Monoclinic, P21/n | Mo Kα radiation |
a = 9.0398 (2) Å | µ = 6.44 mm−1 |
b = 16.6679 (4) Å | T = 293 K |
c = 9.0973 (2) Å | 0.15 × 0.15 × 0.15 mm |
β = 98.190 (1)° |
Nonius KappaCCD area-detector diffractometer | 1852 reflections with I > 2σ(I) |
12064 measured reflections | Rint = 0.072 |
2298 independent reflections |
R[F2 > 2σ(F2)] = 0.041 | 137 parameters |
wR(F2) = 0.101 | 0 restraints |
S = 1.04 | Δρmax = 1.86 e Å−3 |
2298 reflections | Δρmin = −1.76 e Å−3 |
Experimental. Multiscan absorption correction [Blessing, R. H. (1995). Acta Cryst. A51, 33–38] was performed but not applied. The absorption correction was found to have no significant effect on the refinement results. Original values _exptl_absorpt_correction_T_min 0.4601 _exptl_absorpt_correction_T_max 0.5443 |
x | y | z | Uiso*/Ueq | ||
Ag1 | 0.07831 (8) | 0.73943 (4) | 0.84108 (9) | 0.0740 (3) | |
Cs1 | 0.10708 (7) | 0.62465 (5) | 0.35534 (8) | 0.0854 (3) | |
Zn1 | 0.59170 (9) | 0.55282 (5) | 0.78725 (9) | 0.0446 (3) | |
S1 | 0.7147 (2) | 0.62710 (11) | 0.3231 (2) | 0.0476 (5) | |
S2 | 0.0707 (2) | 0.59366 (12) | 0.7472 (3) | 0.0606 (6) | |
S3 | 0.8999 (3) | 0.74826 (13) | 1.0501 (2) | 0.0588 (5) | |
S4 | 0.6481 (3) | 0.28110 (12) | 0.9130 (2) | 0.0605 (6) | |
C1 | 0.6834 (7) | 0.5895 (4) | 0.4815 (8) | 0.0427 (16) | |
C2 | 0.2513 (8) | 0.5819 (4) | 0.7568 (8) | 0.0424 (16) | |
C3 | 0.7876 (8) | 0.6795 (4) | 0.9696 (8) | 0.0459 (17) | |
C4 | 0.6380 (8) | 0.3765 (5) | 0.8828 (7) | 0.0440 (16) | |
N1 | 0.6612 (8) | 0.5620 (4) | 0.5918 (8) | 0.0640 (18) | |
N2 | 0.3773 (8) | 0.5739 (4) | 0.7614 (7) | 0.0530 (15) | |
N3 | 0.7052 (8) | 0.6324 (4) | 0.9124 (8) | 0.0611 (17) | |
N4 | 0.6376 (7) | 0.4441 (4) | 0.8593 (7) | 0.0574 (17) |
U11 | U22 | U33 | U12 | U13 | U23 | |
Ag1 | 0.0744 (5) | 0.0433 (4) | 0.1114 (6) | −0.0092 (3) | 0.0374 (4) | −0.0145 (3) |
Cs1 | 0.0593 (4) | 0.1161 (6) | 0.0834 (5) | −0.0081 (3) | 0.0182 (3) | 0.0110 (4) |
Zn1 | 0.0468 (5) | 0.0385 (5) | 0.0491 (5) | −0.0015 (4) | 0.0093 (4) | 0.0030 (4) |
S1 | 0.0530 (11) | 0.0465 (10) | 0.0451 (10) | 0.0044 (8) | 0.0130 (8) | −0.0038 (8) |
S2 | 0.0457 (11) | 0.0469 (11) | 0.0872 (16) | 0.0025 (9) | 0.0030 (10) | −0.0149 (10) |
S3 | 0.0654 (13) | 0.0599 (13) | 0.0518 (12) | −0.0159 (10) | 0.0109 (9) | −0.0133 (9) |
S4 | 0.0680 (13) | 0.0399 (11) | 0.0689 (14) | 0.0022 (9) | −0.0060 (10) | 0.0112 (9) |
C1 | 0.036 (4) | 0.039 (4) | 0.053 (4) | 0.002 (3) | 0.006 (3) | −0.004 (3) |
C2 | 0.050 (4) | 0.032 (4) | 0.045 (4) | 0.003 (3) | 0.005 (3) | −0.002 (3) |
C3 | 0.050 (4) | 0.047 (4) | 0.044 (4) | 0.004 (4) | 0.016 (3) | 0.000 (3) |
C4 | 0.045 (4) | 0.048 (5) | 0.037 (4) | 0.002 (3) | −0.001 (3) | 0.004 (3) |
N1 | 0.068 (5) | 0.073 (5) | 0.053 (4) | −0.005 (4) | 0.017 (3) | 0.005 (4) |
N2 | 0.055 (4) | 0.044 (4) | 0.061 (4) | 0.002 (3) | 0.011 (3) | −0.001 (3) |
N3 | 0.067 (4) | 0.062 (4) | 0.056 (4) | −0.013 (4) | 0.013 (3) | −0.008 (3) |
N4 | 0.060 (4) | 0.043 (4) | 0.064 (4) | 0.000 (3) | −0.006 (3) | 0.009 (3) |
Ag1—S1i | 2.5600 (19) | Zn1—N2 | 1.951 (7) |
Ag1—S2 | 2.573 (2) | Zn1—N1 | 1.975 (7) |
Ag1—S3ii | 2.667 (2) | S1—C1 | 1.633 (8) |
Ag1—S4iii | 2.944 (2) | S1—Ag1viii | 2.5600 (19) |
Cs1—C4iv | 3.380 (7) | S1—Cs1ix | 3.517 (2) |
Cs1—N4iv | 3.426 (7) | S2—C2 | 1.634 (8) |
Cs1—S1ii | 3.517 (2) | S3—C3 | 1.634 (8) |
Cs1—S3v | 3.647 (2) | S3—Ag1ix | 2.667 (2) |
Cs1—S2 | 3.663 (3) | S3—Cs1x | 3.647 (2) |
Cs1—C3v | 3.730 (7) | S4—C4 | 1.614 (8) |
Cs1—S3vi | 3.739 (2) | S4—Ag1xi | 2.944 (2) |
Cs1—N1iv | 3.743 (8) | C1—N1 | 1.146 (9) |
Cs1—C2 | 3.767 (7) | C2—N2 | 1.141 (9) |
Cs1—S4iv | 3.855 (2) | C3—N3 | 1.153 (10) |
Cs1—S2vii | 4.033 (2) | C3—Cs1x | 3.730 (7) |
Zn1—N3 | 1.943 (7) | C4—N4 | 1.148 (9) |
Zn1—N4 | 1.951 (7) | ||
S1i—Ag1—S2 | 142.15 (7) | S3v—Cs1—S2vii | 150.95 (5) |
S1i—Ag1—S3ii | 110.08 (6) | S2—Cs1—S2vii | 90.56 (5) |
S2—Ag1—S3ii | 107.38 (7) | C3v—Cs1—S2vii | 176.39 (13) |
S1i—Ag1—S4iii | 91.83 (6) | S3vi—Cs1—S2vii | 100.63 (5) |
S2—Ag1—S4iii | 88.83 (7) | C2—Cs1—S2vii | 97.19 (11) |
S3ii—Ag1—S4iii | 97.09 (7) | S4iv—Cs1—S2vii | 117.84 (5) |
C4iv—Cs1—S1ii | 135.90 (12) | N3—Zn1—N4 | 111.6 (3) |
N4iv—Cs1—S1ii | 135.19 (11) | N3—Zn1—N2 | 112.3 (3) |
C4iv—Cs1—S3v | 78.50 (13) | N4—Zn1—N2 | 111.6 (3) |
N4iv—Cs1—S3v | 88.28 (12) | N3—Zn1—N1 | 105.4 (3) |
S1ii—Cs1—S3v | 133.42 (5) | N4—Zn1—N1 | 107.1 (3) |
C4iv—Cs1—S2 | 141.88 (12) | N2—Zn1—N1 | 108.4 (3) |
N4iv—Cs1—S2 | 131.96 (11) | C1—S1—Ag1viii | 97.5 (2) |
S1ii—Cs1—S2 | 81.59 (4) | C1—S1—Cs1ix | 102.8 (2) |
S3v—Cs1—S2 | 76.62 (5) | Ag1viii—S1—Cs1ix | 119.60 (7) |
C4iv—Cs1—C3v | 82.66 (17) | C2—S2—Ag1 | 96.7 (2) |
N4iv—Cs1—C3v | 98.52 (15) | C2—S2—Cs1 | 80.9 (3) |
S1ii—Cs1—C3v | 114.14 (12) | Ag1—S2—Cs1 | 100.84 (7) |
S2—Cs1—C3v | 87.06 (11) | C2—S2—Cs1vii | 105.5 (2) |
C4iv—Cs1—S3vi | 80.93 (12) | Ag1—S2—Cs1vii | 156.86 (8) |
N4iv—Cs1—S3vi | 93.90 (11) | Cs1—S2—Cs1vii | 89.44 (5) |
S1ii—Cs1—S3vi | 62.56 (5) | C3—S3—Ag1ix | 92.4 (2) |
S3v—Cs1—S3vi | 107.03 (2) | C3—S3—Cs1x | 80.1 (3) |
S2—Cs1—S3vi | 134.07 (5) | Ag1ix—S3—Cs1x | 98.99 (7) |
C3v—Cs1—S3vi | 82.97 (12) | C3—S3—Cs1xii | 99.2 (3) |
C4iv—Cs1—N1iv | 69.98 (16) | Ag1ix—S3—Cs1xii | 102.08 (7) |
S1ii—Cs1—N1iv | 124.02 (12) | Cs1x—S3—Cs1xii | 158.92 (7) |
S3v—Cs1—N1iv | 93.80 (12) | C4—S4—Ag1xi | 94.7 (3) |
S2—Cs1—N1iv | 83.33 (11) | C4—S4—Cs1iv | 61.0 (3) |
C3v—Cs1—N1iv | 118.49 (17) | Ag1xi—S4—Cs1iv | 89.81 (6) |
S3vi—Cs1—N1iv | 139.94 (11) | N1—C1—S1 | 179.0 (7) |
C4iv—Cs1—C2 | 116.55 (16) | N2—C2—S2 | 179.0 (7) |
N4iv—Cs1—C2 | 108.73 (15) | N2—C2—Cs1 | 105.3 (5) |
S1ii—Cs1—C2 | 106.78 (12) | S2—C2—Cs1 | 73.8 (3) |
S3v—Cs1—C2 | 60.77 (11) | N3—C3—S3 | 178.1 (7) |
C3v—Cs1—C2 | 79.52 (15) | N3—C3—Cs1x | 103.9 (6) |
S3vi—Cs1—C2 | 153.09 (11) | S3—C3—Cs1x | 74.4 (3) |
N1iv—Cs1—C2 | 66.94 (15) | N4—C4—S4 | 176.7 (7) |
N4iv—Cs1—S4iv | 44.06 (11) | N4—C4—Cs1iv | 82.6 (5) |
S1ii—Cs1—S4iv | 127.26 (5) | S4—C4—Cs1iv | 94.4 (3) |
S3v—Cs1—S4iv | 68.20 (5) | C1—N1—Zn1 | 159.5 (7) |
S2—Cs1—S4iv | 144.37 (5) | C1—N1—Cs1iv | 106.3 (5) |
C3v—Cs1—S4iv | 63.39 (11) | Zn1—N1—Cs1iv | 93.7 (3) |
S3vi—Cs1—S4iv | 65.00 (5) | C2—N2—Zn1 | 174.0 (6) |
N1iv—Cs1—S4iv | 93.37 (11) | C3—N3—Zn1 | 169.0 (6) |
C2—Cs1—S4iv | 122.71 (12) | C4—N4—Zn1 | 165.9 (6) |
C4iv—Cs1—S2vii | 97.61 (13) | C4—N4—Cs1iv | 78.0 (5) |
N4iv—Cs1—S2vii | 81.08 (12) | Zn1—N4—Cs1iv | 104.3 (3) |
S1ii—Cs1—S2vii | 68.12 (4) |
Symmetry codes: (i) x−1/2, −y+3/2, z+1/2; (ii) x−1, y, z; (iii) −x+1/2, y+1/2, −z+3/2; (iv) −x+1, −y+1, −z+1; (v) x−1/2, −y+3/2, z−1/2; (vi) x−1, y, z−1; (vii) −x, −y+1, −z+1; (viii) x+1/2, −y+3/2, z−1/2; (ix) x+1, y, z; (x) x+1/2, −y+3/2, z+1/2; (xi) −x+1/2, y−1/2, −z+3/2; (xii) x+1, y, z+1. |
Cs[AgZn(SCN)4] | F(000) = 1984 |
Mr = 538.47 | Dx = 2.806 Mg m−3 |
Monoclinic, C2/c | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -C 2yc | Cell parameters from 25 reflections |
a = 13.964 (2) Å | θ = 4.4–12.5° |
b = 14.851 (2) Å | µ = 6.86 mm−1 |
c = 13.389 (2) Å | T = 293 K |
β = 113.35 (1)° | Rod, colourless |
V = 2549.2 (7) Å3 | 0.20 × 0.05 × 0.05 mm |
Z = 8 |
Nonius MACH3 diffractometer | 1447 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.084 |
Graphite monochromator | θmax = 30.0°, θmin = 3.0° |
ω/2θ scans | h = −19→19 |
Absorption correction: ψ scan (North et al., 1968) | k = −20→20 |
Tmin = 0.579, Tmax = 0.710 | l = −18→18 |
7410 measured reflections | 3 standard reflections every 60 min |
3705 independent reflections | intensity decay: 0.8% |
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.060 | w = 1/[σ2(Fo2) + (0.0374P)2] where P = (Fo2 + 2Fc2)/3 |
wR(F2) = 0.119 | (Δ/σ)max < 0.001 |
S = 0.94 | Δρmax = 0.67 e Å−3 |
3705 reflections | Δρmin = −0.78 e Å−3 |
155 parameters | Extinction correction: SHELXL97 (Sheldrick, 1997), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
0 restraints | Extinction coefficient: 0.00018 (4) |
Cs[AgZn(SCN)4] | V = 2549.2 (7) Å3 |
Mr = 538.47 | Z = 8 |
Monoclinic, C2/c | Mo Kα radiation |
a = 13.964 (2) Å | µ = 6.86 mm−1 |
b = 14.851 (2) Å | T = 293 K |
c = 13.389 (2) Å | 0.20 × 0.05 × 0.05 mm |
β = 113.35 (1)° |
Nonius MACH3 diffractometer | 1447 reflections with I > 2σ(I) |
Absorption correction: ψ scan (North et al., 1968) | Rint = 0.084 |
Tmin = 0.579, Tmax = 0.710 | 3 standard reflections every 60 min |
7410 measured reflections | intensity decay: 0.8% |
3705 independent reflections |
R[F2 > 2σ(F2)] = 0.060 | 155 parameters |
wR(F2) = 0.119 | 0 restraints |
S = 0.94 | Δρmax = 0.67 e Å−3 |
3705 reflections | Δρmin = −0.78 e Å−3 |
Experimental. For the absorption correction: Number of ψ-scan sets used was 3. Theta correction was applied. Averaged transmission function was used. No Fourier smoothing was applied. |
x | y | z | Uiso*/Ueq | Occ. (<1) | |
Ag1 | −0.0768 (6) | 0.4945 (3) | 0.1098 (4) | 0.0850 (14) | 0.36 (2) |
Ag2 | −0.1285 (6) | 0.4878 (5) | 0.0490 (10) | 0.102 (2) | 0.26 (2) |
Ag3 | −0.0721 (4) | 0.4932 (3) | 0.0545 (6) | 0.0694 (12) | 0.38 (3) |
Cs1 | 0.13009 (5) | 0.16177 (5) | 0.15826 (6) | 0.0775 (3) | |
Zn1 | 0.38575 (7) | 0.33058 (6) | 0.31512 (7) | 0.0445 (3) | |
S1 | 0.3410 (2) | 0.14476 (16) | 0.01544 (19) | 0.0755 (8) | |
S2 | 0.4008 (2) | 0.16715 (16) | 0.6190 (2) | 0.0711 (7) | |
S3 | 0.11573 (19) | 0.54139 (16) | 0.1738 (2) | 0.0743 (8) | |
S4 | 0.63549 (19) | 0.55862 (16) | 0.4191 (2) | 0.0700 (7) | |
C1 | 0.3674 (5) | 0.2051 (5) | 0.1246 (7) | 0.0366 (18) | |
C2 | 0.3882 (6) | 0.2164 (5) | 0.5048 (7) | 0.042 (2) | |
C3 | 0.1967 (6) | 0.4576 (6) | 0.2197 (6) | 0.044 (2) | |
C4 | 0.5574 (6) | 0.4734 (6) | 0.3920 (6) | 0.045 (2) | |
N1 | 0.3802 (5) | 0.2493 (4) | 0.1978 (5) | 0.0463 (18) | |
N2 | 0.3810 (7) | 0.2527 (4) | 0.4299 (7) | 0.072 (3) | |
N3 | 0.2572 (6) | 0.4016 (5) | 0.2523 (5) | 0.0579 (19) | |
N4 | 0.5027 (6) | 0.4127 (5) | 0.3762 (6) | 0.060 (2) |
U11 | U22 | U33 | U12 | U13 | U23 | |
Ag1 | 0.092 (4) | 0.0418 (14) | 0.137 (4) | 0.0003 (18) | 0.062 (4) | −0.003 (3) |
Ag2 | 0.158 (7) | 0.034 (2) | 0.112 (7) | 0.007 (4) | 0.052 (6) | 0.009 (3) |
Ag3 | 0.076 (3) | 0.0406 (14) | 0.076 (3) | 0.0116 (17) | 0.015 (2) | −0.0047 (17) |
Cs1 | 0.0517 (4) | 0.0887 (5) | 0.0905 (5) | −0.0022 (3) | 0.0265 (3) | 0.0262 (4) |
Zn1 | 0.0572 (6) | 0.0309 (5) | 0.0429 (5) | 0.0003 (5) | 0.0173 (5) | 0.0008 (4) |
S1 | 0.105 (2) | 0.0550 (14) | 0.0451 (14) | 0.0266 (14) | 0.0074 (14) | −0.0104 (12) |
S2 | 0.120 (2) | 0.0471 (13) | 0.0518 (14) | −0.0037 (14) | 0.0400 (15) | 0.0054 (12) |
S3 | 0.0591 (16) | 0.0415 (13) | 0.108 (2) | 0.0117 (12) | 0.0176 (15) | −0.0055 (14) |
S4 | 0.0658 (16) | 0.0474 (13) | 0.099 (2) | −0.0106 (12) | 0.0355 (15) | −0.0165 (14) |
C1 | 0.033 (4) | 0.027 (4) | 0.047 (5) | −0.002 (3) | 0.013 (4) | 0.000 (4) |
C2 | 0.049 (5) | 0.023 (4) | 0.055 (6) | 0.001 (4) | 0.023 (5) | −0.003 (4) |
C3 | 0.044 (5) | 0.058 (5) | 0.036 (5) | −0.002 (4) | 0.022 (4) | 0.003 (4) |
C4 | 0.048 (5) | 0.053 (5) | 0.031 (5) | 0.007 (4) | 0.014 (4) | −0.015 (4) |
N1 | 0.055 (4) | 0.035 (4) | 0.046 (5) | −0.003 (3) | 0.017 (4) | −0.007 (4) |
N2 | 0.126 (8) | 0.033 (4) | 0.067 (6) | 0.013 (4) | 0.050 (6) | 0.009 (4) |
N3 | 0.068 (5) | 0.069 (5) | 0.040 (4) | 0.024 (4) | 0.025 (4) | 0.015 (4) |
N4 | 0.064 (5) | 0.057 (5) | 0.060 (5) | −0.015 (4) | 0.024 (4) | −0.016 (4) |
Ag1—Ag2 | 0.853 (9) | Cs1—S3iv | 3.811 (3) |
Ag2—Ag3 | 0.766 (10) | Cs1—S1vi | 3.817 (3) |
Ag1—Ag3 | 0.770 (5) | Cs1—C3iv | 3.819 (8) |
Ag1—S2i | 2.430 (5) | Cs1—N2i | 3.825 (8) |
Ag1—S3 | 2.573 (8) | Cs1—C4i | 3.861 (8) |
Ag1—S1ii | 2.598 (6) | Zn1—N4 | 1.940 (7) |
Ag2—S1ii | 2.381 (8) | Zn1—N2 | 1.945 (8) |
Ag2—S2i | 2.457 (8) | Zn1—N1 | 1.958 (7) |
Ag3—S1ii | 2.512 (5) | Zn1—N3 | 1.961 (7) |
Ag3—S3 | 2.573 (7) | S1—C1 | 1.627 (9) |
Ag3—S2i | 2.612 (6) | S2—C2 | 1.640 (9) |
Ag3—S3iii | 2.916 (8) | S2—Cs1vii | 3.955 (3) |
Cs1—N1 | 3.564 (7) | S3—C3 | 1.628 (9) |
Cs1—C1 | 3.575 (7) | S4—C4 | 1.615 (9) |
Cs1—N4i | 3.651 (8) | C1—N1 | 1.133 (9) |
Cs1—C2i | 3.662 (8) | C2—N2 | 1.108 (9) |
Cs1—C4iv | 3.706 (8) | C3—N3 | 1.142 (9) |
Cs1—S4iv | 3.759 (3) | C4—N4 | 1.146 (9) |
Cs1—S4v | 3.787 (3) | ||
S2i—Ag1—S3 | 112.9 (3) | C3iv—Cs1—C4i | 82.67 (18) |
S2i—Ag1—S1ii | 146.3 (3) | N2i—Cs1—C4i | 67.13 (17) |
S3—Ag1—S1ii | 97.6 (2) | N4—Zn1—N2 | 109.1 (3) |
S1ii—Ag2—S2i | 168.4 (7) | N4—Zn1—N1 | 119.0 (3) |
S1ii—Ag3—S3 | 99.8 (2) | N2—Zn1—N1 | 105.3 (3) |
S1ii—Ag3—S2i | 139.8 (2) | N4—Zn1—N3 | 108.5 (3) |
S3—Ag3—S2i | 107.1 (2) | N2—Zn1—N3 | 110.3 (3) |
S1ii—Ag3—S3iii | 93.3 (2) | N1—Zn1—N3 | 104.5 (3) |
S3—Ag3—S3iii | 116.00 (19) | C1—S1—Ag2viii | 114.2 (4) |
S2i—Ag3—S3iii | 100.9 (2) | C1—S1—Ag3viii | 112.8 (3) |
N1—Cs1—N4i | 108.13 (16) | C1—S1—Ag1viii | 97.9 (3) |
C1—Cs1—N4i | 91.15 (18) | C1—S1—Cs1vi | 95.3 (3) |
N1—Cs1—C2i | 122.35 (15) | Ag2viii—S1—Cs1vi | 142.9 (4) |
C1—Cs1—C2i | 122.37 (16) | Ag3viii—S1—Cs1vi | 129.92 (17) |
N4i—Cs1—C2i | 66.82 (18) | Ag1viii—S1—Cs1vi | 144.1 (2) |
N1—Cs1—C4iv | 151.92 (18) | C1—S1—Cs1 | 59.8 (3) |
C1—Cs1—C4iv | 137.41 (18) | Ag2viii—S1—Cs1 | 94.6 (4) |
N4i—Cs1—C4iv | 64.15 (16) | Ag3viii—S1—Cs1 | 109.59 (16) |
C2i—Cs1—C4iv | 80.97 (18) | Ag1viii—S1—Cs1 | 94.99 (19) |
N1—Cs1—S4iv | 172.44 (12) | Cs1vi—S1—Cs1 | 120.41 (6) |
C1—Cs1—S4iv | 154.30 (14) | C2—S2—Ag1vii | 111.2 (3) |
N4i—Cs1—S4iv | 64.42 (13) | C2—S2—Ag2vii | 97.0 (4) |
C2i—Cs1—S4iv | 57.09 (12) | C2—S2—Ag3vii | 94.2 (3) |
N1—Cs1—S4v | 110.51 (11) | C2—S2—Cs1vii | 67.7 (3) |
C1—Cs1—S4v | 120.56 (13) | Ag1vii—S2—Cs1vii | 121.8 (2) |
N4i—Cs1—S4v | 130.92 (12) | Ag2vii—S2—Cs1vii | 131.0 (3) |
C2i—Cs1—S4v | 113.21 (14) | Ag3vii—S2—Cs1vii | 114.45 (13) |
C4iv—Cs1—S4v | 67.45 (12) | C2—S2—Cs1ix | 113.7 (3) |
S4iv—Cs1—S4v | 75.30 (7) | Ag1vii—S2—Cs1ix | 135.02 (16) |
N1—Cs1—S3iv | 56.95 (10) | Ag2vii—S2—Cs1ix | 144.5 (4) |
C1—Cs1—S3iv | 57.70 (12) | Ag3vii—S2—Cs1ix | 152.06 (18) |
N4i—Cs1—S3iv | 115.23 (12) | Cs1vii—S2—Cs1ix | 79.46 (5) |
C2i—Cs1—S3iv | 177.91 (15) | C3—S3—Ag1 | 113.3 (3) |
C4iv—Cs1—S3iv | 100.29 (14) | C3—S3—Ag3 | 113.9 (3) |
S4iv—Cs1—S3iv | 123.91 (6) | C3—S3—Ag3iii | 94.9 (3) |
S4v—Cs1—S3iv | 65.97 (6) | Ag1—S3—Ag3iii | 81.15 (17) |
N1—Cs1—S1vi | 58.80 (11) | Ag3—S3—Ag3iii | 64.00 (19) |
C1—Cs1—S1vi | 57.35 (12) | C3—S3—Cs1x | 78.0 (3) |
N4i—Cs1—S1vi | 73.96 (12) | Ag1—S3—Cs1x | 158.35 (16) |
C2i—Cs1—S1vi | 65.36 (13) | Ag3—S3—Cs1x | 168.09 (13) |
C4iv—Cs1—S1vi | 134.05 (13) | Ag3iii—S3—Cs1x | 117.39 (13) |
S4iv—Cs1—S1vi | 118.03 (6) | C4—S4—Cs1x | 75.7 (3) |
S4v—Cs1—S1vi | 153.91 (6) | C4—S4—Cs1xi | 110.1 (3) |
S3iv—Cs1—S1vi | 114.44 (6) | Cs1x—S4—Cs1xi | 85.64 (6) |
N1—Cs1—C3iv | 78.96 (16) | N1—C1—S1 | 176.0 (7) |
C1—Cs1—C3iv | 74.64 (17) | N1—C1—Cs1 | 80.3 (5) |
N4i—Cs1—C3iv | 99.70 (17) | S1—C1—Cs1 | 97.0 (3) |
C2i—Cs1—C3iv | 156.88 (18) | N2—C2—S2 | 177.2 (8) |
C4iv—Cs1—C3iv | 76.14 (19) | N2—C2—Cs1vii | 89.9 (6) |
S4iv—Cs1—C3iv | 100.54 (14) | S2—C2—Cs1vii | 87.8 (3) |
S4v—Cs1—C3iv | 60.43 (12) | N3—C3—S3 | 176.7 (8) |
S1vi—Cs1—C3iv | 131.01 (13) | N3—C3—Cs1x | 99.6 (6) |
N1—Cs1—N2i | 121.66 (15) | S3—C3—Cs1x | 77.4 (3) |
C1—Cs1—N2i | 115.73 (17) | N4—C4—S4 | 177.8 (8) |
N4i—Cs1—N2i | 50.03 (16) | N4—C4—Cs1x | 100.9 (6) |
C4iv—Cs1—N2i | 75.66 (16) | S4—C4—Cs1x | 79.4 (3) |
S4iv—Cs1—N2i | 55.23 (11) | N4—C4—Cs1vii | 70.9 (6) |
S4v—Cs1—N2i | 123.44 (13) | S4—C4—Cs1vii | 107.0 (3) |
S3iv—Cs1—N2i | 165.14 (13) | Cs1x—C4—Cs1vii | 117.9 (2) |
S1vi—Cs1—N2i | 62.96 (12) | C1—N1—Zn1 | 173.3 (7) |
C3iv—Cs1—N2i | 145.78 (17) | C1—N1—Cs1 | 81.4 (5) |
N1—Cs1—C4i | 102.14 (16) | Zn1—N1—Cs1 | 93.9 (2) |
C1—Cs1—C4i | 83.96 (18) | C2—N2—Zn1 | 170.3 (8) |
N4i—Cs1—C4i | 17.26 (14) | C2—N2—Cs1vii | 73.2 (6) |
C2i—Cs1—C4i | 83.83 (19) | Zn1—N2—Cs1vii | 97.4 (3) |
C4iv—Cs1—C4i | 62.1 (2) | C3—N3—Zn1 | 165.6 (7) |
S4iv—Cs1—C4i | 70.35 (12) | C4—N4—Zn1 | 163.9 (8) |
S4v—Cs1—C4i | 122.90 (12) | C4—N4—Cs1vii | 91.8 (6) |
S3iv—Cs1—C4i | 98.24 (14) | Zn1—N4—Cs1vii | 103.2 (3) |
S1vi—Cs1—C4i | 83.19 (12) |
Symmetry codes: (i) x−1/2, −y+1/2, z−1/2; (ii) x−1/2, y+1/2, z; (iii) −x, −y+1, −z; (iv) −x+1/2, y−1/2, −z+1/2; (v) x−1/2, y−1/2, z; (vi) −x+1/2, −y+1/2, −z; (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+1; (x) −x+1/2, y+1/2, −z+1/2; (xi) x+1/2, y+1/2, z. |
Experimental details
(I) | (II) | |
Crystal data | ||
Chemical formula | Cs[AgZn(SCN)4] | Cs[AgZn(SCN)4] |
Mr | 538.47 | 538.47 |
Crystal system, space group | Monoclinic, P21/n | Monoclinic, C2/c |
Temperature (K) | 293 | 293 |
a, b, c (Å) | 9.0398 (2), 16.6679 (4), 9.0973 (2) | 13.964 (2), 14.851 (2), 13.389 (2) |
β (°) | 98.190 (1) | 113.35 (1) |
V (Å3) | 1356.75 (5) | 2549.2 (7) |
Z | 4 | 8 |
Radiation type | Mo Kα | Mo Kα |
µ (mm−1) | 6.44 | 6.86 |
Crystal size (mm) | 0.15 × 0.15 × 0.15 | 0.20 × 0.05 × 0.05 |
Data collection | ||
Diffractometer | Nonius KappaCCD area-detector | Nonius MACH3 |
Absorption correction | – | ψ scan (North et al., 1968) |
Tmin, Tmax | – | 0.579, 0.710 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 12064, 2298, 1852 | 7410, 3705, 1447 |
Rint | 0.072 | 0.084 |
(sin θ/λ)max (Å−1) | 0.587 | 0.703 |
Refinement | ||
R[F2 > 2σ(F2)], wR(F2), S | 0.041, 0.101, 1.04 | 0.060, 0.119, 0.94 |
No. of reflections | 2298 | 3705 |
No. of parameters | 137 | 155 |
Δρmax, Δρmin (e Å−3) | 1.86, −1.76 | 0.67, −0.78 |
Computer programs: COLLECT (Nonius, 1997-2000), CAD-4 Software (Enraf-Nonius, 1989), HKL SCALEPACK (Otwinowski & Minor 1997), CAD-4 Software, HKL DENZO (Otwinowski & Minor 1997) and SCALEPACK, SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), DIAMOND (Brandenburg, 2000), WinGX (Farrugia, 1999).
Ag1—S1i | 2.5600 (19) | S1—C1 | 1.633 (8) |
Ag1—S2 | 2.573 (2) | S2—C2 | 1.634 (8) |
Ag1—S3ii | 2.667 (2) | S3—C3 | 1.634 (8) |
Ag1—S4iii | 2.944 (2) | S4—C4 | 1.614 (8) |
Zn1—N3 | 1.943 (7) | C1—N1 | 1.146 (9) |
Zn1—N4 | 1.951 (7) | C2—N2 | 1.141 (9) |
Zn1—N2 | 1.951 (7) | C3—N3 | 1.153 (10) |
Zn1—N1 | 1.975 (7) | C4—N4 | 1.148 (9) |
S1i—Ag1—S2 | 142.15 (7) | N4—Zn1—N2 | 111.6 (3) |
S1i—Ag1—S3ii | 110.08 (6) | N3—Zn1—N1 | 105.4 (3) |
S2—Ag1—S3ii | 107.38 (7) | N4—Zn1—N1 | 107.1 (3) |
S1i—Ag1—S4iii | 91.83 (6) | N2—Zn1—N1 | 108.4 (3) |
S2—Ag1—S4iii | 88.83 (7) | N1—C1—S1 | 179.0 (7) |
S3ii—Ag1—S4iii | 97.09 (7) | N2—C2—S2 | 179.0 (7) |
N3—Zn1—N4 | 111.6 (3) | N3—C3—S3 | 178.1 (7) |
N3—Zn1—N2 | 112.3 (3) | N4—C4—S4 | 176.7 (7) |
Symmetry codes: (i) x−1/2, −y+3/2, z+1/2; (ii) x−1, y, z; (iii) −x+1/2, y+1/2, −z+3/2. |
Ag1—S2i | 2.430 (5) | Zn1—N1 | 1.958 (7) |
Ag1—S3 | 2.573 (8) | Zn1—N3 | 1.961 (7) |
Ag1—S1ii | 2.598 (6) | S1—C1 | 1.627 (9) |
Ag2—S1ii | 2.381 (8) | S2—C2 | 1.640 (9) |
Ag2—S2i | 2.457 (8) | S3—C3 | 1.628 (9) |
Ag3—S1ii | 2.512 (5) | S4—C4 | 1.615 (9) |
Ag3—S3 | 2.573 (7) | C1—N1 | 1.133 (9) |
Ag3—S2i | 2.612 (6) | C2—N2 | 1.108 (9) |
Ag3—S3iii | 2.916 (8) | C3—N3 | 1.142 (9) |
Zn1—N4 | 1.940 (7) | C4—N4 | 1.146 (9) |
Zn1—N2 | 1.945 (8) | ||
S2i—Ag1—S3 | 112.9 (3) | N4—Zn1—N2 | 109.1 (3) |
S2i—Ag1—S1ii | 146.3 (3) | N4—Zn1—N1 | 119.0 (3) |
S3—Ag1—S1ii | 97.6 (2) | N2—Zn1—N1 | 105.3 (3) |
S1ii—Ag2—S2i | 168.4 (7) | N4—Zn1—N3 | 108.5 (3) |
S1ii—Ag3—S3 | 99.8 (2) | N2—Zn1—N3 | 110.3 (3) |
S1ii—Ag3—S2i | 139.8 (2) | N1—Zn1—N3 | 104.5 (3) |
S3—Ag3—S2i | 107.1 (2) | N1—C1—S1 | 176.0 (7) |
S1ii—Ag3—S3iii | 93.3 (2) | N2—C2—S2 | 177.2 (8) |
S3—Ag3—S3iii | 116.00 (19) | N3—C3—S3 | 176.7 (8) |
S2i—Ag3—S3iii | 100.9 (2) | N4—C4—S4 | 177.8 (8) |
Symmetry codes: (i) x−1/2, −y+1/2, z−1/2; (ii) x−1/2, y+1/2, z; (iii) −x, −y+1, −z. |
Subscribe to Acta Crystallographica Section C: Structural Chemistry
The full text of this article is available to subscribers to the journal.
- Information on subscribing
- Sample issue
- Purchase subscription
- Reduced-price subscriptions
- If you have already subscribed, you may need to register
Caesium silver zinc tetrathiocyanate monohydrate has been known for a century (Wells, 1902, 1922), but its anhydrous form, Cs[AgZn(SCN)4], has not been mentioned in the literature till now. Our research indicates that Cs[AgZn(SCN)4] crystallizes in two polymorphic forms, in space groups P21/n, (I), and C2/c, (II). There are a total of four different caesium silver zinc thiocyanates known in the literature, namely Cs[AgZn(SCN)4]·H2O, Cs2[AgZn(SCN)5], Cs[Ag3Zn2(SCN)8] and Cs[Ag4Zn2(SCN)9] (Wells, 1902, 1922; Güneş & Valkonen, 2002a,b). Cs, Ag and Zn all form simple thiocyanates. CsSCN crystallizes in spacegroup Pnma, AgSCN in two polymorphic forms in spacegroups C2/c and Pmnn, and Zn(NCS)2 in spacegroup P1. Also, Zn(NCS)2·2H2O is known in the literature and crystallizes in spacegroup P212121. \sch
Our interest in triple thiocyanates of silver arises from the fact that some of them, such as Cs3Sr[Ag2(SCN)7] and Cs3Ba[Ag2(SCN)7], have been found to have a noncentrosymmetric crystal structure (Bohaty & Fröhlich, 1992). A noncentrosymmetric crystal structure can possess some very interesting optical, electro-optic and electrostrictive properties, which could be utilized in, for example, telecommunications, optical computing, optical information processing, optical-disk data storage, laser remote sensing, laser-driven fusion, colour displays, medical diagnostics, and so on. The idea is based on the capability of these materials to convert IR laser radiation efficiently to visible and UV wavelengths, and especially their highly efficient second harmonic generation of blue-violet light (Wang et al., 2001).
The structure of Cs[AgZn(SCN)4] is very interesting, as it seems to crystallize in two different polymorphic forms. In (I), the structure forms a simple three-dimensional network. The Ag is bonded to four S atoms of four thiocyanate groups, which are then bonded from the other end to Zn atoms (Fig. 1). This simple bonding mode continues throughout the structure, where the Cs atoms further connect the thiocyanate groups through S and N atoms.
The Ag and Zn atoms of (I) are both tetrahedrally coordinated, the Ag surrounded by four S atoms and the Zn by four N atoms. The tetrahedron around Ag is quite strongly distorted, but the tetrahedron around Zn is nearly ideal. The Cs atom is ten-coordinated, being surrounded by five S, three C and two N atoms. The C atoms do not actually participate in bonding but Cs can, by back coordination, form a dihapto (η2) π bond to the triple C≡N bond of a thiocyanate group.
The structure of (II) is slightly more complicated, as it includes an Ag atom disordered over three sites, Ag1, Ag2, Ag3 with occupancies 0.36 (2), 0.26 (2), 0.38 (2) respectively. Only one (Ag3) of the three possible positions of the disordered Ag atom actually has clear four-coordination, which is common for an Ag atom, and the other two possible positions are clearly only three- (Ag1) and two- (Ag2) coordinated. The separations between the three disordered Ag atoms are Ag1—Ag2 0.843 (12), Ag2—Ag3 0.766 (11), Ag3—Ag1 0.775 (9) Å. However, on average, the Ag is in a four-coordinate-like environment and the structure includes a binuclear-like anion (Fig. 2), which can be compared with the binuclear [Ag2(SCN)6]4- anions in K4[Ag2(SCN)6] (Krautscheid & Gerber, 2001), where there are two [Ag(SCN)4] units sharing two common SCN- ligands.
The structure of (II) forms also a three-dimensional network, where the thiocyanate groups of the binuclear-like anion bonded from S to the delocalized Ag atom are bonded from the other end to the four-coordinated Zn atom. One of the thiocyanate groups is not bonded to Ag at all, but from N to the Zn atom and from S only to the Cs atom. The tetrahedron around Zn is very slightly distorted. The Cs atom, which connects the network in all dimensions, is a total of 13-coordinated.