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quantum crystallography
Bonding properties in the crystal of 4,5-dichloro-l,2,3-dithiazolium chloride (Appel's salt) were studied using a combination of single-crystal high-resolution X-ray diffraction data and the orbital-free quantum crystallography approach. A QTAIM-based topological model shows the proximity of S—C and S—N bonds to the sesquialteral type and establishes the low S—S bond order in the l,2,3-dithiazolium heterocycle. It is found that the electrostatic potential carries the traces of a common positive area on the junction of interatomic zero-flux surfaces of S1 and S2 atomic basins; meanwhile the exchange energy density per particle shows perfectly here two separate minima through which the two bond paths run. Thus, the pair intermolecular interactions Cl−
S1 and Cl−S2 formed by the common chloride anion placed near the center of the S—S bond are categorized as chalcogen bonds.
S1 and Cl−S2 formed by the common chloride anion placed near the center of the S—S bond are categorized as chalcogen bonds.Keywords: Appel's salt; charge density; chalcogen bond; halogen bond; exchange energy density per particle; quantum crystallography.
Supporting information
 | Crystallographic Information File (CIF) https://doi.org/10.1107/S2052520621005928/px5038sup1.cif |
 | Structure factor file (CIF format) https://doi.org/10.1107/S2052520621005928/px5038Isup2.hkl |
CCDC reference: 2088696
Computing details top
Cell refinement: SAINT V8.38A (Bruker AXS Inc., 2013) for (I). Data reduction: SAINT V8.38A (Bruker AXS Inc., 2013) for (I). Program(s) used to solve structure: SHELXT-2018/3 (Sheldrick, 2018) for (I). Program(s) used to refine structure: SHELXL2013/8 (Sheldrick, 2018) for (I); Volkov et al., (2006) for Appel_mult. Molecular graphics: Bruker SHELXTL (Bruker AXS Inc., 2013) for (I); Volkov et al., (2006) for Appel_mult. Software used to prepare material for publication: Volkov et al., (2006) for Appel_mult.
(I) top
Crystal data top
| C2Cl2NS2·Cl | Dx = 2.088 Mg m−3 |
| Mr = 208.50 | Mo Kα radiation, λ = 0.71073 Å |
| Orthorhombic, P212121 | Cell parameters from 9877 reflections |
| a = 5.90947 (10) Å | θ = 2.7–39.7° |
| b = 10.22455 (16) Å | µ = 1.89 mm−1 |
| c = 10.97838 (18) Å | T = 100 K |
| V = 663.33 (2) Å3 | Block-like, dark brown |
| Z = 4 | 0.58 × 0.12 × 0.11 mm |
| F(000) = 408 |
Data collection top
| Bruker Quest D8 diffractometer with Photon III detector | 12387 reflections with I > 2σ(I) |
| ω–scan | Rint = 0.024 |
| Absorption correction: multi-scan SADABS-2016/2 - Bruker AXS area detector scaling and absorption correction | θmax = 71.6°, θmin = 2.7° |
| Tmin = 0.566, Tmax = 0.724 | h = −14→15 |
| 102642 measured reflections | k = −26→27 |
| 12761 independent reflections | l = −29→29 |
Refinement top
| Refinement on F2 | 0 restraints |
| Least-squares matrix: full | w = 1/[σ2(Fo2) + (0.0193P)2 + 0.0166P] where P = (Fo2 + 2Fc2)/3 |
| R[F2 > 2σ(F2)] = 0.014 | (Δ/σ)max = 0.003 |
| wR(F2) = 0.040 | Δρmax = 0.49 e Å−3 |
| S = 1.07 | Δρmin = −0.55 e Å−3 |
| 12761 reflections | Absolute structure: Flack x determined using 5383 quotients [(I+)-(I-)]/[(I+)+(I-)] (Parsons, Flack and Wagner, Acta Cryst. B69 (2013) 249-259). |
| 73 parameters | Absolute structure parameter: 0.273 (7) |
Special details top
Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes. |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
| x | y | z | Uiso*/Ueq | ||
| Cl1 | 0.28475 (3) | 0.74344 (2) | 0.60078 (2) | 0.01886 (2) | |
| Cl2 | −0.03886 (2) | 0.53741 (2) | 0.75136 (2) | 0.01531 (1) | |
| Cl3 | 0.48426 (2) | 0.08785 (2) | 0.59885 (2) | 0.01301 (1) | |
| S1 | 0.27725 (2) | 0.33636 (2) | 0.67299 (2) | 0.01203 (1) | |
| S2 | 0.54906 (2) | 0.37393 (2) | 0.56445 (2) | 0.01248 (1) | |
| N1 | 0.51415 (6) | 0.53003 (3) | 0.55287 (3) | 0.01376 (3) | |
| C1 | 0.33891 (6) | 0.57994 (3) | 0.60914 (3) | 0.01276 (4) | |
| C2 | 0.19775 (6) | 0.49364 (3) | 0.67624 (3) | 0.01212 (3) |
Atomic displacement parameters (Å2) top
| U11 | U22 | U33 | U12 | U13 | U23 | |
| Cl1 | 0.02390 (4) | 0.01003 (2) | 0.02265 (4) | 0.00335 (2) | 0.00101 (4) | 0.00118 (2) |
| Cl2 | 0.01380 (3) | 0.01544 (3) | 0.01668 (3) | 0.00184 (2) | 0.00185 (2) | −0.00338 (2) |
| Cl3 | 0.01313 (2) | 0.01159 (2) | 0.01431 (2) | 0.00126 (2) | 0.00119 (2) | 0.00060 (2) |
| S1 | 0.01314 (3) | 0.00975 (2) | 0.01320 (2) | −0.00035 (2) | 0.00160 (2) | −0.00013 (2) |
| S2 | 0.01325 (3) | 0.00998 (2) | 0.01422 (3) | 0.00051 (2) | 0.00215 (2) | −0.00003 (2) |
| N1 | 0.01559 (9) | 0.01034 (6) | 0.01534 (8) | −0.00005 (6) | 0.00207 (7) | 0.00064 (6) |
| C1 | 0.01502 (9) | 0.00973 (7) | 0.01352 (9) | 0.00078 (6) | −0.00014 (7) | −0.00002 (6) |
| C2 | 0.01295 (8) | 0.01117 (7) | 0.01224 (8) | 0.00074 (6) | 0.00017 (7) | −0.00139 (6) |
Geometric parameters (Å, º) top
| Cl1—C1 | 1.7045 (3) | S2—N1 | 1.6143 (3) |
| Cl2—C2 | 1.6838 (4) | N1—C1 | 1.3094 (5) |
| S1—C2 | 1.6757 (3) | C1—C2 | 1.4203 (5) |
| S1—S2 | 2.0366 (1) | ||
| C2—S1—S2 | 93.014 (13) | C2—C1—Cl1 | 121.80 (3) |
| N1—S2—S1 | 97.570 (13) | C1—C2—S1 | 114.87 (3) |
| C1—N1—S2 | 116.70 (3) | C1—C2—Cl2 | 125.21 (3) |
| N1—C1—C2 | 117.84 (3) | S1—C2—Cl2 | 119.89 (2) |
| N1—C1—Cl1 | 120.36 (3) |
(Appel_mult) top
Refinement top
| Refinement on F2 | 9426 reflections |
| Least-squares matrix: full | 414 parameters |
| R[F2 > 2σ(F2)] = 0.009 | 0 restraints |
| wR(F2) = 0.011 | w2 = q/[s2(Fo2) + (0.01 P)2 + 0.00 P + 0.00 + 0.00 sin(th)]
where P = (0.3333 Fo2 + 0.6667 Fc2) q = 1.0 |
| S = 1.40 | (Δ/σ)max < 0.001 |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
| x | y | z | Uiso*/Ueq | ||
| Cl(1) | 0.28457 (7) | 0.74324 (2) | 0.60055 (4) | 0.019 | |
| Cl(2) | −0.03844 (5) | 0.53756 (3) | 0.75118 (2) | 0.016 | |
| Cl(3) | 0.48423 (4) | 0.08786 (2) | 0.59881 (2) | 0.013 | |
| S(1) | 0.27720 (4) | 0.33636 (2) | 0.67291 (2) | 0.012 | |
| S(2) | 0.54893 (4) | 0.37393 (2) | 0.56454 (2) | 0.013 | |
| N(1) | 0.51412 (3) | 0.529971 (16) | 0.552909 (18) | 0.014 | |
| C(1) | 0.33882 (4) | 0.580022 (17) | 0.609172 (19) | 0.013 | |
| C(2) | 0.19767 (3) | 0.493656 (18) | 0.676274 (18) | 0.012 |
Atomic displacement parameters (Å2) top
| U11 | U22 | U33 | U12 | U13 | U23 | |
| Cl(1) | 0.02510 (11) | 0.01005 (6) | 0.02313 (10) | 0.00356 (6) | 0.00106 (9) | 0.00108 (6) |
| Cl(2) | 0.01443 (7) | 0.01575 (7) | 0.01701 (7) | 0.00192 (5) | 0.00180 (6) | −0.00347 (6) |
| Cl(3) | 0.01360 (6) | 0.01152 (5) | 0.01460 (6) | 0.00132 (4) | 0.00135 (5) | 0.00060 (5) |
| S(1) | 0.01368 (7) | 0.00971 (5) | 0.01347 (6) | −0.00036 (5) | 0.00160 (5) | −0.00017 (5) |
| S(2) | 0.01384 (7) | 0.00994 (5) | 0.01443 (6) | 0.00054 (5) | 0.00221 (5) | −0.00009 (5) |
| N(1) | 0.01572 (5) | 0.01029 (4) | 0.01568 (5) | −0.00001 (3) | 0.00242 (4) | 0.00073 (3) |
| C(1) | 0.01503 (5) | 0.00968 (4) | 0.01378 (5) | 0.00083 (3) | 0.00000 (4) | −0.00006 (4) |
| C(2) | 0.01309 (5) | 0.01107 (4) | 0.01247 (4) | 0.00079 (3) | 0.00035 (4) | −0.00131 (3) |
