Hydro­nium penta­aqua­copper(II) triperchlorate

The crystal structure of the double salt hydro­nium penta­aqua­copper(II) triperchlorate, (H₃O)[Cu(H₂O)₅](ClO₄)₃, has been determined at 180 K. In space group P3₂21, the structure contains a square-pyramidal [Cu(H₂O)₅]²⁺ moiety with its basal plane capped by one edge of a perchlorate anion, so that Cu^II exhibits [5+2] coordination. Both cations and one of the anions lie on twofold rotation axes.

Key indicators

• Single-crystal X-ray study
• T = 180 K
• Mean [sigma](Cl-O) = 0.007 Å
• H-atom completeness 77%
• R factor = 0.045
• wR factor = 0.111
• Data-to-parameter ratio = 13.6

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry

PLATON alerts of the form PLAT_7?? have been detected for an inorganic
structure. These tests are under development  for inorganics and
comments are welcomed. It is not necessary to supply a data
validation response form for these alerts at this time.


 Alert Level B:



CHEMS_01  Alert B The sum formula contains elements in the wrong order.
          H  precedes Cl
          Sequence must be C, H, then alphabetical.

PLAT_731  Alert B Bond    Calc     0.88(5), Rep   0.890(10) ......       5.00 su-Rat
                     O1   -H1A     1.555   1.555

PLAT_731  Alert B Bond    Calc     0.88(5), Rep   0.890(10) ......       5.00 su-Rat
                     O1   -H1B     1.555   1.555

PLAT_731  Alert B Bond    Calc     0.88(6), Rep   0.880(10) ......       6.00 su-Rat
                     O2   -H2A     1.555   1.555

PLAT_731  Alert B Bond    Calc     0.89(7), Rep   0.880(10) ......       7.00 su-Rat
                     O2   -H2B     1.555   1.555

PLAT_732  Alert B Angle   Calc     110(11), Rep   110.4(18) ......       6.11 su-Rat
                     H2A  -O2   -H2B     1.555   1.555   1.555

PLAT_735  Alert B D-H     Calc     0.88(5), Rep   0.890(10) ......       5.00 su-Rat
                     O1   -H1B     1.555   1.555

PLAT_735  Alert B D-H     Calc     0.88(5), Rep   0.890(10) ......       5.00 su-Rat
                     O1   -H1A     1.555   1.555

PLAT_735  Alert B D-H     Calc     0.88(6), Rep   0.880(10) ......       6.00 su-Rat
                     O2   -H2A     1.555   1.555

PLAT_735  Alert B D-H     Calc     0.89(7), Rep   0.880(10) ......       7.00 su-Rat
                     O2   -H2B     1.555   1.555


 Alert Level C:



PLAT_731  Alert C Bond    Calc   1.413(13), Rep    1.412(6) ......       2.17 su-Rat
                     CL2  -O8      1.555   5.555

PLAT_731  Alert C Bond    Calc     0.88(3), Rep   0.870(10) ......       3.00 su-Rat
                     O3   -H3A     1.555   1.555

PLAT_732  Alert C Angle   Calc      109(6), Rep   109.0(17) ......       3.53 su-Rat
                     H1A  -O1   -H1B     1.555   1.555   1.555

PLAT_735  Alert C D-H     Calc     0.88(3), Rep   0.870(10) ......       3.00 su-Rat
                     O3   -H3A     1.555   1.555

PLAT_736  Alert C H...A   Calc     2.44(7), Rep     2.44(3) ......       2.33 su-Rat
                     H2A  -O4      1.555   1.655

General Notes



FORMU_01  There is a discrepancy between the atom counts in the
          _chemical_formula_sum and the formula from the _atom_site* data.
          Atom count from _chemical_formula_sum:H13 Cl3 Cu1 O18
          Atom count from the _atom_site data:  H10 Cl3 Cu1 O18

CELLZ_01
         From the CIF: _cell_formula_units_Z    3
         From the CIF: _chemical_formula_sum  H13 Cl3 Cu O18
         TEST: Compare cell contents of formula and atom_site data

         atom    Z*formula  cif sites diff
         H         39.00     30.00    9.00
         Cl         9.00      9.00    0.00
         Cu         3.00      3.00    0.00
         O         54.00     54.00    0.00
          Difference between formula and atom_site contents detected.
          WARNING: H atoms missing from atom site list. Is this intentional?

REFLT_03
         From the CIF: _diffrn_reflns_theta_max           26.36
         From the CIF: _reflns_number_total               1610
         Count of symmetry unique reflns          940
         Completeness (_total/calc)            171.28%
         TEST3: Check Friedels for noncentro structure
         Estimate of Friedel pairs measured       670
         Fraction of Friedel pairs measured     0.713
         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.


 0 Alert Level A = Potentially serious problem

 10 Alert Level B = Potential problem

 5 Alert Level C = Please check

---

S1. Comment

The perchlorate salt of Cu^II is most commonly isolated as the green–blue hexahydrate [Cu(H₂O)₆](ClO₄)₂, containing a Jahn–Teller-distorted octahedral hexaaquacopper(II) cation (Mani & Ramaseshan, 1961; Gallucci & Gerkin, 1989). We report here the crystal structure of a double salt, (H₃O)[Cu(H₂O)₅](ClO₄)₃, incorporating pentaaquacopper(II) and a hydronium cation. In space group P3₂21, the axial Cu—OH₂ vector of the square-pyramidal [Cu(H₂O)₅²⁺] moiety is sited on a crystallographic twofold axis. The opposite face [O8ⁱ and O8ⁱⁱ; symmetry codes: (i) 1 + x, y, z; (ii): 1 + x-y, −y, 1/3 − z] of the basal plane is capped by one edge of a perchlorate anion, which is also sited on the twofold axis (Fig. 1). This gives rise to two additional Cu—O contacts of 3.305 (10) Å, so that the coordination arrangement around Cu²⁺ may be described as [5 + 2].

[5 + 2] coordination geometry is rare in Cu^II salts. The structures of other reported tetra-, penta- and hexaaquacopper(II) complexes show predominantly distorted octahedral geometry about Cu²⁺, either with six water ligands or a combination of water ligands and oxo donors from oxoanions (see, for example, Kennard et al., 1985; Manojlovic-Muir et al., 1999; Couldwell et al., 1978). Most notably, the comparable sulfate [Cu(H₂O)₅](SO₄) contains Jahn–Teller-distorted octahedral [Cu(H₂O)₄(O)₂] units, in which both axial sites are occupied by vertices of SO₄²⁻ anions that bridge between two octahedral moieties (Beevers & Lipson, 1934; Baur & Rolin, 1972; Bacon & Curry, 1962; Varghese & Maslen, 1985). The fifth water molecule in the formula unit is uncoordinated. It is notable in the title compound that the displacement parameters of O8, O2 and O3 suggest some degree of disorder (static or dynamic) towards a distorted octahedral coordination geometry about Cu²⁺. It is possible that the [5 + 2] geometry is an averaged representation of local distorted octahedral arrangements. Apparent anomalies in the octahedral coordination geometries of Cu²⁺ have been discussed recently by Persson et al. (2002).

S2. Experimental

The title compound was isolated as a by-product of an attempted complexation of Cu^II by the polyol erythritol. A mixture of 0.2705 g (2.22 mmol) erythritol was dissolved in 8 ml me thanol by warming and vigorous stirring. The solution was cooled to room temperature and 0.4114 g (1.11 mmol) Cu(ClO₄)₂·6H₂O was added. A 1 M solution of diethylamine in ethanol was diffused into this solution (vapour diffusion) and blue crystals of the title compound appeared after several months storage at room temperature.

S3. Refinement

H atoms associated with the water molecules of the [Cu(H₂O)₅]²⁺ moiety were located in difference Fourier maps and refined with O—H distances restrained to be 0.88 (1) Å and H···H distances restrained to be 1.44 (1) Å, ensuring a chemically reasonable geometry. Their displacement parameters were constrained so that U_iso(H) = 1.2U_eq(O). H atoms associated with the hydronium cation (sited on a twofold axis) were not apparent from difference Fourier maps, and were omitted from the final structure model. The hydronium atom occupies a cavity between eight potential hydrogen-bond acceptors, so that the H atoms are almost certainly disordered.

Computing details

Data collection: SMART (Bruker, 2001); cell refinement: SAINT (Bruker, 2001); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2000); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL.

Figures

Fig. 1. The molecular units in the title compound, showing displacement ellipsoids at the 50% probability level. H atoms have been omitted from the hydronium cation (O100). Symmetry codes (i), (ii) and (iii) are as given in Table 1.

Hydronium pentaaquacopper(II) triperchlorate

Crystal data

(H3O)[Cu(H2O)5](ClO4)3	Dx = 1.992 Mg m^−3
Mr = 470.99	Mo Kα radiation, λ = 0.7107 Å
Trigonal, P3221	Cell parameters from 2728 reflections
Hall symbol: P 32 2"	θ = 2.3–26.0°
a = 10.1659 (7) Å	µ = 1.99 mm^−1
c = 13.1601 (9) Å	T = 180 K
V = 1177.83 (14) Å^3	Block, blue
Z = 3	0.30 × 0.15 × 0.10 mm
F(000) = 711

Data collection

Bruker SMART 1000 CCD diffractometer	1610 independent reflections
Radiation source: fine-focus sealed tube	1348 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.050
thin–slice ω scans	θmax = 26.4°, θmin = 3.9°
Absorption correction: multi-scan (SADABS; Sheldrick, 2002)	h = −12→12
Tmin = 0.646, Tmax = 0.826	k = −11→12
7204 measured reflections	l = −16→16

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.045	Only H-atom coordinates refined
wR(F^2) = 0.111	w = 1/[σ^2(Fo^2) + (0.0515P)^2 + 2.6785P] where P = (Fo^2 + 2Fc^2)/3
S = 1.04	(Δ/σ)max < 0.001
1610 reflections	Δρmax = 0.58 e Å^−3
118 parameters	Δρmin = −0.55 e Å^−3
8 restraints	Absolute structure: Flack (1983), 671 Friedel pairs
Primary atom site location: structure-invariant direct methods	Absolute structure parameter: 0.02 (3)

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
Cu1	0.70337 (9)	0.0000	0.1667	0.0232 (2)
Cl1	0.17902 (18)	0.54783 (16)	0.14489 (10)	0.0294 (3)
Cl2	0.0840 (2)	0.0000	0.1667	0.0328 (5)
O1	0.8015 (6)	0.1870 (6)	0.0803 (4)	0.0546 (13)
H1A	0.751 (6)	0.185 (9)	0.025 (3)	0.066*
H1B	0.9000 (17)	0.238 (8)	0.067 (4)	0.066*
O2	0.7775 (13)	0.1245 (8)	0.2906 (5)	0.139 (4)
H2A	0.848 (12)	0.220 (5)	0.281 (9)	0.166*
H2B	0.740 (14)	0.112 (13)	0.353 (4)	0.166*
O3	0.4752 (7)	0.0000	0.1667	0.104 (4)
H3A	0.467 (2)	0.0813 (17)	0.173 (9)	0.125*
O4	0.0663 (5)	0.4543 (5)	0.2197 (3)	0.0448 (12)
O5	0.1916 (8)	0.6937 (6)	0.1465 (4)	0.0688 (19)
O6	0.1263 (8)	0.4798 (7)	0.0462 (4)	0.0722 (17)
O7	0.3184 (6)	0.5568 (8)	0.1644 (5)	0.0780 (19)
O8	0.0735 (12)	0.1327 (11)	0.1774 (5)	0.118 (3)
O9	0.1730 (6)	0.0179 (5)	0.0797 (3)	0.0469 (12)
O100	0.3280 (5)	0.3280 (5)	0.0000	0.0440 (16)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cu1	0.0238 (3)	0.0229 (5)	0.0227 (4)	0.0114 (3)	−0.0036 (2)	−0.0071 (4)
Cl1	0.0287 (8)	0.0273 (7)	0.0307 (6)	0.0129 (6)	0.0003 (6)	−0.0033 (5)
Cl2	0.0326 (8)	0.0484 (13)	0.0227 (10)	0.0242 (7)	0.0016 (4)	0.0032 (9)
O1	0.047 (3)	0.055 (3)	0.050 (3)	0.016 (3)	0.000 (2)	−0.001 (2)
O2	0.220 (11)	0.055 (4)	0.052 (4)	0.002 (5)	−0.001 (5)	−0.021 (3)
O3	0.036 (3)	0.083 (6)	0.208 (12)	0.042 (3)	0.051 (4)	0.101 (8)
O4	0.047 (3)	0.044 (3)	0.045 (3)	0.024 (2)	0.010 (2)	0.008 (2)
O5	0.114 (5)	0.040 (3)	0.062 (3)	0.047 (3)	0.018 (3)	0.005 (3)
O6	0.084 (4)	0.079 (4)	0.037 (2)	0.028 (3)	0.004 (3)	−0.018 (3)
O7	0.032 (3)	0.092 (5)	0.113 (5)	0.032 (4)	−0.004 (3)	−0.005 (4)
O8	0.239 (10)	0.180 (8)	0.056 (3)	0.196 (8)	0.022 (5)	0.016 (5)
O9	0.064 (3)	0.039 (2)	0.036 (2)	0.024 (2)	0.017 (2)	0.0052 (19)
O100	0.042 (3)	0.042 (3)	0.043 (3)	0.018 (3)	−0.0010 (13)	0.0010 (13)

Geometric parameters (Å, º)

Cu1—O2	1.969 (6)	Cl1—O4	1.449 (5)
Cu1—O2^i	1.969 (6)	Cl2—O8^i	1.412 (6)
Cu1—O1^i	2.001 (5)	Cl2—O8	1.412 (6)
Cu1—O1	2.001 (5)	Cl2—O9^i	1.413 (4)
Cu1—O3	2.320 (7)	Cl2—O9	1.413 (4)
Cu1—O8^ii	3.305 (10)	O1—H1A	0.89 (1)
Cu1—O8^iii	3.305 (10)	O1—H1B	0.89 (1)
Cl1—O7	1.398 (5)	O2—H2A	0.88 (1)
Cl1—O5	1.423 (5)	O2—H2B	0.88 (1)
Cl1—O6	1.443 (5)	O3—H3A	0.87 (1)
O2—Cu1—O2^i	172.9 (8)	O8^ii—Cu1—O8^iii	41.7 (3)
O2—Cu1—O1^i	89.2 (3)	O7—Cl1—O5	111.7 (4)
O2^i—Cu1—O1^i	90.7 (3)	O7—Cl1—O6	108.5 (4)
O2—Cu1—O1	90.7 (3)	O5—Cl1—O6	109.3 (4)
O2^i—Cu1—O1	89.2 (3)	O7—Cl1—O4	111.2 (3)
O1^i—Cu1—O1	177.3 (3)	O5—Cl1—O4	107.7 (3)
O2—Cu1—O3	93.5 (4)	O6—Cl1—O4	108.4 (3)
O2^i—Cu1—O3	93.5 (4)	O8^i—Cl2—O8	112.8 (9)
O1^i—Cu1—O3	91.34 (17)	O8^i—Cl2—O9^i	107.9 (3)
O1—Cu1—O3	91.34 (17)	O8—Cl2—O9^i	109.3 (4)
O2—Cu1—O8^ii	73.2 (4)	O8^i—Cl2—O9	109.3 (4)
O2^i—Cu1—O8^ii	100.0 (4)	O8—Cl2—O9	107.9 (3)
O1^i—Cu1—O8^ii	104.2 (2)	O9^i—Cl2—O9	109.7 (4)
O1—Cu1—O8^ii	73.2 (2)	Cu1—O1—H1A	116 (5)
O3—Cu1—O8^ii	159.15 (13)	Cu1—O1—H1B	123 (5)
O2—Cu1—O8^iii	100.0 (4)	H1A—O1—H1B	109.0 (17)
O2^i—Cu1—O8^iii	73.2 (4)	Cu1—O2—H2A	116 (8)
O1^i—Cu1—O8^iii	73.2 (2)	Cu1—O2—H2B	132 (8)
O1—Cu1—O8^iii	104.2 (2)	H2A—O2—H2B	110.4 (18)
O3—Cu1—O8^iii	159.15 (13)	Cu1—O3—H3A	124.5 (11)

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

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1B···O6^ii	0.89 (1)	2.40 (5)	3.184 (8)	148 (7)
O1—H1A···O5^iv	0.89 (1)	2.34 (3)	3.188 (7)	161 (6)
O2—H2A···O4^ii	0.88 (1)	2.44 (3)	3.299 (10)	165 (11)
O2—H2B···O7^v	0.88 (1)	2.58 (7)	3.343 (11)	145 (10)
O3—H3A···O5^vi	0.87 (1)	2.16 (1)	3.017 (7)	168 (2)

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