Crystal structures of hydrates of simple inorganic salts. II. Water-rich calcium bromide and iodide hydrates: CaBr₂·9H₂O, CaI₂·8H₂O, CaI₂·7H₂O and CaI₂·6.5H₂O

Single crystals of calcium bromide enneahydrate, CaBr₂·9H₂O, calcium iodide octa­hydrate, CaI₂·8H₂O, calcium iodide hepta­hydrate, CaI₂·7H₂O, and calcium iodide 6.5-hydrate, CaI₂·6.5H₂O, were grown from their aqueous solutions at and below room temperature according to the solid-liquid phase diagram. The crystal structure of CaI₂·6.5H₂O was redetermined. All four structures are built up from distorted Ca(H₂O)₈ anti­prisms. The anti­prisms of the iodide hydrate structures are connected either via trigonal-plane-sharing or edge-sharing, forming dimeric units. The anti­prisms in calcium bromide enneahydrate are monomeric.

S1. Introduction

The ongoing discussion about the possibilities of the existence of aqueous salt solutions and hydrates on the surface of our neighbour planet Mars at temperatures down to 193 K (Renno et al., 2009) made clear that the present knowledge on salt–water systems at very low temperatures is insufficient for profound explanations and predictions. Examples of water–salt systems with deep eutectic temperatures have been published (Brass, 1980; Möhlmann & Thomsen, 2011); however, often the water content of the corresponding solid–liquid equilibrium is uncertain or not known, because the water-rich hydrates crystallizing below 273 K are difficult to separate completely from the viscous mother liquor. For many simple water–salt systems, the solid–liquid equilibria are not known down to the eutectic temperature. We began a program for the systematic study of such equilibria taking care particularly to study the composition and structure of water-rich hydrates. Apart from application aspects in planetary science, in the fields of cold-climate and tropospheric research, the structures of water-rich hydrates can give hints for tendencies to nucleation and structure formation in concentrated salt solutions.

In a first communication, we reported crystal structures of magnesium halide hydrates (MgCl₂.8H₂O, MgCl₂.12H₂O, MgBr₂.6H₂O, MgBr₂.9H₂O, MgI₂.8H₂O and MgI₂.9H₂O; Hennings et al., 2013) and discussed the stepwise build-up of a second hydration shell around the cation, when the hydrates contain more than six waters. In this second part, we report the crystal structures of calcium halide hydrates, which are formed under equilibrium conditions from aqueous solutions at low temperatures. Since the CaCl₂–H₂O system has been investigated several times, down to the eutectic temperature of 218 K, we did not reinvestigate this system, and accept the fact that the hexahydrate represents the stable solid phase at low temperatures (Roozeboom, 1889). For the bromide and iodide systems, the reported solid–liquid phase diagrams at low temperatures (Kremers, 1858; Jones & Getman, 1904; Milikan, 1917; Rakowsky & Garrett, 1954) were incomplete. Therefore a reinvestigation seemed to be worthwhile. At room temperature, Leclaire & Borel (1977) found for the bromide a hexahydrate isostructural with the corresponding chloride. However, in the case of iodide, the crystal structure analysis (Thiele & Putzas, 1984) revealed a CaI₂.6.5H₂O. Furthermore, these authors pointed out that attempts to prepare a hexahydrate of the iodide were not successful. At lower temperatures, we isolated the higher hydrates CaBr₂.9H₂O, CaI₂.7H₂O and CaI₂.8H₂O, and these structures shall be discussed below. The structure of CaI₂.6.5H₂O was re-investigated to include the H-atom positions.

S2. Experimental

S2.1. Synthesis and crystallization

CaI₂.6.5H₂O was crystallized from an aqueous solution of 69.7 wt% CaI₂ at 298 K for 1 d, CaI₂.7H₂O from a solution of 61.3 wt% CaI₂ at 233 K for 3 d, and CaI₂.8H₂O from an aqueous solution of 53.7 wt% CaI₂ at 187 K for 1 d. For the preparation of these aqueous solutions, calcium iodide tetra­hydrate (CaI₂.4H₂O, Acros Organics, 99%) was used. CaBr₂.9H₂O was crystallized from an aqueous solution of 45.7 wt% CaBr₂ (CaBr₂.H₂O, Merck, pA) at 228 K for 20 d. The Ca²⁺ content of all solutions was analyzed by complexometric titration with ethyl­enedi­amine­tetra­acetic acid (EDTA). All crystals showed no changes during an observations period of four weeks as saturated solutions. Crystal shape and size is given in Table 1 for all determined structures.

The samples were stored in a freezer or a cryostat at low temperatures. CaI₂.6.5H₂O crystallized at room temperature. The crystals were separated and embedded in perflourinated ether (Galden 1438OB, Solvay Solexis) for X-ray analysis.

S2.2. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 1. All H atoms in each structure were placed in the positions indicated by difference Fourier maps and refined isotropically. Distance restraints were applied for all water molecule geometries for all water molecules, with O—H and H···H distance restraints of 0.82 (1) and 1.32 (1) Å, respectively.

S3. Results and discussion

S3.1. Calcium bromide enneahydrate CaBr\\\\\\\~2\\\\\\\~.9H\\\\\\\~2\\\\\\\Õ

Calcium bromide enneahydrate represents the water-richest calcium salt hydrate prepared to date. Although nine water molecules would be available for Ca²⁺, the primary coordination sphere is formed only by eight water molecules, as can be seen in Fig. 1. The excess water is accommodated between the isolated cation polyhedra. A search in the ICSD (Inorganic Crystal Structure Database; 2014; https://icsd.fiz-karlsruhe.de/icsd/) for water-rich calcium salts also confirmed that a hydration number of eight is never exceeded with water, even in the presence of large anions [CaO₂.8H₂O (Shineman & King, 1951), CaB₁₂H₁₂.8H₂O (Tiritiris & Schleid, 2001) and Ca(I₅)₂.7H₂O (Thomas & Moore, 1981)]. The hydration polyhedron takes the form of a quadratic anti­prism (Fig. 1b). Along the b axis, nearest edges of the prisms are connected through 2.18 Å hydrogen bonds, forming zigzag chains (Table 2 and Fig. 2a; chains are highlighted). Perpendicular to the bc plane, the lattice water atom O9 connects the chains within the ab plane, as highlighted in Fig. 3(a). The hydrogen-bond network of the calcium aqua complexes is completed through the bromide ions located between the layers of anti­prisms. Every bromide ion forms four (Br1) or five (Br2) Br···H bonds when considering distances between 2.4 and 2.6 Å (Table 2 and Fig. 2b).

S3.2. Calcium iodide hydrates CaI\\\\\\\~2\\\\\\\~.8H\\\\\\\~2\\\\\\\Õ, CaI\\\\\\\~.7H\\\\\\\~2\\\\\\\Õ and CaI\\\\\\\~2\\\\\\\~.6.5H\\\\\\\~2\\\\\\\Õ

The unit-cell parameters of the iodide and bromide hydrates are included in Table 1. Our redetermination of the 6.5-hydrate confirms the data of Thiele & Putzas (1984) with respect to the space group. The unit-cell parameters and atomic coordinates of Ca, I and O of Thiele & Putzas (1984) deviate from our results since the authors stated an `approximate determination by film methods', and used a different measurement temperature. We included and refined the H atoms in the final model. In all three hydrates, the Ca²⁺ ion is coordinated by eight molecules of water (Fig. 4). The structure of the heptahydrate contains two crystallographically distinct Ca²⁺ positions, while the other hydrates contain only one. The geometry of the hydration spheres of calcium are illustrated in Fig. 5. In each hydrate, the polyhedron formed by water molecules around Ca²⁺ can be described to a good approximation as a quadratic anti­prism. It is inter­esting to note that these prisms are dimers in all three hydrates. In case of the 6.5-hydrate, the anti­prisms share a trigonal face, whereas the anti­prisms of the other two hydrates share a common edge. Although the o­cta­hydrate contains enough water for the formation of isolated o­cta­aqua complexes, the dimer structure is preferred by the calcium ions with the consequence of an extra lattice water outside the primary hydration sphere of Ca²⁺. The structural reason for the dimerization is not clear, since in other examples of o­cta­hydrates with large anions, noted in the Introduction (section 1), the hydration spheres of Ca²⁺ are monomeric. A more detailed inspection of the structural features reveals that the mean Ca—O distances and its range in the hydration complexes does not vary systematically for the different hydrates including the bromide (Table 2). The mean distance remains remarkably constant, independent on the water content. It seems that the quadratic anti­prism represents a quite stable hydration geometry for calcium, even if the squares are not exact planes, since the kinks ruffling is not pronounced enough for a transition to a tridodecahedron. Particularly, for the 6.5-hydrate, one would expect some structural similarity to the well-known hexahydrate structures of the bromide and chloride of calcium (Leclaire & Borel, 1977). Indeed, one could imagine a depolymerization of the trigonal tricapped [Ca(H₂O)6/2(H₂O)3] columns by the additional water in a transition from the 6.0- to the 6.5-hydrate, as shown in Fig. 6.

Whereas the structure of CaI.6.5H₂O still resembles the original highly symmetric structure of CaBr₂.6H₂O (at least in the view direction shown in in Fig. 6), this similarity is lost in the higher hydrates. For the higher hydrates, a tendency for separation of the large anions and the hydrated cations in distinguished layers can be recognized (Fig. 7). Although, hydrogen-bond distances between I and H atoms are present, they do not seem to control the structure, as was pointed out already by Thiele & Putzas (1984). Apparently, efficient packing is more important. This can be seen also in the orientation of the lattice water molecules in CaI₂.8H₂O and CaBr₂.9H₂O, as shown in Fig. 3. The water is oriented so as to optimize the hydrogen bonding to the calcium aqua complexes, the remaining hydrogen bond to the bromide or iodide is merely an effect of packing.

Summarizing the structural findings on water-rich calcium halide hydrates, it is surprising that in CaCl₂.6H₂O, with only six water of hydration, the Ca²⁺ ion maintains a primary hydration sphere including nine water molecules sharing six along trigonal–prismatic columns (Agron & Busing, 1986; Leclaire & Borel, 1977). In all other halides that are richer in water, the coordination number of Ca²⁺ is eight, even if there is excess water available, as in the nonahydrates. Probably the peculiar geometrical coincidence of radii of about 1.3 Å for Ca²⁺ (Shannon, 1976) and water on one side and 1.7 Å for Cl^- on the other side enables this extensive sharing of coordinated water accompanied by an effective hydrogen-bonding network in CaCl₂.6H₂O. The particular stability of this structure and the associated radii could also explain why even at the eutectic temperature of 218 K no higher hydrate could be crystallized for CaCl₂. In case of the bromide, a hexahydrate isostructural with the chloride is crystallized; however, the lattice energy is obviously not as favourable as for the chloride. Thus, at temperatures below 252 K, a nonahydrate crystallizes from bromide solutions (Hennings & Voigt, 2014).

Related literature

For related literature, see: Agron & Busing (1986); Brass (1980); Hennings & Voigt (2014); Hennings et al. (2013); Jones & Getman (1904); Kremers (1858); Leclaire & Borel (1977); Möhlmann & Thomsen (2011); Milikan (1917); Rakowsky & Garrett (1954); Renno (2009); Roozeboom (1889); Shannon (1976); Shineman & King (1951); Thiele & Putzas (1984); Thomas & Moore (1981); Tiritiris & Schleid (2001).

Computing details

For all compounds, data collection: X-AREA (Stoe & Cie, 2009); cell refinement: X-AREA (Stoe & Cie, 2009); data reduction: X-RED (Stoe & Cie, 2009); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL2012 (Sheldrick, 2008); molecular graphics: SHELXL2012 (Sheldrick, 2008); software used to prepare material for publication: SHELXL2012 (Sheldrick, 2008).

Figures

	Fig. 1. (a) The asymmetric unit and (b) the quadratic antiprism as the coordination polyhedron in CaBr2.9H2O. Displacement ellipsoids are drawn at the 50% probability level.
	Fig. 2. (a) The formation of chains along b (Br atoms not shown for clarity). (b) The location and coordination of Br atoms by hydrogen bonds in the bc plane. Dashed lines indicate hydrogen bonds.
	Fig. 3. The asymmetric unit of (a) CaI2.6.5H2O [symmetry code: (i) -x+1, y, -z+1/2], (b) CaI2.7H2O and (c) CaI2.8H2O. Displacement ellipsoids are drawn at the 50% probability level.
	Fig. 4. The arrangement of I atoms in a distance up to 3.05 Å from water H atoms around dimers in (a) CaI2.6.5H2O, (b) CaI2.7H2O and (c) CaI2.8H2O.
	Fig. 5. Structural similarities between CaBr2.6H2O (Leclaire & Borel, 1977) and CaI2.6.5H2O.
	Fig. 6. The formation of layers in (a) CaI2.7H2O and (b) CaI2.8H2O.
	Fig. 7. The hydrogen-bonding scheme for free water molecules in (a) CaBr2.H2O and, in comparison, (b) for CaI2.8H2O. Dashed lines indicate hydrogen bonds.

(CaBr2_9H2O_100K) Calcium bromide nonahydrate

Crystal data

CaBr2·9H2O	F(000) = 720
Mr = 362.02	Dx = 1.956 Mg m^−3
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71073 Å
a = 7.8354 (8) Å	Cell parameters from 2310 reflections
b = 8.7538 (5) Å	θ = 2.3–29.6°
c = 18.2615 (18) Å	µ = 7.03 mm^−1
β = 101.041 (8)°	T = 100 K
V = 1229.36 (19) Å^3	Prismatic, colourless
Z = 4	0.6 × 0.34 × 0.27 mm

Data collection

Stoe IPDS 2T diffractometer	3495 independent reflections
Radiation source: sealed X-ray tube, 12 x 0.4 mm long-fine focus	2968 reflections with I > 2σ(I)
Detector resolution: 6.67 pixels mm^-1	Rint = 0.100
rotation method scans	θmax = 27.3°, θmin = 2.6°
Absorption correction: integration (Coppens, 1970)	h = −10→10
Tmin = 0.081, Tmax = 0.297	k = −10→12
3495 measured reflections	l = −25→25

Refinement

Refinement on F^2	Hydrogen site location: difference Fourier map
Least-squares matrix: full	Only H-atom coordinates refined
R[F^2 > 2σ(F^2)] = 0.036	w = 1/[σ^2(Fo^2) + (0.0365P)^2 + 1.2235P] where P = (Fo^2 + 2Fc^2)/3
wR(F^2) = 0.084	(Δ/σ)max = 0.001
S = 1.10	Δρmax = 1.33 e Å^−3
2826 reflections	Δρmin = −1.45 e Å^−3
166 parameters	Extinction correction: SHELXL2012 (Sheldrick, 2008), Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
25 restraints	Extinction coefficient: 0.0023 (5)

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
Br1	0.52307 (4)	0.71505 (3)	0.22957 (2)	0.01504 (11)
Br2	0.00258 (4)	0.19104 (3)	0.87402 (2)	0.01546 (11)
Ca1	0.41441 (7)	0.23986 (6)	0.10287 (3)	0.00879 (14)
O7	0.1079 (3)	0.2300 (2)	0.05865 (13)	0.0147 (4)
H7A	0.039 (4)	0.292 (3)	0.069 (2)	0.018*
H7B	0.069 (5)	0.202 (3)	0.0161 (9)	0.005 (8)*
O8	0.3610 (3)	0.5185 (2)	0.06304 (12)	0.0138 (4)
H8A	0.285 (3)	0.522 (4)	0.0251 (10)	0.017*
H8B	0.320 (4)	0.561 (4)	0.0959 (12)	0.017*
O6	0.4201 (3)	0.2468 (2)	−0.03275 (12)	0.0126 (4)
H6A	0.324 (3)	0.239 (4)	−0.0596 (18)	0.015*
H6B	0.472 (5)	0.316 (3)	−0.050 (2)	0.015*
O2	0.6532 (3)	0.3952 (2)	0.17140 (12)	0.0140 (4)
H2A	0.723 (4)	0.347 (3)	0.2019 (15)	0.017*
H2B	0.627 (5)	0.472 (3)	0.1919 (18)	0.036 (13)*
O1	0.2750 (3)	0.3823 (2)	0.19272 (12)	0.0149 (4)
H1A	0.201 (3)	0.336 (4)	0.2104 (17)	0.018*
H1B	0.343 (4)	0.419 (4)	0.2280 (13)	0.018*
O4	0.6901 (3)	0.1232 (3)	0.08975 (12)	0.0170 (4)
H4B	0.708 (5)	0.083 (4)	0.0516 (13)	0.020*
H4A	0.778 (3)	0.102 (4)	0.1200 (17)	0.020*
O5	0.3302 (3)	−0.0246 (2)	0.06151 (12)	0.0140 (4)
H5A	0.252 (3)	−0.060 (4)	0.081 (2)	0.017*
H5B	0.414 (3)	−0.083 (3)	0.073 (2)	0.017*
O3	0.4753 (3)	0.0966 (2)	0.21596 (12)	0.0198 (5)
H3A	0.487 (5)	0.0038 (12)	0.2188 (18)	0.024*
H3B	0.474 (6)	0.129 (3)	0.2579 (10)	0.024*
O9	0.1293 (3)	0.5406 (2)	0.92976 (12)	0.0154 (4)
H9A	0.087 (4)	0.457 (2)	0.9169 (18)	0.018*
H9B	0.187 (4)	0.566 (4)	0.8988 (16)	0.018*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Br1	0.01305 (17)	0.01404 (15)	0.01665 (19)	0.00043 (10)	−0.00059 (12)	−0.00486 (10)
Br2	0.01464 (17)	0.01936 (16)	0.00992 (18)	−0.00484 (10)	−0.00385 (12)	0.00137 (10)
Ca1	0.0083 (3)	0.0107 (2)	0.0061 (3)	−0.00029 (19)	−0.0018 (2)	−0.00007 (19)
O7	0.0113 (10)	0.0188 (10)	0.0125 (11)	0.0016 (8)	−0.0018 (8)	−0.0030 (8)
O8	0.0145 (10)	0.0163 (9)	0.0092 (9)	−0.0003 (8)	−0.0011 (8)	−0.0002 (8)
O6	0.0112 (10)	0.0162 (9)	0.0085 (10)	−0.0007 (8)	−0.0029 (8)	0.0022 (8)
O2	0.0116 (9)	0.0130 (9)	0.0149 (10)	0.0036 (7)	−0.0037 (8)	−0.0026 (8)
O1	0.0122 (10)	0.0210 (10)	0.0111 (10)	−0.0022 (8)	0.0014 (8)	−0.0031 (8)
O4	0.0104 (10)	0.0249 (11)	0.0135 (11)	0.0061 (8)	−0.0028 (8)	−0.0029 (9)
O5	0.0117 (10)	0.0136 (9)	0.0164 (10)	0.0012 (8)	0.0018 (8)	−0.0013 (8)
O3	0.0346 (13)	0.0135 (9)	0.0104 (10)	0.0017 (9)	0.0019 (9)	0.0004 (8)
O9	0.0145 (10)	0.0153 (10)	0.0151 (11)	0.0003 (8)	−0.0001 (8)	0.0013 (8)

Geometric parameters (Å, º)

Ca1—O1	2.475 (2)	Ca1—O5	2.485 (2)
Ca1—O2	2.453 (2)	Ca1—O6	2.486 (2)
Ca1—O3	2.385 (2)	Ca1—O7	2.384 (2)
Ca1—O4	2.442 (2)	Ca1—O8	2.557 (2)
O7—Ca1—O3	107.20 (9)	O1—Ca1—O5	123.05 (7)
O7—Ca1—O4	143.51 (8)	O7—Ca1—O6	82.68 (8)
O3—Ca1—O4	80.28 (8)	O3—Ca1—O6	146.79 (7)
O7—Ca1—O2	144.41 (7)	O4—Ca1—O6	74.19 (7)
O3—Ca1—O2	80.97 (8)	O2—Ca1—O6	109.70 (7)
O4—Ca1—O2	71.31 (7)	O1—Ca1—O6	137.94 (7)
O7—Ca1—O1	72.48 (7)	O5—Ca1—O6	76.97 (7)
O3—Ca1—O1	74.41 (8)	O7—Ca1—O8	80.73 (7)
O4—Ca1—O1	141.88 (8)	O3—Ca1—O8	137.96 (7)
O2—Ca1—O1	76.88 (7)	O4—Ca1—O8	118.08 (8)
O7—Ca1—O5	70.82 (7)	O2—Ca1—O8	71.56 (7)
O3—Ca1—O5	76.75 (7)	O1—Ca1—O8	68.84 (7)
O4—Ca1—O5	76.64 (7)	O5—Ca1—O8	141.52 (7)
O2—Ca1—O5	143.48 (7)	O6—Ca1—O8	74.12 (7)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O9—H9B···O2^i	0.82 (1)	1.98 (1)	2.800 (3)	173 (4)
O9—H9A···Br2	0.82 (1)	2.50 (1)	3.316 (2)	172 (3)
O3—H3B···Br2^ii	0.82 (1)	2.62 (1)	3.405 (2)	162 (3)
O3—H3A···Br1^iii	0.82 (1)	2.55 (1)	3.365 (2)	179 (3)
O5—H5B···O6^iv	0.82 (1)	2.16 (2)	2.878 (3)	146 (3)
O5—H5A···Br2^v	0.82 (1)	2.57 (1)	3.388 (2)	173 (4)
O4—H4B···O5^iv	0.82 (1)	2.09 (2)	2.869 (3)	159 (4)
O1—H1B···Br2^ii	0.82 (1)	2.88 (3)	3.506 (2)	134 (3)
O1—H1A···Br1^vi	0.82 (1)	2.48 (1)	3.298 (2)	176 (3)
O2—H2B···Br1	0.82 (1)	2.42 (1)	3.228 (2)	169 (3)
O2—H2A···Br1^vii	0.82 (1)	2.43 (1)	3.230 (2)	166 (4)
O6—H6B···O8^viii	0.82 (1)	2.00 (2)	2.798 (3)	164 (4)
O6—H6A···Br2^ix	0.82 (1)	2.61 (1)	3.422 (2)	170 (4)
O8—H8B···O1	0.82 (1)	2.44 (3)	2.845 (3)	112 (3)
O8—H8A···O9^ix	0.82 (1)	1.93 (1)	2.750 (3)	173 (4)
O7—H7B···Br2^ix	0.82 (1)	2.55 (2)	3.332 (2)	161 (3)
O7—H7A···O9^x	0.82 (1)	1.97 (1)	2.772 (3)	167 (4)

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

(CaI2_8H2O_100K) Calcium iodide octahydrate

Crystal data

CaI2·8H2O	Z = 2
Mr = 438.01	F(000) = 412
Triclinic, P1	Dx = 2.230 Mg m^−3
a = 7.4521 (14) Å	Mo Kα radiation, λ = 0.71073 Å
b = 8.6127 (19) Å	Cell parameters from 13177 reflections
c = 10.725 (2) Å	θ = 2.3–59.5°
α = 86.048 (17)°	µ = 5.22 mm^−1
β = 84.184 (16)°	T = 100 K
γ = 72.427 (16)°	Plate, colourless
V = 652.3 (2) Å^3	0.32 × 0.22 × 0.12 mm

Data collection

Stoe IPDS 2T diffractometer	2994 independent reflections
Radiation source: 'sealed X-ray tube, 12 x 0.4 mm long-fine focus'	2846 reflections with I > 2σ(I)
Detector resolution: 6.67 pixels mm^-1	Rint = 0.069
rotation method scans	θmax = 27.5°, θmin = 2.9°
Absorption correction: integration (Coppens, 1970)	h = −9→9
Tmin = 0.262, Tmax = 0.544	k = −11→11
7283 measured reflections	l = −13→13

Refinement

Refinement on F^2	22 restraints
Least-squares matrix: full	Hydrogen site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.035	All H-atom parameters refined
wR(F^2) = 0.096	w = 1/[σ^2(Fo^2) + (0.0545P)^2 + 3.5145P] where P = (Fo^2 + 2Fc^2)/3
S = 1.18	(Δ/σ)max < 0.001
2986 reflections	Δρmax = 2.13 e Å^−3
164 parameters	Δρmin = −2.04 e Å^−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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
I1	0.70973 (4)	0.71365 (4)	−0.00068 (3)	0.01542 (11)
I2	0.41474 (4)	0.29786 (4)	0.38847 (3)	0.01461 (11)
O1	−0.2479 (5)	0.9555 (5)	0.2414 (4)	0.0192 (8)
O5	0.1516 (6)	0.9170 (5)	0.1003 (4)	0.0200 (8)
O6	−0.1900 (5)	0.9987 (4)	0.5039 (3)	0.0148 (7)
O7	0.1061 (5)	0.6852 (5)	0.4887 (3)	0.0175 (7)
Ca1	0.05899 (13)	0.88510 (11)	0.32050 (9)	0.01136 (19)
O4	0.0032 (5)	1.1833 (5)	0.2750 (4)	0.0160 (7)
O8	0.2502 (5)	0.6948 (5)	−0.0963 (4)	0.0189 (7)
O3	0.3979 (5)	0.7686 (6)	0.2948 (4)	0.0238 (8)
O2	0.0588 (6)	0.6331 (5)	0.2293 (4)	0.0226 (8)
H4A	0.079 (7)	1.231 (7)	0.245 (6)	0.016 (16)*
H5A	0.155 (11)	1.002 (4)	0.063 (6)	0.028 (19)*
H6A	−0.238 (8)	0.931 (6)	0.538 (7)	0.04 (2)*
H6B	−0.274 (7)	1.080 (5)	0.486 (8)	0.04 (2)*
H7B	0.084 (11)	0.713 (8)	0.562 (2)	0.04 (2)*
H7A	0.175 (13)	0.591 (5)	0.489 (7)	0.07 (3)*
H1A	−0.345 (6)	1.030 (6)	0.254 (6)	0.027 (19)*
H1B	−0.251 (10)	0.919 (9)	0.174 (4)	0.05 (3)*
H3A	0.468 (10)	0.749 (12)	0.230 (4)	0.06 (3)*
H5B	0.208 (15)	0.843 (6)	0.054 (6)	0.08 (4)*
H2A	0.001 (12)	0.620 (11)	0.172 (8)	0.08 (4)*
H3B	0.464 (10)	0.749 (15)	0.354 (5)	0.09 (4)*
H2B	0.150 (9)	0.552 (7)	0.235 (9)	0.06 (3)*
H8B	0.354 (5)	0.683 (9)	−0.136 (6)	0.018 (17)*
H8A	0.250 (11)	0.602 (4)	−0.073 (7)	0.024 (18)*
H4B	−0.044 (14)	1.186 (13)	0.208 (5)	0.06 (3)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
I1	0.01371 (17)	0.01851 (18)	0.01503 (17)	−0.00563 (12)	−0.00141 (11)	−0.00335 (12)
I2	0.00936 (16)	0.01374 (17)	0.01892 (18)	0.00038 (11)	−0.00382 (11)	−0.00194 (12)
O1	0.0092 (16)	0.0234 (19)	0.025 (2)	−0.0009 (14)	−0.0058 (14)	−0.0127 (15)
O5	0.0221 (19)	0.0190 (19)	0.0172 (18)	−0.0040 (15)	0.0007 (14)	−0.0014 (14)
O6	0.0079 (15)	0.0166 (17)	0.0186 (17)	−0.0008 (13)	−0.0034 (13)	0.0000 (13)
O7	0.0170 (17)	0.0147 (17)	0.0165 (18)	0.0020 (14)	−0.0008 (14)	−0.0036 (13)
Ca1	0.0080 (4)	0.0120 (4)	0.0132 (4)	−0.0009 (3)	−0.0029 (3)	−0.0018 (3)
O4	0.0140 (17)	0.0163 (17)	0.0184 (18)	−0.0051 (13)	−0.0033 (14)	0.0010 (14)
O8	0.0167 (18)	0.0169 (18)	0.0231 (19)	−0.0051 (14)	−0.0012 (15)	−0.0004 (15)
O3	0.0100 (17)	0.038 (2)	0.0198 (19)	−0.0011 (16)	0.0003 (14)	−0.0023 (17)
O2	0.025 (2)	0.0156 (18)	0.027 (2)	−0.0017 (15)	−0.0123 (16)	−0.0065 (15)

Geometric parameters (Å, º)

Ca1—O1	2.409 (4)	Ca1—O6	2.588 (4)
Ca1—O2	2.442 (4)	Ca1—O6^i	2.593 (4)
Ca1—O3	2.414 (4)	Ca1—O7	2.383 (4)
Ca1—O4	2.496 (4)	Ca1—O6^i	2.593 (4)
Ca1—O5	2.413 (4)	Ca1—Ca1^i	4.339 (2)
Ca1—O6—Ca1^i	113.76 (13)	O3—Ca1—O6	136.08 (13)
O7—Ca1—O1	114.68 (15)	O2—Ca1—O6	118.41 (14)
O7—Ca1—O5	140.93 (14)	O4—Ca1—O6	80.31 (12)
O1—Ca1—O5	81.07 (14)	O7—Ca1—O6^i	73.43 (13)
O7—Ca1—O3	79.41 (14)	O1—Ca1—O6^i	132.70 (12)
O1—Ca1—O3	151.32 (14)	O5—Ca1—O6^i	123.34 (13)
O5—Ca1—O3	73.52 (14)	O3—Ca1—O6^i	74.09 (13)
O7—Ca1—O2	74.52 (14)	O2—Ca1—O6^i	143.70 (13)
O1—Ca1—O2	76.94 (13)	O4—Ca1—O6^i	71.54 (12)
O5—Ca1—O2	74.97 (15)	O6—Ca1—O6^i	66.24 (13)
O3—Ca1—O2	83.70 (15)	O7—Ca1—Ca1^i	69.26 (9)
O7—Ca1—O4	141.83 (13)	O1—Ca1—Ca1^i	103.02 (10)
O1—Ca1—O4	79.94 (13)	O5—Ca1—Ca1^i	145.08 (11)
O5—Ca1—O4	73.51 (13)	O3—Ca1—Ca1^i	105.41 (11)
O3—Ca1—O4	104.77 (14)	O2—Ca1—Ca1^i	139.94 (12)
O2—Ca1—O4	143.25 (14)	O4—Ca1—Ca1^i	73.17 (9)
O7—Ca1—O6	72.05 (12)	O6—Ca1—Ca1^i	33.16 (8)
O1—Ca1—O6	72.44 (12)	O6^i—Ca1—Ca1^i	33.08 (8)
O5—Ca1—O6	145.51 (13)

Symmetry code: (i) −x, −y+2, −z+1.

(CaI2_7H2O_200K) Calccium iodide heptahydrate

Crystal data

CaI2·7H2O	F(000) = 1568
Mr = 419.99	Dx = 2.345 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
a = 9.841 (2) Å	Cell parameters from 1295 reflections
b = 16.530 (5) Å	θ = 1.9–29.2°
c = 14.639 (5) Å	µ = 5.71 mm^−1
β = 92.17 (2)°	T = 200 K
V = 2379.7 (12) Å^3	Needle, colurless
Z = 8	0.57 × 0.37 × 0.16 mm

Data collection

Stoe IPDS 2 diffractometer	5066 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.116
Detector resolution: 6.67 pixels mm^-1	θmax = 27.5°, θmin = 1.9°
rotation scans	h = −11→11
4198 measured reflections	k = −19→19
5443 independent reflections	l = −17→17

Refinement

Refinement on F^2	Hydrogen site location: difference Fourier map
Least-squares matrix: full	All H-atom parameters refined
R[F^2 > 2σ(F^2)] = 0.030	w = 1/[σ^2(Fo^2) + (0.0411P)^2 + 5.2685P] where P = (Fo^2 + 2Fc^2)/3
wR(F^2) = 0.075	(Δ/σ)max = 0.001
S = 1.16	Δρmax = 2.25 e Å^−3
5443 reflections	Δρmin = −2.00 e Å^−3
294 parameters	Extinction correction: SHELXL2012 (Sheldrick, 2008), Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
39 restraints	Extinction coefficient: 0.00101 (10)

Special details

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 (Ų)

	x	y	z	Uiso*/Ueq
I1	0.14520 (3)	0.13652 (2)	0.41798 (2)	0.02303 (8)
I2	0.33768 (3)	0.41725 (2)	0.55691 (2)	0.02378 (8)
I3	0.17568 (3)	0.65594 (2)	0.44244 (2)	0.02195 (8)
I4	0.35412 (3)	0.61134 (2)	0.08217 (2)	0.02417 (8)
Ca1	0.03595 (7)	0.10355 (4)	0.75322 (4)	0.01394 (14)
Ca2	0.45274 (7)	0.15255 (4)	0.73346 (4)	0.01367 (13)
O1	0.2431 (3)	0.16424 (15)	0.83506 (16)	0.0157 (5)
O2	0.2471 (3)	0.08905 (15)	0.65216 (16)	0.0159 (5)
O3	0.4368 (3)	0.20886 (17)	0.58156 (17)	0.0228 (6)
O4	0.5820 (3)	0.05073 (17)	0.64744 (18)	0.0213 (5)
O5	−0.1843 (3)	0.04501 (19)	0.77474 (19)	0.0266 (6)
O6	0.5528 (3)	0.1703 (3)	0.8822 (2)	0.0367 (8)
O7	0.6700 (3)	0.2140 (2)	0.7149 (2)	0.0295 (7)
O8	0.0835 (3)	0.23422 (18)	0.6800 (2)	0.0270 (6)
O9	0.4100 (3)	0.01968 (18)	0.8038 (2)	0.0264 (6)
O10	0.0411 (3)	0.04969 (17)	0.90690 (17)	0.0217 (5)
O11	−0.0688 (3)	0.0827 (2)	0.60647 (19)	0.0319 (7)
O12	0.1111 (4)	−0.03795 (19)	0.7466 (2)	0.0369 (8)
O13	−0.0896 (3)	0.21002 (17)	0.83495 (18)	0.0221 (5)
O14	0.3732 (5)	0.29358 (19)	0.7455 (2)	0.0405 (9)
H4A	0.544 (6)	0.008 (2)	0.632 (4)	0.08 (3)*
H2B	0.239 (7)	0.113 (3)	0.6027 (18)	0.056 (19)*
H2A	0.263 (5)	0.0413 (10)	0.641 (3)	0.034 (14)*
H12B	0.116 (8)	−0.070 (3)	0.790 (3)	0.07 (2)*
H6A	0.539 (7)	0.141 (4)	0.926 (3)	0.07 (2)*
H5A	−0.199 (5)	0.013 (2)	0.816 (2)	0.031 (14)*
H7A	0.688 (5)	0.244 (3)	0.673 (2)	0.040 (15)*
H11B	−0.038 (7)	0.106 (3)	0.562 (3)	0.07 (2)*
H1B	0.226 (4)	0.2111 (10)	0.849 (3)	0.018 (11)*
H14B	0.384 (8)	0.328 (5)	0.706 (6)	0.08 (2)*
H1A	0.259 (8)	0.139 (3)	0.8828 (19)	0.08 (3)*
H4B	0.624 (5)	0.066 (3)	0.603 (2)	0.038 (15)*
H3A	0.471 (6)	0.186 (3)	0.539 (2)	0.046 (17)*
H13B	−0.037 (6)	0.247 (3)	0.846 (4)	0.08 (3)*
H13A	−0.121 (5)	0.196 (3)	0.8838 (19)	0.042 (16)*
H9A	0.456 (5)	−0.004 (3)	0.844 (3)	0.06 (2)*
H7B	0.733 (4)	0.217 (3)	0.753 (3)	0.044 (16)*
H10B	0.016 (7)	0.077 (4)	0.950 (3)	0.07 (2)*
H10A	0.098 (6)	0.017 (3)	0.928 (4)	0.08 (2)*
H5B	−0.247 (4)	0.041 (3)	0.737 (3)	0.052 (18)*
H12A	0.085 (13)	−0.064 (4)	0.701 (3)	0.18 (6)*
H8A	0.148 (4)	0.264 (3)	0.694 (5)	0.08 (3)*
H8B	0.031 (4)	0.261 (3)	0.647 (3)	0.036 (15)*
H14A	0.385 (12)	0.313 (7)	0.800 (8)	0.15 (4)*
H3B	0.410 (6)	0.2529 (19)	0.563 (3)	0.06 (2)*
H11A	−0.102 (8)	0.040 (2)	0.588 (4)	0.09 (3)*
H6B	0.605 (7)	0.206 (4)	0.899 (4)	0.11 (3)*
H9B	0.354 (6)	−0.013 (3)	0.783 (4)	0.08 (2)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
I1	0.03021 (14)	0.02335 (14)	0.01554 (12)	−0.00095 (9)	0.00105 (9)	0.00512 (9)
I2	0.03266 (14)	0.02348 (14)	0.01462 (12)	0.00927 (10)	−0.00691 (9)	−0.00515 (8)
I3	0.02795 (14)	0.02280 (13)	0.01493 (12)	−0.00576 (9)	−0.00134 (9)	0.00436 (8)
I4	0.03271 (15)	0.01948 (13)	0.02083 (13)	0.00062 (9)	0.00771 (10)	0.00445 (9)
Ca1	0.0150 (3)	0.0171 (3)	0.0097 (3)	−0.0004 (2)	−0.0005 (2)	0.0010 (2)
Ca2	0.0159 (3)	0.0163 (3)	0.0087 (3)	−0.0010 (2)	−0.0005 (2)	0.0006 (2)
O1	0.0185 (11)	0.0162 (12)	0.0123 (11)	0.0016 (9)	−0.0013 (9)	−0.0007 (9)
O2	0.0216 (12)	0.0151 (11)	0.0107 (11)	0.0014 (10)	−0.0008 (9)	0.0014 (9)
O3	0.0359 (15)	0.0205 (13)	0.0123 (11)	0.0069 (11)	0.0029 (11)	0.0006 (10)
O4	0.0225 (13)	0.0244 (14)	0.0173 (12)	0.0012 (11)	0.0033 (10)	−0.0018 (10)
O5	0.0233 (14)	0.0378 (16)	0.0184 (13)	−0.0109 (12)	−0.0017 (11)	0.0097 (12)
O6	0.0310 (16)	0.063 (2)	0.0159 (14)	−0.0126 (16)	−0.0041 (12)	0.0004 (14)
O7	0.0241 (14)	0.0415 (18)	0.0227 (14)	−0.0144 (13)	−0.0009 (11)	0.0097 (13)
O8	0.0309 (15)	0.0227 (14)	0.0273 (15)	0.0048 (12)	−0.0007 (12)	0.0096 (12)
O9	0.0374 (16)	0.0222 (14)	0.0192 (13)	0.0037 (12)	−0.0034 (12)	0.0073 (11)
O10	0.0285 (14)	0.0228 (14)	0.0137 (12)	0.0043 (11)	−0.0003 (10)	0.0040 (10)
O11	0.0315 (16)	0.050 (2)	0.0137 (13)	−0.0127 (14)	−0.0021 (11)	0.0010 (13)
O12	0.066 (2)	0.0197 (14)	0.0262 (16)	0.0043 (15)	0.0208 (16)	0.0030 (12)
O13	0.0239 (13)	0.0248 (14)	0.0176 (12)	−0.0005 (11)	0.0029 (10)	−0.0021 (11)
O14	0.085 (3)	0.0156 (14)	0.0228 (15)	−0.0001 (15)	0.0273 (17)	0.0007 (12)

Geometric parameters (Å, º)

Ca1—O1	2.532 (3)	Ca2—O2	2.536 (3)
Ca1—O2	2.607 (3)	Ca2—O3	2.410 (3)
Ca1—O5	2.406 (3)	Ca2—O4	2.481 (3)
Ca1—O8	2.464 (3)	Ca2—O6	2.373 (3)
Ca1—O10	2.418 (3)	Ca2—O7	2.392 (3)
Ca1—O11	2.373 (3)	Ca2—O9	2.469 (3)
Ca1—O12	2.456 (3)	Ca2—O14	2.468 (3)
Ca1—O13	2.484 (3)	Ca1—Ca2	4.2017 (13)
Ca2—O1	2.596 (3)
O11—Ca1—O5	72.38 (11)	O6—Ca2—O3	143.97 (12)
O11—Ca1—O10	141.45 (11)	O7—Ca2—O3	76.02 (11)
O5—Ca1—O10	73.59 (10)	O6—Ca2—O14	86.51 (14)
O11—Ca1—O12	86.96 (13)	O7—Ca2—O14	83.92 (13)
O5—Ca1—O12	84.05 (12)	O3—Ca2—O14	72.03 (10)
O10—Ca1—O12	71.97 (10)	O6—Ca2—O9	78.39 (12)
O11—Ca1—O8	79.43 (12)	O7—Ca2—O9	126.33 (11)
O5—Ca1—O8	126.61 (11)	O3—Ca2—O9	136.24 (10)
O10—Ca1—O8	136.87 (10)	O14—Ca2—O9	138.69 (11)
O12—Ca1—O8	139.04 (11)	O6—Ca2—O4	110.28 (12)
O11—Ca1—O13	109.39 (11)	O7—Ca2—O4	75.70 (11)
O5—Ca1—O13	75.80 (11)	O3—Ca2—O4	79.08 (10)
O10—Ca1—O13	78.82 (10)	O14—Ca2—O4	147.91 (10)
O12—Ca1—O13	148.21 (10)	O9—Ca2—O4	72.95 (10)
O8—Ca1—O13	72.21 (10)	O6—Ca2—O2	141.05 (11)
O11—Ca1—O1	143.17 (10)	O7—Ca2—O2	145.43 (10)
O5—Ca1—O1	144.16 (9)	O3—Ca2—O2	72.78 (10)
O10—Ca1—O1	73.59 (9)	O14—Ca2—O2	100.08 (12)
O12—Ca1—O1	99.09 (12)	O9—Ca2—O2	71.46 (9)
O8—Ca1—O1	72.29 (9)	O4—Ca2—O2	84.05 (9)
O13—Ca1—O1	84.12 (9)	O6—Ca2—O1	77.08 (10)
O11—Ca1—O2	78.54 (10)	O7—Ca2—O1	140.05 (10)
O5—Ca1—O2	141.17 (10)	O3—Ca2—O1	118.32 (9)
O10—Ca1—O2	120.32 (9)	O14—Ca2—O1	68.12 (10)
O12—Ca1—O2	69.05 (10)	O9—Ca2—O1	71.08 (9)
O8—Ca1—O2	70.44 (9)	O4—Ca2—O1	140.81 (9)
O13—Ca1—O2	139.49 (9)	O2—Ca2—O1	70.26 (8)
O1—Ca1—O2	70.14 (8)	O6—Ca2—Ca1	109.44 (9)
O11—Ca1—Ca2	110.95 (8)	O7—Ca2—Ca1	165.65 (9)
O5—Ca1—Ca2	166.78 (8)	O3—Ca2—Ca1	96.22 (8)
O10—Ca1—Ca2	98.56 (7)	O14—Ca2—Ca1	82.18 (10)
O12—Ca1—Ca2	83.38 (10)	O9—Ca2—Ca1	67.52 (8)
O8—Ca1—Ca2	66.37 (7)	O4—Ca2—Ca1	115.13 (7)
O13—Ca1—Ca2	113.67 (7)	O2—Ca2—Ca1	35.79 (6)
O1—Ca1—Ca2	35.49 (6)	O1—Ca2—Ca1	34.48 (6)
O2—Ca1—Ca2	34.66 (6)	Ca1—O1—Ca2	110.03 (9)
O6—Ca2—O7	73.14 (11)	Ca2—O2—Ca1	109.55 (9)

(CaI2_6H2O_153K) Calcium iodide 6.5-hydrate

Crystal data

CaI2·6.5H2O	F(000) = 1528
Mr = 200.99	Dx = 2.387 Mg m^−3
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
a = 16.466 (3) Å	Cell parameters from 4977 reflections
b = 8.2919 (11) Å	θ = 2.8–29.6°
c = 17.947 (3) Å	µ = 5.93 mm^−1
β = 111.045 (12)°	T = 153 K
V = 2286.9 (7) Å^3	Plate, colourless
Z = 8	0.54 × 0.30 × 0.06 mm

Data collection

Stoe IPDS 2 diffractometer	2603 independent reflections
Radiation source: fine-focus sealed tube	2329 reflections with I > 2σ(I)
Detector resolution: 6.67 pixels mm^-1	Rint = 0.081
rotation method scans	θmax = 27.5°, θmin = 2.4°
Absorption correction: integration (Coppens, 1970)	h = −21→21
Tmin = 0.136, Tmax = 0.698	k = −10→10
2626 measured reflections	l = −23→23

Refinement

Refinement on F^2	Hydrogen site location: difference Fourier map
Least-squares matrix: full	All H-atom parameters refined
R[F^2 > 2σ(F^2)] = 0.026	w = 1/[σ^2(Fo^2) + (0.0397P)^2 + 14.5175P] where P = (Fo^2 + 2Fc^2)/3
wR(F^2) = 0.072	(Δ/σ)max = 0.001
S = 1.11	Δρmax = 0.95 e Å^−3
2603 reflections	Δρmin = −1.18 e Å^−3
140 parameters	Extinction correction: SHELXL2012 (Sheldrick, 2008), Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
18 restraints	Extinction coefficient: 0.00069 (7)

Special details

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 (Ų)

	x	y	z	Uiso*/Ueq
I1	0.18634 (2)	0.68576 (3)	0.09222 (2)	0.01950 (10)
I2	0.05829 (2)	0.18735 (3)	0.13858 (2)	0.02066 (10)
Ca1	0.39445 (4)	0.20464 (8)	0.15575 (4)	0.01167 (15)
O1	0.30981 (19)	0.3519 (4)	0.22079 (17)	0.0200 (6)
O2	0.44427 (18)	0.0993 (3)	0.29529 (16)	0.0153 (5)
O3	0.5000	0.3963 (4)	0.2500	0.0137 (7)
O4	0.36041 (19)	0.4564 (3)	0.07631 (18)	0.0200 (6)
O5	0.24556 (18)	0.1607 (4)	0.08098 (18)	0.0220 (6)
O6	0.4276 (2)	0.1424 (4)	0.03938 (18)	0.0236 (6)
O7	0.38139 (19)	−0.0824 (3)	0.1467 (2)	0.0230 (6)
H6A	0.413 (5)	0.060 (5)	0.013 (3)	0.06 (2)*
H3A	0.520 (3)	0.455 (5)	0.224 (3)	0.029 (14)*
H4B	0.405 (2)	0.503 (6)	0.078 (4)	0.048 (19)*
H4A	0.329 (3)	0.524 (5)	0.085 (4)	0.040 (17)*
H1B	0.302 (3)	0.348 (7)	0.2634 (17)	0.033 (15)*
H5A	0.209 (4)	0.173 (10)	0.102 (5)	0.08 (3)*
H6B	0.446 (4)	0.206 (5)	0.014 (3)	0.037 (17)*
H5B	0.214 (3)	0.126 (8)	0.0375 (19)	0.041 (17)*
H7A	0.3327 (12)	−0.122 (5)	0.129 (3)	0.027 (14)*
H7B	0.416 (2)	−0.152 (4)	0.147 (3)	0.034 (16)*
H1A	0.275 (4)	0.418 (7)	0.193 (3)	0.06 (2)*
H2A	0.423 (4)	0.136 (5)	0.326 (3)	0.033 (15)*
H2B	0.443 (4)	0.0005 (13)	0.299 (3)	0.043 (18)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
I1	0.01961 (15)	0.02108 (15)	0.02089 (15)	−0.00331 (9)	0.01099 (10)	−0.00263 (9)
I2	0.02118 (15)	0.01815 (15)	0.02717 (16)	0.00126 (9)	0.01415 (11)	0.00527 (9)
Ca1	0.0107 (3)	0.0124 (3)	0.0114 (3)	−0.0003 (2)	0.0033 (3)	−0.0005 (2)
O1	0.0228 (14)	0.0227 (14)	0.0167 (14)	0.0058 (11)	0.0097 (12)	0.0014 (11)
O2	0.0177 (12)	0.0161 (13)	0.0145 (12)	0.0020 (10)	0.0087 (10)	0.0021 (10)
O3	0.0178 (17)	0.0088 (16)	0.0150 (17)	0.000	0.0066 (14)	0.000
O4	0.0204 (13)	0.0164 (13)	0.0231 (14)	0.0008 (11)	0.0076 (11)	0.0008 (11)
O5	0.0128 (13)	0.0322 (16)	0.0193 (14)	−0.0016 (12)	0.0035 (11)	−0.0052 (12)
O6	0.0312 (16)	0.0253 (15)	0.0177 (14)	0.0001 (13)	0.0130 (12)	−0.0005 (12)
O7	0.0189 (13)	0.0146 (13)	0.0352 (16)	−0.0022 (11)	0.0094 (12)	−0.0038 (12)

Geometric parameters (Å, º)

Ca1—O1	2.442 (3)	Ca1—O6	2.397 (3)
Ca1—O2	2.496 (3)	Ca1—O7	2.390 (3)
Ca1—O2^i	2.629 (3)	Ca1—Ca1^i	3.8834 (16)
Ca1—O3	2.509 (2)	O2—Ca1^i	2.629 (3)
Ca1—O4	2.476 (3)	O3—Ca1^i	2.509 (2)
Ca1—O5	2.363 (3)
O5—Ca1—O7	76.00 (11)	O4—Ca1—O3	79.23 (9)
O5—Ca1—O6	89.24 (11)	O2—Ca1—O3	69.31 (8)
O7—Ca1—O6	76.68 (11)	O5—Ca1—O2^i	148.90 (10)
O5—Ca1—O1	72.22 (10)	O7—Ca1—O2^i	75.37 (9)
O7—Ca1—O1	118.52 (11)	O6—Ca1—O2^i	72.59 (10)
O6—Ca1—O1	150.66 (11)	O1—Ca1—O2^i	133.45 (9)
O5—Ca1—O4	80.14 (11)	O4—Ca1—O2^i	117.72 (9)
O7—Ca1—O4	143.53 (11)	O2—Ca1—O2^i	67.66 (10)
O6—Ca1—O4	75.82 (10)	O3—Ca1—O2^i	67.23 (8)
O1—Ca1—O4	78.68 (10)	O5—Ca1—Ca1^i	156.41 (8)
O5—Ca1—O2	114.58 (10)	O7—Ca1—Ca1^i	95.15 (8)
O7—Ca1—O2	73.08 (10)	O6—Ca1—Ca1^i	110.26 (9)
O6—Ca1—O2	134.69 (10)	O1—Ca1—Ca1^i	93.99 (7)
O1—Ca1—O2	74.56 (9)	O4—Ca1—Ca1^i	116.64 (7)
O4—Ca1—O2	142.89 (10)	O2—Ca1—Ca1^i	42.03 (6)
O5—Ca1—O3	143.80 (10)	O3—Ca1—Ca1^i	39.29 (6)
O7—Ca1—O3	134.44 (10)	O2^i—Ca1—Ca1^i	39.48 (6)
O6—Ca1—O3	113.84 (9)	Ca1—O2—Ca1^i	98.49 (9)
O1—Ca1—O3	74.76 (8)	Ca1^i—O3—Ca1	101.41 (13)

Symmetry code: (i) −x+1, y, −z+1/2.