Synthesis methods for Ce(CrO4)2 · xH 2O and crystal structures of K2CrSO7, (NH 4)2Cr2O7 and Na2Cr 2O7 · 2H2O

Article abstract of DOI:10.1515/znb-2007-0604

New and quick methods to synthesize Ce(CrO₄)₂ · 2H₂O and Ce(CrO₄)₂ · H ₂O, giving high yields, are described. The methods are based on exchange reactions by refluxing in water or on solid state reactions. The first crystal structure containing a chromatosulfato ion is presented. K ₂CrSO₇ belongs to space group P2₁/n with a = 7.4024(1), b = 7.3908(1), c = 12.9883(2) A?, β = 90.021(1)° and Z = 4. The CrSO₇^2- ion, consisting of one chromate group sharing one oxygen atom with one sulfate group, has a pseudo syn-C_2v conformation with eclipsed oxygen atoms. K₂CrSO₇ forms a three dimensional network of CrSO₇^2- ions held together by the charge balancing potassium ions, with the general structural features common with dichromate-like structures. The redetermination of the structures of (NH₄)₂Cr₂O₇ (space group C2/c, with hydrogen atoms located) and Na₂Cr₂O₇ · 2H₂O (space group P2₁, with hydrogen atoms located and the absolute structure established) are reported.

Full text of DOI:10.1515/znb-2007-0604

Synthesis Methods for Ce(CrO4)2 · xH2O and Crystal Structures of
K2CrSO7, (NH4)2Cr2O7 and Na2Cr2O7 · 2H2O
Barbara M. Casaria, Annika K. Erikssonb, and Vratislav Langerb
a Department of Chemistry, Inorganic Chemistry, Go¨teborg University, SE-412 96 Go¨teborg, Sweden
b Environmental Inorganic Chemistry, Department of Chemical and Biological Engineering,
Chalmers University of Technology, SE-412 96 Go¨teborg, Sweden
Reprint requests to B. M. Casari. Fax: +46(0)317722853. E-mail: casari@chem.gu.se
Z. Naturforsch. 2007, 62b, 771 – 777; received January 1, 2007
New and quick methods to synthesize Ce(CrO4)2 · 2H2O and Ce(CrO4)2 · H2O, giving high yields,
are described. The methods are based on exchange reactions by refluxing in water or on solid state
reactions. The first crystal structure containing a chromatosulfato ion is presented. K2CrSO7 belongs
◦
˚
to space group P21/n with a = 7.4024(1), b = 7.3908(1), c = 12.9883(2) A, β = 90.021(1) and Z = 4.
The CrSO72− ion, consisting of one chromate group sharing one oxygen atom with one sulfate group,
has a pseudo syn-C2v conformation with eclipsed oxygen atoms. K2CrSO7 forms a three dimensional
2−
network of CrSO7 ions held together by the charge balancing potassium ions, with the general
structural features common with dichromate-like structures. The redetermination of the structures of
(NH4)2Cr2O7 (space group C2/c, with hydrogen atoms located) and Na2Cr2O7 · 2H2O (space group
P21, with hydrogen atoms located and the absolute structure established) are reported.
Key words: Hydrated Cerium Chromates, Chromatosulfate, Dichromates, Oxidizing Agents,
Single Crystal X-Ray Diffraction
2−
,
Introduction
The chromate, CrO42−, and dichromate, Cr2O7
ions form the basis for a series of industrially important
salts. Solving the crystal structure of (NH4)2Cr2O7,
Bystro¨m and Wilhelmi [7] made the first structure de-
termination of a compound with the stoichiometric for-
mula A2M2O7, where A is a large cation and M is a
small atom with high formal oxidation state. These
structures contain M2O7 units consisting of two cor-
ner sharing MO4 tetrahedra. Different packing motifs
of M2O7 units give rise to several polymorphic forms
and many new types of A2M2O7 structures have been
reported since then. Brown and Calvo [8] reported a
scheme of the relation between these structure types,
and Clark and Morely [9] published a review on in-
organic pyrocompounds, Ma(X2O7)b. Sodium dichro-
mate has been reported in two triclinic modifica-
tions [10]. Three polymorphic forms for potassium
dichromate [11] and four modifications for rubid-
ium dichromate [12] have been reported. One crys-
tal structure of ammonium dichromate has been pub-
lished [7, 13]. Sporadic cases of hydrated dichromates
have been structurally characterized until now: the
sodium dichromate tetrahydrate [14], three modifica-
tions of lithium dichromate dihydrate [15] and the
Chromium(VI) compounds continue to attract inter-
est as they represent the most widely used group of
oxidizing agents in organic chemistry, capable of ox-
idizing almost every organic functional group. Oxida-
tion by cerium(IV) is also a valuable tool [1] in or-
ganic chemistry. Various Ce-Cr-O catalysts of different
Cr content have been synthesized [2] and used in ox-
idative dehydrogenation of lower alkanes, a subject of
growing interest as a source of inexpensive olefins for
industrial applications [3]. Nitrato cerium(IV) chro-
mates(VI) have been used as versatile oxidants or
as mild, efficient, and inexpensive catalysts for ox-
idative deprotection [4]. The combination of Ce(IV)
and Cr(VI) in order to synthesize different cerium
chromates may produce new powerful oxidation tools
with unique properties. Investigations on cerium chro-
mates were started by Lindgren [5] who published
Ce(CrO4)2 · 2H2O, the only structure determination re-
ported until recently when Kolitsch and Schwendt-
ner [6] reported the structure of Ce(CrO4)2 · H2O.
Quick and easy reaction routes for these compounds
are presented in this paper.
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B. M. Casari et al. · Ce(CrO4)2 · xH2O and K2CrSO7, (NH4)2Cr2O7 and Na2Cr2O7 · 2H2O
˚
Table 1. Bond lengths (A) in 3.
sodium dichromate dihydrate [16]. Only three struc-
tures with pyrosulfate anions were known [17] until
recently when Sta˚hl et al. [18] published the structures
of Na2S2O7, K2S2O7 and KNaS2O7.
Cr1–O1
Cr1–O2
Cr1–O3
Cr1–O4
K1–O1ii
K1–O1iii
K1–O2
1.595(5)
1.604(6)
1.592(6)
1.807(6)
2.800(5)
2.810(5)
2.870(6)
2.966(6)
2.804(6)
2.821(6)
2.828(7)
2.747(6)
S1–O4
S1–O5
S1–O6
S1–O7
1.577(6)
1.471(6)
1.495(6)
1.481(6)
2.755(6)
2.722(6)
3.117(5)
2.966(7)
3.111(7)
2.843(7)
2.921(7)
2.809(6)
K2–O1i
K2–O2
K2–O4iv
K2–O5iv
K2–O5vi
K2–O6iii
K2–O6vi
K2–O7i
There is evidence for the existence of a “chromo sul-
fate” anion [19], but no structures of compounds con-
2−
taining CrSO7 ions have been reported until now.
K1–O2iii
K1–O3iv
K1–O5v
K1–O6
Here we present the crystal structure of K2CrSO7 and
the redetermination of the structures of (NH4)2Cr2O7
and Na2Cr2O7 · 2H2O.
K1–O7i
Symmetry transformations for equivalent atoms: x + 1, y, z; ii x +
i
Results and Discussion
iii
iv
1/2, −y + 1/2, z + 1/2; −x + 1, −y + 1, −z + 1; −x + 1, −y,
−z+1; v −x+1/2, y+1/2, −z+3/2; vi x+1/2, −y+1/2, z−1/2.
Synthesis methods for Ce(CrO4)2 · 2H2O (1) and
Ce(CrO4)2 · H2O (2)
tion was twinned, mimicking the orthorhombic sym-
metry due to the closeness of the β angle to 90◦, twin
New and quick methods to synthesize compounds 1
and 2, giving high yields, are described in the experi-
mental section. One method is based on exchange re-
actions from commercially available starting materials
by refluxing the reactants in water solution. The second
method is based on an addition reaction in the solid
state. Compound 1 has previously been synthesized by
Lindgren [5] from water solution by slow evaporation
at r. t. Compound 2 has unexpectedly been synthesized
by Kolitsch and Schwendtner [6] by slowly evaporat-
ing an aqueous solution, using a Ce(III) species and
CrO3, where the reaction involved a slow oxidation
of Ce(III) by Cr(VI), also encountered in our previous
work [20].
The structure of 1 is essentially different from that
of 2. Compound 1 is built up by layers of [Ce(CrO4)2-
(H2O)2]n held together by hydrogen bonds, while the
structure of 2 forms a three-dimensional network me-
diated by oxygen bridges. As a consequence of the
structural differences their properties differ. The den-
sity of 2 (3.75 g cm−3) is higher than that of 1
(3.37 g cm−3) and the solubility of 1 in water is much
higher than the solubility of 2.
¯
¯
law: [(1 0 0) (0 1 0) (0 0 1)]. The twin volume ratio
was refined to 0.505(4)/0.495(4). There are two potas-
sium cations and one chromatosulfato, CrSO72−, an-
2−
ion in the asymmetric unit. The CrSO7 ion, consist-
ing of one chromate tetrahedron sharing one oxygen
atom with one sulfate tetrahedron, has a pseudo syn-
C2v conformation with eclipsed oxygen atoms (Fig. 1).
This conformation is the usual one for both the dichro-
mate and the disulfate compounds. The Cr–O bridg-
ing distance is longer [d = 1.807(6) A] than the ter-
minal Cr–O distances with an average of 1.597(6) A.
The mean Cr–O distance within the chromium tetrahe-
dra (1.65(10) A) is in accordance with distances re-
ported for dichromate compounds [7, 10 – 16]. Also
the S–O bridging distance is longer [d = 1.577(6) A]
than the terminal distances which average to 1.48(1) A.
The mean S–O distance within the sulfate moiety
[1.50(5) A] is in accordance with distances within py-
rosulfate compounds [17, 18]. The bond-valence sums
are 6.08 and 5.84 valence units for Cr1 and S1, re-
spectively (using the parameters from Brown and Al-
termatt [21]). For a complete list of bond lengths see
Table 1. The Cr1–O4–S1 bond angle is 125.8(3)◦. The
potassium ions (K1 and K2) are in contact with eight
oxygen atoms at distances ranging between 2.722(6)
˚
˚
˚
˚
˚
˚
Fig. 1. Coordination
2−
geometry for CrSO7
˚
and 3.117(5) A (Table 1). The K1 and K2 ions connect
to six and five different CrSO7 units, respectively.
Each terminal oxygen atom within the CrSO7 units
in 3. The displacement
ellipsoids are drawn at
50 % probability level.
2−
2−
is linked to two or three potassium ions. The bridg-
ing oxygen atom, O4, has one cation contact, which is
common in most of the chromate-like structures [9] but
not found in the pyrosulfate structures [18].
Structural description of K2CrSO7 (3)
Compound 3 crystallizes in the space group P21/n
with a = 7.4024(1), b = 7.3908(1), c = 12.9883(2) A,
˚
Compound 3 forms a three dimensional network
2−
β = 90.021(1)◦ and Z = 4. The crystal under investiga- of CrSO7
ions held together by the charge bal-
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B. M. Casari et al. · Ce(CrO4)2 · xH2O and K2CrSO7, (NH4)2Cr2O7 and Na2Cr2O7 · 2H2O
773
2−
Fig. 3. Packing of the Cr2O7
units and the ammonium
ions in 4 showing the hydrogen bonding contacts with dashed
lines.
2−
Fig. 2. Packing of the CrSO7 units and the potassium ions
for 3, the purple (dark) tetrahedra are chromate units and the
yellow tetrahedra (light) are sulfate units.
ancing potassium ions (Fig. 2), with structural fea-
tures common with A2M2O7 compounds. Brown and
Calvo [8] proposed a scheme for classifying A2M2O7
structure types, where the structures are described in
terms of the possible ways of stacking sheets. These
sheets are composed of centrosymmetrically related
A2M2O7 groups forming a basic unit. The structure
of 3 can be described in terms of two alternating
sheets parallel to the ab plane, with the composi-
tion [K2CrSO7]n (Fig. 2). In this structure, adjacent
sheets are related by two-fold screw axes between them
and glide planes perpendicular to them. According to
the scheme proposed by Brown and Calvo [8], who
predicted this structure type before it had been ob-
served, this structure belongs to type VII. A high tem-
perature phase of K2Cr2O7 belonging to this struc-
ture type is supposed to exist [11a, f], but its struc-
ture has not been solved. However, the structure of
Rb2Cr2O7 (space group P21/n) [12b] has the key pack-
Fig. 4. View of 4 in the c direction showing adjacent sheets
with the composition [(NH4)2Cr2O7]n related by C-center-
ing.
ing features common with the structure of 3. The struc-
ture of K2S2O7 [18] belongs to the structure type
X [8] together with the structures of K2Cr2O7 [11e],
Rb2Cr2O7 [12c] and (NH4)2Cr2O7 (4) [7, 13]. Within
these structures the sheets are more symmetric, due to
the twofold axes through the bridging oxygen atoms,
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B. M. Casari et al. · Ce(CrO4)2 · xH2O and K2CrSO7, (NH4)2Cr2O7 and Na2Cr2O7 · 2H2O
˚
Table 2. Bond lengths (A) in 4 and 5.
oxygen atoms within this structure type do not con-
nect to cations, which is atypical for dichromate com-
pounds.
4
Cr2–O21
1.631(2)
1.616(2)
1.617(3)
1.800(2)
1.622(2)
1.627(3)
1.622(2)
1.800(2)
1.619(2)
1.628(2)
1.628(3)
Cr1–O1
Cr1–O2
Cr1–O3
Cr1–O4
5
1.7864(9)
1.6235(14)
1.6292(14)
1.6053(14)
Cr2–O22
Cr2–O23
Cr3–O30
Cr3–O31
Cr3–O32
Cr3–O33
Cr4–O30
Cr4–O41
Cr4–O42
Cr4–O43
Structural description of Na2Cr2O7 · 2H2O (5)
Neither e. s. d.’s nor anisotropic displacement pa-
rameters were given by Kharitonov et al. [16] in the pa-
per on the Na2Cr2O7 · 2H2O structure and the R value
was reported to be 0.083, based on film data. Here
we present a redetermination of the Na2Cr2O7 · 2H2O
structure where the hydrogen atoms have been located
and the absolute structure has been established. Com-
pound 5 belongs to the non-centrosymmetric space
group P21, with a = 6.1216(1), b = 10.7868(1), c =
Cr1–O10
Cr1–O11
Cr1–O12
Cr1–O13
Cr2–O10
1.794(2)
1.620(2)
1.626(3)
1.618(2)
1.817(2)
˚
Table 3. Hydrogen bonds for 4 (A and deg).
D–H···A
d(D–H)
0.83(2)
0.81(2)
0.82(2)
0.82(2)
0.81(2)
d(H···A)
2.04(2)
2.08(2)
2.29(3)
2.37(3)
2.14(2)
d(D···A)
2.832(2)
2.872(2)
2.939(2)
2.994(2)
2.902(2)
∠(DHA)
158(3)
167(3)
137(3)
134(3)
158(3)
N1–H1···O2
N1–H2···O3i
N1–H3···O3ii
N1–H3···O2iii
N1–H4···O3iv
◦
˚
12.7175(1) A, β = 95.080(1) and Z = 4. The struc-
i
Symmetry transformations used for equivalent atoms: −x + 1/2,
−y+ 1/2, −z + 1; ii x, y, z − 1; iii −x+ 1, y, −z + 1/2; iv x, −y+ 1,
z−1/2.
and adjacent sheets are related by a translation opera-
tion, see Figs. 3 and 4 for the packing of 4.
Structural description of (NH4)2Cr2O7 (4)
A redetermination of the structure of 4 [7, 13] with
the hydrogen atoms located is presented. Compound 4
belongs to the monoclinic space group C2/c, with a =
˚
13.2741(3), b = 7.4831(2), c = 7.7125(1) A, β =
93.305(1)◦ and Z = 4. The structure is composed of
ammonium cations and discrete chromate dimers, in
which the two CrO4 tetrahedra are related by a twofold
axis through the shared oxygen atom, O1. The Cr–O
˚
bridging distance is longer (d = 1.7865(9) A) than the
˚
terminal Cr–O bridging distances (dmean = 1.62(1) A)
and the mean Cr–O distance within the individual tetra-
˚
hedra is 1.66(8) A (Table 2). The tetrahedral ammo-
nium ions in 4 are surrounded by eight nearest oxy-
gen atoms belonging to six different dichromate units
˚
(distances range: 2.832(2)– 3.161(2) A). The hydro-
gen atoms in the ammonium ion show mono- (H1, H2
and H4) and bi-furcated (H3) interactions with oxygen
2−
atoms in the Cr2O7 units, presented in Fig. 3 and
Table 3. The structure can be regarded as sheets [8]
with the composition [(NH4)2Cr2O7]n, parallel to the
bc plane. The sheets have a twofold axis along b and a
glide plane along c, and adjacent sheets are related by
a C-centering translation (Fig. 4). This structure is iso-
morphous with its chemical analogues K2Cr2O7 [11e]
Fig. 5. View of the structure of 5 along the b (top) and c
(bottom) axis showing the hydrogen bonding contacts with
and Rb2Cr2O7 [12c] and K2S2O7 [18]. The bridging dashed lines.
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B. M. Casari et al. · Ce(CrO4)2 · xH2O and K2CrSO7, (NH4)2Cr2O7 and Na2Cr2O7 · 2H2O
775
˚
Table 4. Hydrogen bonds for 5 (A and deg).
in a crucible with a lid and heated in a furnace over the week-
end at 150 ◦C. The temperature was then raised to 188 ◦C for
19 h. The hygroscopic part of the powder was rinsed and the
remaining part was dried. Powder diffraction revealed that
the dark powder consisted mainly of Ce(CrO4)2 · 2H2O.
Ce(CrO4)2 · H2O (2): Powders of (NH4)2[Ce(NO3)6]
(0.50 g, 0.91 mmol) and CrO3 (0.28 g, 2.8 mmol) were mixed
in water (5.0 mL) and poured into a micro round-bottom flask
connected to a reflux water condenser. The reaction mix-
ture was refluxed for 24 h until dark red and bipyramidally
formed crystals of 2 were produced. Powder diffraction anal-
ysis showed evidence of a pure product.
K2CrSO7 (3): Crystals of K2Cr2O7 were formed during
an attempt to prepare hydrated cerium chromates. Ce(OH)4
was precipitated with ammonia as in the solid state synthesis
of 1. Ce(OH)4 (0.15 g, 0.95 mmol) was added to a saturated
solution of K2CrO4 (1.5 mL), then concentrated sulphuric
acid was added until the cerium hydroxide was completely
dissolved. An additional amount (1.5 mL) of saturated solu-
tion of K2CrO4 was then added. This particular sample was
left covered, and after a year light yellow-orange crystals,
shaped as parallelepipeds with square faces, started to peri-
odically form and dissolve. Finally, one of these metastable
crystals was suitable for single crystal X-ray analysis.
(NH4)2Cr2O7 (4): Crystals of 4 were produced during in-
vestigations on the CeO2-CrO3-H2O system. Ce(OH)4 was
produced using the same recipe as in the solid state synthe-
sis of 1. (NH4)2(CrO4)2 (2.0 g, 13.7 mmol) and Ce(OH)4
(1.0 g, 6.3 mmol) were added to water (20 mL). After stir-
ring, the solid residue was removed by filtration. Evaporation
resulted in an orange crystalline material. After recrystalliza-
tion from water solution, orange plate shaped single crystals
were formed.
D–H···A
d(D–H) d(H···A) d(D···A) ∠(DHA)
O1–H11···O41v
O1–H11···O22ii
O1–H12···O43ii
O1–H12···O31
O2–H21···O13iv
O2–H22···O11vi
O3–H31···O33i
O3–H32···O32ii
O4–H41···O10iii
O4–H42···O31iv
0.81(3)
0.81(3)
0.82(3)
0.82(3)
0.80(3)
0.83(3)
0.85(3)
0.86(3)
0.79(3)
0.82(3)
2.44(4)
2.46(4)
2.28(4)
2.58(5)
2.18(3)
2.06(3)
2.20(4)
2.23(3)
2.50(4)
2.21(3)
3.113(4)
3.025(4)
2.989(3)
3.076(4)
2.925(4)
2.865(4)
2.930(4)
2.991(4)
3.096(4)
3.005(4)
i
141(5)
128(4)
145(5)
120(4)
154(5)
164(5)
144(5)
147(5)
132(5)
162(5)
Symmetry transformations for equivalent atoms: −x, y − 1/2,
−z−1; ii −x− 1, y− 1/2, −z − 1; iii x, y− 1, z + 1; iv −x, y− 1/2,
−z; v −x−2, y−1/2, −z−1; vi −x+1, y−1/2, −z.
ture is composed of sodium cations, discrete chro-
mate dimers, joined by sharing corners, and wa-
ter molecules. There are two non-equivalent Cr2O7
units, four sodium atoms and four water molecules
in the asymmetric unit. The Cr–O bridging dis-
tances are longer (dmean = 1.80(1) A) than the ter-
minal Cr–O distances (dmean = 1.623(5) A). Despite
the variation of bond lengths, the mean Cr–O dis-
tance within the individual tetrahedra remains con-
stant (dmean = 1.668(8) A) (Table 2). Each sodium
ion within Na2Cr2O7 · 2H2O is connected to two wa-
ter molecules and four oxygen atoms belonging to four
different dichromate units (distances range: 2.344(3)–
˚
˚
˚
˚
2.512(3) A). The crystal structure of 5 can be de-
scribed as intercalating sheets in the ac plane of dis-
crete dichromate units, water molecules and sodium
ions (Fig. 5a). The water molecules in the ac plane
interact mainly with the adjacent layer of chromate
units (Fig. 5b), and the three dimensional framework is
formed by the ionic interactions between the chromate
groups and the potassium ions. The hydrogen bonding
contacts are listed in Table 4.
Na2Cr2O7 · 2H2O (5): A solution of Ce(CrO4)2 · 2H2O
(see synthesis of 1) (0.15 g, 0.37 mmol), NaCr2O7 (0.15 g,
0.57 mmol) and ten drops of hydrochloric acid (15 M) was
refluxed in a micro round bottom flask for 10 h. The mix-
ture was left to evaporate until orange plate shaped crystals
of Na2Cr2O7 · 2H2O were formed.
Experimental Section
Sample preparations
Single crystal X-ray analysis
Data were collected using a Siemens SMART CCD
diffractometer equipped with a Siemens LT-2A low temper-
ature device, at 22 ◦C for 3, at −90 ◦C for 4, and at −100 ◦C
for 5. Full spheres of the reciprocal space were scanned by
0.3◦ steps in ω with a crystal-to-detector distance of 3.97 cm
and exposure times per frame of 20 s for 3, 5 s for 4, and
1 s for 5. Preliminary orientation matrices were obtained us-
Ce(CrO4)2 · 2H2O (1), from water solution: Ce(SO4)2 ·
4H2O (0.50 g, 1.27 mmol), CrO3 (0.38 g, 3.8 mmol) and wa-
ter (5.0 mL) were mixed in a micro round bottom flask con-
nected to a reflux water condenser. The reaction mixture was
refluxed for 24 h until orange crystals of 1 were formed. Pow-
der diffraction analysis showed evidence of a pure product.
Ce(CrO4)2 · 2H2O (1), solid state synthesis: Ce(SO4)2 · ing SMART [22]. The collected frames were integrated with
4H2O (3.0 g, 7.5 mmol) was dissolved in water (20 mL) and the orientation matrices updated every 100 frames. Final cell
Ce(OH)4 was precipitated with 15 M ammonia. Ce(OH)4 and parameters were obtained by refinement on the position of
CrO3 (molar ratio 1 : 2) were milled in dry atmosphere, using 8192 (3), 6379 (4) and 7764 (5) reflections with I ≥ 10σ(I)
a glove bag filled with nitrogen gas. The sample was placed after integration of all the data using SAINT [22]. The data
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B. M. Casari et al. · Ce(CrO4)2 · xH2O and K2CrSO7, (NH4)2Cr2O7 and Na2Cr2O7 · 2H2O
Table 5. Crystal data and struc-
ture refinement for 3, 4 and 5.
Empirical formula
Formula weight
Temperature [K]
Wavelength [A]
Crystal system
Space group
K2CrSO4 (3)
274.26
295(2)
(NH4)2Cr2O7 (4) Na2Cr2O7·2H2O (5)
252.08
298.01
183(2)
173(2)
˚
0.71073
monoclinic
P21/n
a = 7.4024(1)
b = 7.3908(1)
c = 12.9883(2)
β = 90.021(1)
710.585(17)
4
0.71073
monoclinic
C2/c
0.71073
monoclinic
P21
˚
Unit cell dimensions [A, deg]
a = 13.2741(3)
b = 7.4831(2)
c = 7.7125(1)
β = 93.31
764.82(3)
4
a = 6.1216(1)
b = 10.7868(1)
c = 12.7175(1)
β = 95.080(1)
836.469(17)
4
3
˚
Volume [A ]
Z
Density (calculated) [g cm−3
]
2.56
3.1
536
2.19
2.37
Absorption coefficient [mm−1
F(000) [e]
]
2.8
504
2.7
584
Crystal size [mm3]
0.40×0.36×0.07 0.64×0.22×0.03 0.30×0.30×0.10
θ range for data collection [deg]
Index ranges
1.57 to 32.97
−11 ≤ h ≤ 10,
−11 ≤ k ≤ 10,
−19 ≤ l ≤ 19
10375
3.07 to 32.50
−19 ≤ h ≤ 19,
−11 ≤ k ≤ 11,
−11 ≤ l ≤ 11
6379
1.61 to 32.83
−9 ≤ h ≤ 8,
−16 ≤ k ≤ 16,
−19 ≤ l ≤ 19
14609
Reflections collected
Independent reflections/R(int)
Completeness to θ = 31.00◦ [%]
Absorption correction
Max. and min. transmission
Data / restraints / parameters
Goodness-of-fit on F2
2549/0.0755
99.6
multi-scan
0.814 and 0.374
2549/0/101
0.999
1341/0.0403
99.8
multi-scan
0.920 and 0.264
1341/10/65
1.003
5817/0.0446
100.0
multi-scan
0.773 and 0.496
5817/9/262
1.003
Final R indices [I ≥ 2σ(I)]
R1 = 0.0709,
wR2 = 0.2007
R1 = 0.0752,
wR2 = 0.2064
1.547/−1.173
–
R1 = 0.0286,
wR2 = 0.0732
R1 = 0.0386,
wR2 = 0.0786
0.393/−0.546
–
R1 = 0.0371,
wR2 = 0.0775
R1 = 0.0550,
wR2 = 0.0856
0.596/−0.662
−0.014(17)
0.0231(11)
R indices (all data)
−3
˚
Largest diff. peak and hole [e A
Absolute structure param.
Extinction coefficient
]
–
–
were corrected empirically for absorption and other effects to −0.014(17) on 2699 Friedel pairs for 5. Details on data
using SADABS [23]. The structures were solved by Direct collections and refinements are given in Table 5. Molecular
Methods and refined by full-matrix least-squares on all F2
graphics: DIAMOND [26].
data using SHELXTL [24]. The non-hydrogen atoms were re-
Further details of the crystal structures may be ob-
fined anisotropically. The hydrogen atoms in 4 and 5 were lo- tained from the Fachinformationszentrum Karlsruhe, 76344
cated from difference Fourier maps and refined isotropically Eggenstein-Leopoldshafen, Germany, on quoting the depos-
with restraints (common O–H distances and a common dis- itory number: CSD-417522 for 3, CSD-417523 for 4 and
placement parameter). The Flack parameter [25] was refined CSD-417524 for 5.
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