On crystal structure investigations of α- and β- ammoniumdithiocarbamate NH4CS2NH2 and the role of hydrogen bonding

Article abstract of DOI:10.1002/zaac.200900378

Single crystal X-ray data of the low temperature a- and the high temperature β-modifications of NH₄CS₂NH₂ were collected at 170(2) K and at 310(2) K, respectively and the crystal structures were investigated. The a-type crystallizes orthorhombically in the space group Pca2₁ with a = 8.2290(16), b = 5.6234(11), c = 10.694(2) A, and the β-type monoclinically in space group Cc with a = 14.7968(14), b = 9.4974(6), c = 9.3610(9) A and β = 129.119(9)°. The crystal chemical relations between the two modifications are discussed particularly with regard to the hydrogen-bonding networks.

Full text of DOI:10.1002/zaac.200900378

ARTICLE
DOI: 10.1002/zaac.200900378
On Crystal Structure Investigations of α- and β-Ammoniumdithiocarbamate
NH4CS2NH2 and the Role of Hydrogen Bonding
Christoph L. Teske[a] and Wolfgang Bensch*[a]
Dedicated to Professor Hans-Jörg Deiseroth on the Occasion of His 65th Birthday
Keywords: β-Modification; Carbamates; X-ray diffraction; Hydrogen bonds; Heats of transformation
Abstract. Single crystal X-ray data of the low temperature α- and the and the β-type monoclinically in space group Cc with a = 14.7968(14),
high temperature β-modifications of NH4CS2NH2 were collected at b = 9.4974(6), c = 9.3610(9) Å and β = 129.119(9)°. The crystal chem-
170(2) K and at 310(2) K, respectively and the crystal structures were ical relations between the two modifications are discussed particularly
investigated. The α-type crystallizes orthorhombically in the space with regard to the hydrogen-bonding networks.
group Pca21 with a = 8.2290(16), b = 5.6234(11), c = 10.694(2) Å,
by Desiraju [8]. In addition, hydrogen bonds to sulfur are of
Introduction
crucial importance in biological systems for example in human
The first detailed report on the interaction of carbon disulfide
retinoic acid nuclear receptor [9].
with alkali in alcohol dates from the year 1824 [1]. In his tract
We prepared crystals of both modifications (α and β) of am-
“Über die Wirkung zwischen Schwefelkohlenstoff und Ammo-
moniumdithiocarbamate and investigated the crystal structures
niak im Alkohol, mit…” Zeise reported on the formation of
especially regarding the role of hydrogen-bonding interactions
different sulfur compounds – using our modern nomenclature
and how they contribute to the systematic construction of the
it would be e.g. hydrogensulfide and ammoniumthiocyanate –
crystal packing. Furthermore, we provide complete sets of
leading him to the conclusion that in case of the reaction with
crystal data for further investigations.
ammonia, “a mutual decomposition of ammonia and carbon
disulfide is taking place”. In total, he distinguished four crys-
talline compounds precipitating from the solution, which he
investigated and described elaborately. One of them named by
him “das schwefelbrintige anthrazothionsaure Salz” [1, p. 179]
today is called ammoniumdithiocarbamate. Capacchi et al. [2]
investigated the crystal structure of α-ammoniumdithiocarbam-
ate, which is the stable modification at room temperature. Later
investigations deal with the thermal behavior and the formation
of the β-modification of NH4CS2NH2 [3–7], which is the meta-
stable form at room temperature. The high temperature form
(β) crystallizes monoclinically (pseudo rhombic) with β =
90.0(2)° (vide infra). Today, most facts about the simplest
Experimental Section
Preparation
As the preparation of NH4CS2NH2 was described repeatedly, we con-
fine ourselves here to mention three examples: [6, 10, 11]. Usually,
ethanol (96 %) or isopropylacetate are used as solvent for CS2, and
gaseous NH3 is introduced until saturation yielding about 45 to 96 %
of the crystalline solid depending on the proportion of water in the
solvent. In contrast to this synthetic procedure, we chose a compara-
tively crude but very simple method by applying chemicals customary
in trade to provide sufficient amounts of raw starting compounds.
starting composition in the great number of substituted dithio- CS2 (≈ 46 mL, 0.76 mol) was dissolved in ethanol (250 mL), and con-
centrated NH3 solution (100 mL, 25 %, ≈ 1.5 mol) was added with
stirring. The mixture was filled up with ethanol to about one liter.
Afterwards, the flask was closed and left shaded by aluminum foil
with stirring for one day and finally stored in the refrigerator below
–10 °C for one more day. After removal of the liquor, a colorless to
yellowish crystalline raw product remained, which was washed with
ligroin (b.p. 40–60 °C) and dried at room temperature with a final
yield of about 17 g (≈ 20 % based on the employed CS2). The yield
can be enhanced considerably by successively adding ligroin or other
non-polar solvents to the mother liquor. The raw product was stored
at about –18 °C. The yellowish discoloration of the raw product is
characteristic for an impurity as already noted earlier [3]. Interestingly,
we found a report [12] on yellow crystals with the composition
carbamates are known. Nevertheless, some structural aspects
are still worth to be investigated more in detail, i.e. the role of
hydrogen-bonding interactions in the two modifications. The
important role of N–H and O–H hydrogen bonds in the field
of weak interactions among molecules is pointed out notably
* Prof. Dr. W. Bensch
Fax: +49-431-880-1520
E-Mail: wbensch@ac.uni-kiel.de
[a] Institut für Anorganische Chemie
Christian-Albrechts-Universität Kiel
Max-Eyth-Str. 2
24118 Kiel, Germany
356
© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Z. Anorg. Allg. Chem. 2010, 636, 356–362

Ammoniumdithiocarbamate NH4CS2NH2 and the Role of Hydrogen Bonding
NH4HCS2O evidently isostructural [13] to α-NH4CS2NH2 with very N–H angle was assumed where the corresponding H–H distances are
similar lattice parameters. In this context, the yellow color of the raw 1.486 Å [18]. The atomic positions of H were refined applying these
product appears not unlikely to originate form that species.
values in the SHELXL-97 restraints [19] by the instructions e.g. DFIX
0.91 0.02 N2 H3 for the N–H bond lengths and DANG 1.486 0.04 H3
H4 for the α-structure. The corresponding values were applied for the
refinement of the β-structure, and fixed isotropic displacement parame-
ters [Uiso(H) = 1.5 Ueq(N)] were used. More technical details of the
data acquisition and some selected results of the refinements are sum-
marized in Table 1. The final atomic coordinates as well as the equiva-
lent isotropic displacement parameters are listed in Table 2. Table 3
shows a list of the shortest interatomic distances /Å and some selected
angles.
For each further investigation, we therefore re-crystallized a fresh
white sample from a saturated solution of the raw product in aqueous
concentrated NH3 by adding ethanol and ligroin (mixture 3:1).
The percent composition data were determined by combustion analysis
with a CHN-Rapid-Element-Analyzer (Heraeus GmbH) using sulfanil-
amide as standard: NH4CS2NH2 (110.20); N 25.14(9) (24.42); C
10.97(11) (10.90); H 5.57(9) (5.49); S 57.5(9) (58.19) % (average of
13 independent samples).
Table 1. Crystal data and structure refinement for NH4CS2NH2 (stand-
Crystals of β-NH4CS2NH2 were also grown from a saturated solution
of purified α-NH4CS2NH2 in aqueous concentrated NH3: At first, all
the solutions to be used were warmed up to 39 3 °C in a water bath.
A test tube with the saturated solution (about 1 mL) was kept in an
inclined position, and afterwards ethanol (about 3 mL) was added
without agitation. Finally, ligroin (about 0.5 mL) was added drop by
drop, which immediately caused a colorless cloud of microcrystals in
the upper part of the liquid column. The test tube was closed by a
rubber bug and the assembly stored inclined and kept at t ≈ 39 3 °C
until colorless transparent crystals of β-NH4CS2NH2, appropriate for
single-crystal X-ray investigations, had grown after four days.
ard deviations in parenthesis).
Crystal structure type
low temp.
high temp.
Empirical formula
Formula weight
Temperature /K
Wavelength /Å
Crystal system
Space group
a /Å
CH6N2S2
110.20
170(2)
310(2)
0.71073
orthorhombic
Pca21
monoclinic
Cc
8.2290(16)
5.6234(11)
10.694(2)
14.7968(14)
9.4974(6)
9.3610(9)
129.119(9)
1020.6(2)
8
b /Å
c /Å
β /°
Volume /Å3
494.9(2)
4
1.479
0.904
232
Thermal Investigations
Z
ρ (calcd.) /g·cm–3
1.434
μ /mm–1
0.877
Differential scanning calorimetry was performed with a DSC-204 de-
vice from NETZSCH (Selb) at heating (cooling) rates of 3 °C·min–1
in the range of T = –10 to 60 °C. The samples were placed in hermeti-
cally closed aluminum crucibles. X-ray powder patterns were collected
in the temperature range of 25 to 60 °C with a STOE Transmission
Diffractometer System STADI P (Cu-Kα1 λ = 1.54056 Å).
F(000)
464
Crystal size /mm
ϑ range /°
0.25 × 0.13 × 0.06 0.17 × 0.13 × 0.08
3.62 to 30.43
5312
2.78 to 28.03
7209
2464
0.0455
99.8
Reflections collected
Independent reflections
Rint
1457
0.0435
Completeness /%
Absorption correction
Max. /min. transmission
Refinement method
98.0
numerical
0.9215 / 0.7312
Single Crystal X-ray Investigations
0.9356 / 0.8667
Full-matrix least-squares on F2
The intensity data for the single-crystal X-ray investigations were col-
lected with a STOE Imaging Plate Diffraction System (IPDS-1) with
Data / restraints / parameters1457 / 11 / 60
2464 / 22 / 119
1.062
GOOF (F2)
R1 [I > 2σ(I)]
wR2
1.101
graphite monochromatized Mo-Kα radiation (λ
= 0.7107 Å) at
0.0261
0.0313
170(2) K for the α- and at 310(2) K for the β-modification. The raw
0.0693
0.0817
data were corrected for Lorentz and polarization effects, and an absorp- R1 (all data)
0.0270
0.0327
wR2 (all data)
Extinction coefficient
δF / e·Å–3
0.0696
0.0827
tion correction was applied using X-Red [14] and X-Shape [15]. The
structures were then solved by Direct Methods employing the
SHELXTL program package [16] performing the refinements against
F2. The α-NH4CS2NH2 modification crystallizes in the space group
Pca21 (No. 29) as reported earlier [2]. Indeed, the correct symmetry
for the crystal structure of β-NH4CS2NH2 is monoclinic, as already
supposed in [4]. An attempt to solve the structure of the β-modification
applying the pseudo-orthorhombic setting with a = 11.4846(8) Å, b =
9.4953(6) Å, c = 9.3607(9) Å and β = 90.0(2) ° in the space group Ia
showed reasonable results. However, we finally chose the standard
setting Cc (No. 9) as given in Table 1. A symmetry check using PLA-
TON [17] suggested no obvious additional symmetry. In the course of
the refinement of the crystal structure of β-NH4CS2NH2, it appeared
that the absolute structure could not be determined reliably. Hence, a
twin refinement for racemic twins was applied yielding 0.51(9) for the
BASF parameter. The non-hydrogen atoms were refined with aniso-
tropic displacement parameters. The hydrogen atoms of the amino
groups were positioned with idealized geometry and refined with fixed
bond lengths (N–H = 0.86 Å) and isotropic displacement parameters
0.103(12)
0.252 / –0.286
0.174(6)
0.305 /–0.321
Further details of the crystal structure investigations may be obtained
from the Fachinformationszentrum Karlsruhe 76344 Eggenstein-
Leopoldshafen, Germany on quoting the depository numbers CSD-
421191 for α-NH4CS2NH2 and CSD-421192 for β-NH4CS2NH2
(E-Mail: crysdata@fiz-karlsruhe.de).
Results and Discussion
The investigation of the thermal behavior of ammoniumdith-
iocarbamate has confirmed the former results published in lit-
erature [3, 6]. But we observed a significantly lower phase
transition temperature than that of 63 °C reported by Gattow
et al. [6]. We found by X-ray powder diffraction that the α → β
using a riding model. For the ammonium ions, an ideal tetrahedral H– phase transformation of NH4CS2NH2 occurs in the temperature
Z. Anorg. Allg. Chem. 2010, 356–362
© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
www.zaac.wiley-vch.de 357

C. L. Teske, W. Bensch
ARTICLE
Table 2. Atomic coordinates (× 104) and equivalent isotropic displace- Table 3. Selected bond lengths /Å and angles /° for NH4CS2NH2
ment parameters /Å2 × 103 for NH4CS2NH2 (lt = low temperature (standard deviations in parentheses, lt = low temperature structure, ht =
structure, ht = high temperature structure).·U(eq) is defined as one third high temperature structure).
of the trace of the orthogonalized Uij tensor. In the space group Pca21
lt
(No. 29) the atoms occupy the position (4e) 1 and in the space group
Cc (No. 9) the position (4a) 1, respectively (standard deviations in
S1–C
S2–C
N1–C
1.723 (2)
1.726 (2)
1.331 (2)
3.962 (2)
3.429 (2)
3.325 (2)
3.377 (2)
3.361 (2)
3.298 (2)
3.556 (2)
3.522 (2)
3.479 (2)
119.5 (1)
118.6 (1)
121.9 (1)
parentheses).
lt – NH4CS2NH2
(ii)
N2–S1(iii)
x
y
z
U(eq)
N2–S1(iv)
S1
S2
N1
N2
C
9437(1)
9956(1)
8179(2)
2287(2)
9118(2)
4661(1)
1079(1)
4958(3)
284(2)
3690(3)
561(1) 15(1)
2620(1) 14(1)
2833(2) 24(1)
N2–S1(v)
N2–S1(vi)
N2–S2(iii)
147(1)
2070(1) 13(1)
15(1)
N2–S2(vii)
N2–S2(iv)
Calculated hydrogen positions, atomic coordinates (× 103)
N2–S2
x
y
z
(mean) N2–S
N(1)–C(1)–S(1)
N(1)–C(1)–S(2)
S(1)–C(1)–S(2)
H1
H2
H3
H4
H5
H6
773
628
257
801
447
361
293(2)
284(2)
159(3)
174(3)
–103(3)
167(2)
33(4)
15(4)
21(2)
17(2)
81(2)
–59(2)
Symmetry codes: (ii) –1+x, –1+y, z; (iii) –1+x, y, z; (iv) –0.5+x, –y,
z; (v) –0.5+x, 1–y, z; (vi) 1–x, –y, –0.5+z; (vii) 1.5–x, y, –0.5+z.
ht
ht – NH4CS2NH2
S1–C1
S2–C1
S3–C2
S4–C2
N1–C1
N2–C2
1.709(2)
1.705(2)
1.705(2)
1.706(2)
1.326(3)
1.321(3)
3.369(2)
3.345(2)
3.470(3)
3.431(2)
3.463(2)
3.769(3)
3.525(2)
3.594(3)
3.496(2)
3.627(2)
3.746(2)
3.441(2)
3.355(3)
3.718(3)
3.510(3)
3.406(3)
3.537(3)
3.543(2)
119.1(2)
117.7(2)
123.2(1)
118.3(2)
118.3(2)
123.4(1)
x
y
z
U(eq)
S1
S2
S3
S4
N1
N2
N3
N4
C1
C2
7783(1)
5973(1)
5810(1)
4094(1)
5549(2)
6312(2)
3876(2)
8014(2)
6369(2)
5469(2)
2069(1)
4341(1)
1779(1)
2276(1)
1674(2)
1801(4)
4507(2)
4583(3)
2629(2)
1950(2)
8879(1) 40(1)
7296(1) 38(1)
429(1) 41(1)
1085(1) 49(1)
6377(3) 45(1)
3642(3) 63(1)
7870(3) 45(1)
2013(3) 47(1)
7434(2) 28(1)
1853(3) 32(1)
(v)
N3–S1(vi)
N3–S1
N3–S2(vii)
N3–S2(viii)
N3–S3(ix)
N3–S3(viii)
N3–S4(vii)
N3–S4
Calculated hydrogen positions, atomic coordinates (× 103)
x
y
z
H1
H2
H3
H4
H5
H6
H7
H8
H9
H10
H11
H12
483
192
564
(mean) N3–S
574
81
643
(x)
N4–S1(xi)
701
162
406
N4–S1(x)
616
188
439
N4–S2(xii)
438(3)
320(2)
382(4)
423(3)
756(3)
820(3)
872(2)
764(3)
385(3)
417(4)
517(4)
505(4)
454(4)
545(2)
419(4)
398(3)
869(5)
691(4)
851(5)
753(5)
234(5)
186(5)
287(4)
105(4)
N4–S2
N4–S3(xiii)
N4–S3(xiv)
N4–S4(xiii)
N4–S4
(mean) N4–S
N(1)–C(1)–S(2)
N(1)–C(1)–S(1)
S(2)–C(1)–S(1)
N(2)–C(2)–S(3)
N(2)–C(2)–S(4)
S(3)–C(2)–S(4)
range of 30 to 35 °C (Figure 1). The DSC data revealed a
transition temperature Tonset = 31.9(4) °C and the heat of trans-
formation could be estimated as R = +5.21(3) kJ·mol–1. Cool-
ing the sample down, the α-form is formed at about 0 °C, i.e.
the reversible transformation is slightly kinetically hindered.
We performed cycling experiments heating and cooling a sam-
ple four times. The estimated heat of transformation remains
constant. Decomposition of the compound starts at about
80 °C. The preparation of crystals of β-NH4CS2NH2 was suc-
Symmetry codes: (v) –0.5+x, 0.5+y, z; (vi) –0.5+x, 0.5–y, –0.5+z;
(vii) x, 1–y, 0.5+z; (viii) x, y, 1+z; (ix) –0.5+x, 0.5–y, 0.5+z; (x) x,
y, –1+z; (xi) x, 1–y, –0.5+z; (xii) x, 1–y, –0.5+z; (xiii) 0.5+x, 0.5–y,
0.5+z; (xiv) 0.5+x, 0
The crystal structure of the two polymorphic ammoniumdith-
–
cessful slightly above 35 °C (vide supra). The phase transition iocarbamates consists of planar CS2NH2 anions linked by the
+
is reversible (enantiotropic) and the two phases coexist in a tetrahedral NH4 cations. Both crystal structures (α and β) dif-
narrow temperature range. Therefore one can assume that the fer fundamentally from each other in the arrangement and
transition is of second order.
alignment of these ions.
358 www.zaac.wiley-vch.de
© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Z. Anorg. Allg. Chem. 2010, 356–362

Ammoniumdithiocarbamate NH4CS2NH2 and the Role of Hydrogen Bonding
bamate anions are joined by a medium strong N(1)–H(1)···S(2)
(H···S = 2.72 Å) [24] bond leading to a chain-like arrangement
propagating along [100]. The chains are then cross-linked by
bifurcated N(1)–H(2)···S(1) bonds (Table 4 and Figure 3)
forming undulated layers stacked along [010] (Figure 4). The
latter H···S distances of 2.91 and 3.00 Å indicate very weak
hydrogen-bonding interactions as they are very close to or
equal the sum of the estimated van der Waals radii (Σ = 3.0 Å,
+
[25]). The NH4 cations residing between these anionic layers
accomplish the coherence in the direction [010] (Figure 5) by
means of four very strong hydrogen bonds (H···S = 2.40 to
2.48 Å, Table 4). Taking into account only the shortest N···S
+
separations, the NH4 cation is surrounded by the four sulfur
atoms forming a slightly distorted tetrahedron. The tetrahedra
share common corners yielding chains directed along [001]
(Figure 5). Along the chains the tetrahedra point alternating to
the left and right side.
On the other hand, straight chains are observed running par-
allel to [010]. Neighbored chains are joined by the two sulfur
Figure 1. X-ray powder pattern in the range of 15° < 2ϑ < 60° for α-
NH4CS2NH2 (top, registered at T ≈ 25 °C and for β-NH4CS2NH2 (bot-
tom, registered at T ≈ 35 °C).
+
In the structure of the α-modification, the NH4 cation is
surrounded by eight sulfur atoms belonging to six different
–
CS2NH2 anions with four short H···S distances (2.40–2.48 Å)
pointing more or less into the direction of the N–H bonds
(mean N···S = 3.34 Å, Table 3, mean angle N–H···S ≈ 172°,
Table 4 and Figure 2). We note that such short H···S separa-
tions were also observed in a number of organic ammoniumtet-
rathiomolybdates and tetrathiotungstates [20–23]. Three fur-
ther S···H separations with longer S···H distances (2.72–
3.00 Å, average N···S = 3.52 Å, N–H···S between 119 and
144°) indicate less strong bonding interactions. Finally, N(2)
has a S(1) atom at a long distance of 3.962 Å completing the
eightfold environment. Counting only the seven shortest N···S
distances an average N···S separation of 3.41 Å is obtained
(including the long distance: 3.479 Å). Closer examination of
the hydrogen bonding pattern leads to a deeper insight into the
arrangement and packing of the building blocks. The thiocar-
Figure 3. The layered arrangement of the thiocarbamate anions in α-
NH4CS2NH2. (H···S bonds dashed lines, the NH4+ tetrahedra are omit-
ted for better clarity). The outlines of unit cell are indicated.
Figure 2. Coordination sphere around N2 in α-NH4CS2NH2 showing
Figure 4. Connection of the undulated layers containing the anions by
+
the four shortest N–H···S interactions. H···S bonds dashed lines. The the NH4 cations yielding
a three-dimensional network of α-
indices in brackets refer to the symmetry codes (Table 4). We note NH4CS2NH2. The outlines of unit cell are indicated (H···S bonds
+
that there are four additional N–S distances, which are significantly dashed lines, N2 positions of the NH4 tetrahedra marked only inside
longer (Table 3).
the unit cell).
Z. Anorg. Allg. Chem. 2010, 356–362
© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
www.zaac.wiley-vch.de
359

C. L. Teske, W. Bensch
ARTICLE
Table 4. Hydrogen bonds with H···A < r(A) + 2.000 Å and D–H···A > 110° (standard deviations in parenthesis).
α-modification
D–H···A
D–H
H···A
D···A
D–H···A
(viii)
N1–H1···S2(ix)
N1–H2···S1(x)
N1–H2···S1(iii)
N2–H5···S2(iv)
N2–H3···S1(vi)
N2–H6···S2(v)
N2–H4···S1
0.88
2.72
3.472(2)
3.629(2)
3.522(2)
3.298(2)
3.325(2)
3.361(2)
3.377(2)
144
0.88
2.91
141
0.88
3.00
119
0.91(2)
0.91(2)
0.91(2)
0.90(2)
2.40(2)
2.42(2)
2.47(2)
2.48(2)
175(2)
173(2)
167(2)
172(2)
Symmetry codes: (iii) –1+x, y, z; (iv) –0.5+x, –y, z; (v) –0.5+x, 1–y, z; (vi) 1–x, –y, –0.5+z; (viii) x–0.5, –y+1, z; (ix) –x+1.5, y, z+0.5; (x) –
x+2, –y+1, z+0.5.
ꢀ-modification
D–H···A
D–H
H···A
D···A
D–H···A
(ii)
N1–H1···S1
0.86
2.55
3.400(3)
3.483(2)
3.326(3)
3.391(4)
3.370(3)
3.463(2)
3.345(2)
3.470(4)
3.594(2)
3.406(3)
3.354(4)
3.511(3)
3.441(2)
3.628(3)
170
N1–H2···S3(iii)
N2–H3···S4 (iv)
N2–H4···N1
0.86
2.66
161
0.86
0.86
2.61
2.54
141
169
(v)
N3–H7···S1(viii)
0.91(5)
0.91(4)
0.88(3)
0.92(5)
0.92(5)
0.91(3)
0.90(5)
0.91(3)
0.90(3)
0.90(3)
2.53(5)
2.57(4)
2.76(3)
2.80(5)
2.83(4)
2.55(4)
2.56(5)
2.60(3)
2.76(3)
2.83(4)
154(4)
168(3)
125(3)
130(3)
142(4)
158(4)
149(3)
176(3)
133(2)
148(4)
N3–H5···S3(vi)
N3–H6···S1
N3–H8···S2(vii)
N3–H8···S4
(xiv)
N4–H10···S4
N4–H9···S2(xii)
(xiii)
N4–H11···S3(x)
N4–H12···S2(x)
N4–H12···S1
Symmetry codes: (ii) –0.5+x, 0.5–y, –0.5+z; (iii) 0.5+x, 1.5–y, 0.5+z; (iv) x, 1–y, 0.5+z; (v) –0.5+x, 0.5+y, z; (vi) –0.5+x, 0.5–y, –0.5+z; (vii)
x, 1– y, 0.5+z; (viii) x, y, 1+z; (ix) –0.5+x, 0.5–y, 0.5+z; (x) x, y, –1+z; (xi) x, 1–y, –0.5+z; (xii) x, 1–y, –0.5+z; (xiii) 0.5+x, 0.5–y, 0.5+z;
(xiv) 0.5+x, 0.5+y, z.
Figure 5. Connection of the NH4+ centered tetrahedra in the α-modifi-
cation of NH4CS2NH2.
Figure 6. The three-dimensional network in the structure of the α-
+
form formed by corner-sharing of the NH4 centered tetrahedra.
atoms of the thiocarbamate anion yielding finally a three-di- between the anions does not occur exclusively by N–H···S
mensional network (Figure 6). bonds but also by one N–H···N bond. The anions of C1-type
In the ꢀ-type crystal structure, the assembly of the different are linked by N(1)–H(1)···S(1) and those of the C2-type by
components differs fundamentally. First of all, there are two N(2)–H(3)···S(4) (Table 4). Both anions form chains propaga-
+
–
crystallographically unique NH4 cations and CS2NH2 units ting along [101] (Figure 7), which are distorted against each
(marked N3, N4, C1 and C2 in Figure 7). In contrast to the other with an angle between the planes through the constituting
hydrogen bonding pattern in the α-modification, the linkage atoms S, C, N, τ = 77.0(1) °. A further medium strong hydro-
360
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Z. Anorg. Allg. Chem. 2010, 356–362

Ammoniumdithiocarbamate NH4CS2NH2 and the Role of Hydrogen Bonding
gen bond N(1)–H(2)···S(3) (Table 4) connects these chains ammonium tetrahedra, which are surrounded by eight sulfur
along [010] (Figure 7 right §) forming a two-dimensional net- atoms (Figure 8). These sulfur atoms belong to seven different
work stacked along [001]. The new feature compared to the α- dithiocarbamate molecules whereas in the α-modification the
+
form represents the N(2)–H(4)···N(1) bond (Figure 7 left * and NH4 cation has eight sulfur atoms belonging to six dithiocar-
Figure 8 right *) between the anions cross-linking the network bamate anions.
and thus completing the three-dimensional framework (Fig-
+
ure 8). The two NH4 cations [N(3) and N(4)] each have five
S···H contacts to five different anions (Figure 9a and Fig-
ure 9b, Table 4). Considering the relatively long S(2)···H(7)
separation of about 2.96 Å (angle N(3)–H(7)···S(2): 115.3°)
the coordination number of N(3) is six. We note that the short-
est S···H bonds in the ꢀ-form are significantly longer than
those in the α-modification (see Table 4). The hydrogen bond-
ing pattern generates channels running along [010] hosting the
Figure 7. Connection of the anions in the ꢀ-form by S···H and N···H
bonds. The outlines of the unit cell are indicated (H···S and H···N
+
bonds dashed lines, N3 and N4 positions of the NH4 tetrahedra lo-
cated in the channels of the three-dimensional network). C1 and C2
–
indicate the two crystallographic different CS2NH2 units (meaning of
§ and * see text).
Figure 9. Coordination sphere around the two crystallographic inde-
pendent NH4+ cations N3 (a) and N4 (b) in ꢀ-NH4CS2NH2. H···S bonds
dashed lines. The indices in brackets refer to the symmetry codes (Ta-
ble 4).
The C–S bonds in the ꢀ-form are shorter than in the α-modi-
fication (Table 3), which is not caused by a stronger vibration
of the sulfur atoms. A correction for libration effects elongates
the C–S bonds only slightly by about 0.002 Å.
Conclusions
The crystal structure investigations of the two modifications
of NH4CS2NH2 particularly regarding the hydrogen bonding
patterns have provided a better understanding of the structural
Figure 8. The NH4+ cations located in the channels of the three-dimen-
peculiarities and different arrangements of the anions and cati-
sional network in the structure of the ꢀ-modification. The outlines of
ons. The comparison of the two crystal structures with respect
unit cell are indicated (H···S and H···N bonds dashed lines, N3 and N4
+
to the number, strengths and type of the hydrogen bonds dem-
onstrates that there is a stronger interaction between the
positions of the NH4 tetrahedra located in the channels of the three-
dimensional network, meaning of * see text).
Z. Anorg. Allg. Chem. 2010, 356–362
© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
www.zaac.wiley-vch.de
361

C. L. Teske, W. Bensch
ARTICLE
–
[7] G. Gattow, V. Hahnkamm, Z. Anorg. Allg. Chem. 1969, 365, 70–
78.
CS2NH2 anions in the ꢀ-form than in the α-modification. On
the other hand, a stronger interaction of the NH4 cations with
the framework formed by hydrogen bonding interactions be-
tween the anions is observed. This elucidates where the gain
of lattice energy is consumed, while the high temperature
+
[8] G. R. Desiraju,T. Steiner, The Weak Hydrogen Bond in Structural
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ammonium ions and the anionic framework has become
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Received: August 7, 2009
Published Online: December 17, 2009
176.
362
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© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Z. Anorg. Allg. Chem. 2010, 356–362