dl-Alaninium iodide.

The crystal structure of dl-alanine hydro-iodide (1-carb-oxy-ethanaminium iodide), C(3)H(8)NO(2) (+)·I(-), is that of an organic salt consisting of N-protonated cations and iodide anions. The compound features homochiral helices of N-H⋯O hydrogen-bonded cations in the [010] direction; neighbouring chains are related by crystallographic inversion centers and hence show opposite chirality. The iodide counter-anions act as hydrogen-bond acceptors towards H atoms of the ammonium and carb-oxy groups, and cross-link the chains along [100]. Thus, an overall two-dimensional network is formed in the ab plane. No short contacts occur between iodide anions.

Related literature

For related structures of l-alanine hydro­chloride, see: Di Blasio et al. (1977 ▶), d-alanine alaninium bromide, see: Fischer (2006 ▶), l-alanine hydro­chloride monohydrate, see: Yamada et al. (2008 ▶) and dl-alanine hydro­chloride, see: Trotter (1962 ▶).

Experimental

Crystal data

C3H8NO2 +·I−

M = 217.00

Monoclinic,

a = 7.6975 (11) Å

b = 5.7776 (8) Å

c = 16.034 (2) Å

β = 98.999 (2)°

V = 704.30 (17) Å3

Z = 4

Mo Kα radiation

μ = 4.46 mm−1

T = 100 K

0.30 × 0.11 × 0.05 mm

Data collection

Bruker D8 goniometer with SMART APEX CCD detector

Absorption correction: multi-scan (SADABS; Bruker, 2001 ▶) T min = 0.348, T max = 0.808

10196 measured reflections

2109 independent reflections

1887 reflections with I > 2σ(I)

R int = 0.055

Refinement

R[F 2 > 2σ(F 2)] = 0.026

wR(F 2) = 0.062

S = 1.05

2109 reflections

77 parameters

3 restraints

H atoms treated by a mixture of independent and constrained refinement

Δρmax = 1.17 e Å−3

Δρmin = −1.87 e Å−3

Data collection: SMART (Bruker, 2001 ▶); cell refinement: SAINT (Bruker, 2001 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: PLATON (Spek, 2009 ▶); software used to prepare material for publication: publCIF (Westrip, 2010 ▶).

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S1600536812022003/nk2163sup1.cif

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536812022003/nk2163Isup2.hkl

Supplementary material file. DOI: 10.1107/S1600536812022003/nk2163Isup3.cml

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

C3H8NO2+·I−	F(000) = 408
Mr = 217.00	Dx = 2.047 Mg m−3
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yn	Cell parameters from 3131 reflections
a = 7.6975 (11) Å	θ = 2.6–30.3°
b = 5.7776 (8) Å	µ = 4.46 mm−1
c = 16.034 (2) Å	T = 100 K
β = 98.999 (2)°	Needle, colourless
V = 704.30 (17) Å3	0.30 × 0.11 × 0.05 mm
Z = 4

Bruker D8 goniometer with SMART APEX CCD detector diffractometer	2109 independent reflections
Radiation source: INCOATEC microsource	1887 reflections with I > 2σ(I)
Multilayer optics monochromator	Rint = 0.055
ω scans	θmax = 30.7°, θmin = 2.6°
Absorption correction: multi-scan (SADABS; Bruker, 2001)	h = −10→11
Tmin = 0.348, Tmax = 0.808	k = −8→8
10196 measured reflections	l = −22→22

Refinement on F2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.026	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.062	H atoms treated by a mixture of independent and constrained refinement
S = 1.05	w = 1/[σ2(Fo2) + (0.020P)2 + 0.4P] where P = (Fo2 + 2Fc2)/3
2109 reflections	(Δ/σ)max = 0.001
77 parameters	Δρmax = 1.17 e Å−3
3 restraints	Δρmin = −1.87 e Å−3

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.

	x	y	z	Uiso*/Ueq
I1	0.78595 (2)	0.38517 (3)	0.868059 (10)	0.01622 (7)
O1	0.4337 (3)	0.6529 (4)	0.92827 (13)	0.0248 (5)
H1	0.508 (5)	0.577 (6)	0.913 (2)	0.030*
O2	0.2836 (3)	0.6020 (3)	0.79725 (13)	0.0193 (4)
C1	0.3013 (3)	0.6870 (5)	0.86701 (16)	0.0162 (5)
C2	0.1684 (3)	0.8526 (5)	0.89481 (17)	0.0158 (5)
H2	0.1169	0.7800	0.9420	0.019*
C3	0.2528 (4)	1.0818 (5)	0.9252 (2)	0.0249 (6)
H3A	0.1619	1.1888	0.9380	0.030*
H3B	0.3120	1.1483	0.8809	0.030*
H3C	0.3390	1.0558	0.9761	0.030*
N1	0.0254 (3)	0.8877 (4)	0.82138 (14)	0.0143 (4)
H1A	0.060 (4)	0.928 (5)	0.7744 (16)	0.017*
H1B	−0.052 (4)	0.988 (5)	0.834 (2)	0.017*
H1C	−0.036 (4)	0.761 (4)	0.811 (2)	0.017*

	U11	U22	U33	U12	U13	U23
I1	0.01442 (11)	0.01740 (11)	0.01628 (10)	0.00331 (6)	0.00066 (7)	0.00025 (6)
O1	0.0196 (10)	0.0337 (12)	0.0190 (10)	0.0129 (9)	−0.0036 (8)	−0.0060 (9)
O2	0.0183 (10)	0.0227 (11)	0.0159 (9)	0.0043 (7)	0.0000 (8)	−0.0040 (7)
C1	0.0153 (12)	0.0167 (13)	0.0164 (12)	0.0011 (9)	0.0021 (9)	0.0011 (9)
C2	0.0146 (12)	0.0185 (13)	0.0136 (11)	0.0032 (9)	−0.0005 (9)	−0.0007 (9)
C3	0.0220 (14)	0.0223 (14)	0.0272 (15)	0.0040 (11)	−0.0059 (12)	−0.0102 (12)
N1	0.0146 (11)	0.0154 (11)	0.0119 (10)	0.0010 (8)	−0.0006 (8)	0.0005 (8)

O1—C1	1.315 (3)	C3—H3A	0.98
O1—H1	0.79 (4)	C3—H3B	0.98
O2—C1	1.210 (3)	C3—H3C	0.98
C1—C2	1.517 (4)	N1—H1A	0.87 (2)
C2—N1	1.495 (3)	N1—H1B	0.88 (2)
C2—C3	1.521 (4)	N1—H1C	0.87 (2)
C2—H2	1.00
C1—O1—H1	111 (3)	C2—C3—H3B	109.5
O2—C1—O1	126.3 (3)	H3A—C3—H3B	109.5
O2—C1—C2	123.0 (2)	C2—C3—H3C	109.5
O1—C1—C2	110.8 (2)	H3A—C3—H3C	109.5
N1—C2—C1	107.5 (2)	H3B—C3—H3C	109.5
N1—C2—C3	111.1 (2)	C2—N1—H1A	115 (2)
C1—C2—C3	111.7 (2)	C2—N1—H1B	110 (2)
N1—C2—H2	108.8	H1A—N1—H1B	110 (3)
C1—C2—H2	108.8	C2—N1—H1C	110 (2)
C3—C2—H2	108.8	H1A—N1—H1C	107 (3)
C2—C3—H3A	109.5	H1B—N1—H1C	103 (3)

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1···I1	0.79 (4)	2.61 (4)	3.391 (2)	171 (3)
N1—H1A···O2i	0.87 (3)	2.05 (3)	2.861 (3)	155 (3)
N1—H1B···I1ii	0.88 (3)	2.71 (3)	3.557 (2)	163 (3)
N1—H1C···I1iii	0.87 (3)	2.80 (3)	3.580 (2)	150 (3)

Table 1

Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O1—H1⋯I1	0.79 (4)	2.61 (4)	3.391 (2)	171 (3)
N1—H1A⋯O2i	0.87 (3)	2.05 (3)	2.861 (3)	155 (3)
N1—H1B⋯I1ii	0.88 (3)	2.71 (3)	3.557 (2)	163 (3)
N1—H1C⋯I1iii	0.87 (3)	2.80 (3)	3.580 (2)	150 (3)

Symmetry codes: (i) ; (ii) ; (iii) .