N,N-Dimethyl­guanidinium chloride

The title salt, [(CH₃)₂NC(NH₂)₂]⁺·Cl⁻ or C₃H₁₀N₃⁺·Cl⁻, is the first crystallographically characterized example of a dialkyl­guanidinium halide, [R₂NC(NH₂)₂]⁺·X⁻. The essentially planar dimethyl­guanidinium cations are packed in a parallel alignment. Because of the delocalization of N electron lone pairs within the CN₃ unit, the core C[pdbond]N bonds [1.332 (3) Å] are significantly shorter than the terminal N—CH₃ bonds [1.461 (2) Å]. Chloride anions are fourfold coordinated by amine H atoms. Both ions are located on special positions, the dimethyl­guanidinium cation on the twofold axis along [010] and the Cl⁻ anion on the twofold axis along [001].

Key indicators

• Single-crystal X-ray study
• T = 100 K
• Mean [sigma](N-C) = 0.002 Å
• R factor = 0.035
• wR factor = 0.084
• Data-to-parameter ratio = 11.9

checkCIF/PLATON results

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Alert level C
PLAT764_ALERT_4_C Overcomplete CIF Bond List Detected (Rep/Expd) .       1.25 Ratio

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   1 ALERT level C = Check and explain
   0 ALERT level G = General alerts; check

   0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   0 ALERT type 2 Indicator that the structure model may be wrong or deficient
   0 ALERT type 3 Indicator that the structure quality may be low
   1 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

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Computing details

Data collection: SMART32 (Bruker, 2000); cell refinement: SAINT32 (Bruker, 2000); data reduction: SAINT32; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ATOMS (Dowty, 2005); software used to prepare material for publication: SHELXL97.

N,N-Dimethylguanidinium chloride

Crystal data

C3H10N3^+·Cl^−	F(000) = 1056
Mr = 123.59	Dx = 1.322 Mg m^−3
Orthorhombic, Fddd	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -F 2uv 2vw	Cell parameters from 1580 reflections
a = 6.7568 (9) Å	θ = 3.1–26.3°
b = 15.732 (2) Å	µ = 0.50 mm^−1
c = 23.364 (3) Å	T = 100 K
V = 2483.5 (6) Å^3	Needle, colourless
Z = 16	0.40 × 0.05 × 0.05 mm

Data collection

Bruker SMART APEX diffractometer	643 independent reflections
Radiation source: fine-focus sealed tube	550 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.033
ω scans	θmax = 26.3°, θmin = 3.1°
Absorption correction: multi-scan (SADABS; Sheldrick, 2004)	h = −8→8
Tmin = 0.825, Tmax = 0.975	k = −18→19
4602 measured reflections	l = −28→28

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.035	Hydrogen site location: difference Fourier map
wR(F^2) = 0.085	All H-atom parameters refined
S = 1.17	w = 1/[σ^2(Fo^2) + (0.0415P)^2 + 3.1788P] where P = (Fo^2 + 2Fc^2)/3
643 reflections	(Δ/σ)max < 0.001
54 parameters	Δρmax = 0.29 e Å^−3
0 restraints	Δρmin = −0.15 e Å^−3

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

	x	y	z	Uiso*/Ueq
Cl1	0.1250	0.6250	0.20937 (2)	0.0218 (2)
N1	0.6250	0.80005 (13)	0.1250	0.0201 (5)
C1	0.6250	0.88474 (16)	0.1250	0.0185 (5)
N2	0.6096 (3)	0.92760 (11)	0.07604 (7)	0.0228 (4)
H1	0.623 (3)	0.9785 (16)	0.0770 (9)	0.024 (6)*
H2	0.556 (4)	0.9056 (16)	0.0468 (11)	0.037 (7)*
C2	0.6069 (3)	0.75018 (13)	0.17749 (9)	0.0258 (5)
H3	0.728 (4)	0.7277 (14)	0.1870 (9)	0.030 (6)*
H4	0.557 (4)	0.7847 (18)	0.2067 (11)	0.045 (7)*
H5	0.513 (4)	0.7071 (16)	0.1706 (10)	0.037 (6)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cl1	0.0300 (4)	0.0169 (3)	0.0184 (3)	−0.0005 (3)	0.000	0.000
N1	0.0260 (11)	0.0171 (11)	0.0171 (10)	0.000	0.0014 (9)	0.000
C1	0.0138 (11)	0.0208 (12)	0.0210 (12)	0.000	−0.0006 (10)	0.000
N2	0.0296 (9)	0.0154 (9)	0.0233 (9)	−0.0029 (7)	−0.0050 (8)	0.0019 (6)
C2	0.0315 (12)	0.0200 (10)	0.0260 (10)	−0.0026 (9)	−0.0005 (9)	0.0048 (8)

Geometric parameters (Å, º)

N1—C1	1.332 (3)	N2—H1	0.81 (2)
N1—C2	1.461 (2)	N2—H2	0.85 (3)
N1—C2^i	1.461 (2)	C2—H3	0.92 (2)
C1—N2^i	1.332 (2)	C2—H4	0.94 (3)
C1—N2	1.332 (2)	C2—H5	0.94 (3)
C1—N1—C2	122.48 (11)	H1—N2—H2	119 (2)
C1—N1—C2^i	122.48 (11)	N1—C2—H3	109.6 (14)
C2—N1—C2^i	115.0 (2)	N1—C2—H4	109.4 (16)
N2^i—C1—N2	119.2 (2)	H3—C2—H4	112 (2)
N2^i—C1—N1	120.41 (12)	N1—C2—H5	107.4 (14)
N2—C1—N1	120.41 (12)	H3—C2—H5	111 (2)
C1—N2—H1	118.0 (15)	H4—C2—H5	107 (2)
C1—N2—H2	121.2 (17)

Symmetry code: (i) −x+5/4, y, −z+1/4.