The hydro­gen-bonding network in rac-ammonium trans-2-carboxy­cyclo­hexane­carboxyl­ate

The title salt, NH₄⁺·C₈H₁₁O₄^-, contains tetrahedrally coordin­ated ammonium ions and monodeprotonated anions of rac-trans-1,2-cyclo­hexane­di­carboxyl­ic acid. In the anions, carboxyl­ic acid and carboxyl­ate fragments are identified by their clearly differentiated C-O bond distances. The cations and anions form columns along the b axis, which are arranged in the crystal structure to give tilted, alternating hydro­phobic (back-to-back cyclo­hexyl) and hydro­philic (ammonium, carboxyl­ate and carboxyl­ic acid) layers stacked along the a direction. The ammonium ion utilizes each of its four H atoms to form five hydrogen bonds with the negatively charged carboxyl­ate O atoms. A hydrogen bond between a carboxyl­ate O atom and the hydroxyl group of the carboxyl­ic acid fragment completes an extensive interionic hydrogen-bonding network.

Key indicators

• Single-crystal X-ray study
• T = 297 K
• Mean [sigma](C-C) = 0.004 Å
• R factor = 0.054
• wR factor = 0.154
• Data-to-parameter ratio = 9.7

checkCIF/PLATON results

No syntax errors found



Alert level B
ABSTM02_ALERT_3_B  The ratio of expected to reported Tmax/Tmin(RR') is < 0.75
            Tmin and Tmax reported:      0.678     1.000
            Tmin' and Tmax expected:      0.947     0.998
            RR' =      0.714
            Please check that your absorption correction is appropriate.
PLAT061_ALERT_3_B Tmax/Tmin Range Test RR' too Large .............       0.71

Alert level C
PLAT088_ALERT_3_C Poor Data / Parameter Ratio ....................       9.72
PLAT242_ALERT_2_C Check Low    U(eq) as Compared to Neighbors ....         C7

   0 ALERT level A = In general: serious problem
   2 ALERT level B = Potentially serious problem
   2 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
   1 ALERT type 2 Indicator that the structure model may be wrong or deficient
   3 ALERT type 3 Indicator that the structure quality may be low
   0 ALERT type 4 Improvement, methodology, query or suggestion

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Computing details

Data collection: SMART (Bruker, 2000); cell refinement: SMART; data reduction: SAINT (Bruker, 2000); program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEPIII (Burnett & Johnson, 1996) and ORTEP-32 (Farrugia, 1997); software used to prepare material for publication: SHELXTL (Bruker, 2000).

rac-ammonium trans-2-carboxycyclohexanecarboxylate

Crystal data

NH4^+·C8H11O4^−	F(000) = 408
Mr = 189.21	Dx = 1.295 Mg m^−3
Monoclinic, P21/c	Melting point: 493 K K
Hall symbol: -P 2ybc	Mo Kα radiation, λ = 0.71073 Å
a = 15.712 (7) Å	Cell parameters from 710 reflections
b = 6.141 (3) Å	θ = 2.7–21.4°
c = 10.464 (5) Å	µ = 0.10 mm^−1
β = 104.96 (4)°	T = 297 K
V = 975.5 (8) Å^3	Plate, colorless
Z = 4	0.52 × 0.28 × 0.02 mm

Data collection

Bruker SMART CCD area-detector diffractometer	1731 independent reflections
Radiation source: fine-focus sealed tube	1155 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.058
φ and ω scans	θmax = 25.1°, θmin = 2.7°
Absorption correction: multi-scan (SADABS, Blessing, 1995)	h = −18→18
Tmin = 0.678, Tmax = 1.00	k = −7→7
6692 measured reflections	l = −11→12

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)] = 0.054	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.154	All H-atom parameters refined
S = 1.00	w = 1/[σ^2(Fo^2) + (0.0903P)^2] where P = (Fo^2 + 2Fc^2)/3
1731 reflections	(Δ/σ)max < 0.001
178 parameters	Δρmax = 0.23 e Å^−3
0 restraints	Δρmin = −0.18 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.

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.

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

	x	y	z	Uiso*/Ueq
O1	0.36646 (13)	0.4072 (4)	0.8366 (2)	0.0871 (8)
O2	0.26140 (12)	0.1685 (3)	0.76074 (18)	0.0679 (6)
O3	0.40577 (11)	0.8115 (3)	1.04577 (18)	0.0668 (6)
O4	0.36775 (10)	0.5274 (3)	1.14467 (15)	0.0560 (5)
N	0.50664 (17)	0.8000 (5)	0.8588 (2)	0.0496 (6)
C1	0.23173 (14)	0.4412 (4)	0.9014 (2)	0.0456 (6)
C2	0.26233 (14)	0.6663 (4)	0.9544 (2)	0.0450 (6)
C3	0.19661 (17)	0.7735 (5)	1.0198 (3)	0.0576 (7)
C4	0.1036 (2)	0.7731 (7)	0.9319 (4)	0.0818 (10)
C5	0.0747 (2)	0.5473 (7)	0.8875 (4)	0.0818 (11)
C6	0.13675 (17)	0.4425 (7)	0.8155 (3)	0.0651 (8)
C7	0.29450 (15)	0.3406 (4)	0.8308 (2)	0.0476 (6)
C8	0.35197 (15)	0.6669 (4)	1.0533 (2)	0.0445 (6)
H1	0.2367 (14)	0.350 (4)	0.978 (2)	0.045 (6)*
H2	0.2666 (16)	0.757 (4)	0.878 (3)	0.061 (7)*
H31	0.2022 (14)	0.694 (4)	1.105 (3)	0.053 (7)*
H32	0.2191 (18)	0.919 (5)	1.043 (3)	0.072 (9)*
H41	0.063 (3)	0.830 (6)	0.980 (4)	0.110 (12)*
H42	0.100 (2)	0.862 (5)	0.855 (3)	0.083 (10)*
H51	0.077 (2)	0.455 (5)	0.970 (3)	0.082 (9)*
H52	0.017 (3)	0.546 (5)	0.833 (3)	0.095 (10)*
H61	0.1205 (19)	0.294 (5)	0.794 (3)	0.075 (9)*
H62	0.1334 (19)	0.514 (5)	0.733 (3)	0.079 (9)*
H2O	0.306 (2)	0.108 (5)	0.725 (3)	0.096 (11)*
H51N	0.471 (2)	0.822 (4)	0.785 (3)	0.069 (9)*
H52N	0.550 (2)	0.690 (6)	0.862 (3)	0.093 (11)*
H53N	0.473 (2)	0.783 (5)	0.914 (3)	0.073 (9)*
H54N	0.539 (2)	0.913 (5)	0.883 (3)	0.072 (10)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.0594 (13)	0.0984 (16)	0.1176 (17)	−0.0311 (11)	0.0484 (11)	−0.0500 (13)
O2	0.0594 (12)	0.0698 (14)	0.0782 (12)	−0.0123 (10)	0.0247 (10)	−0.0291 (10)
O3	0.0613 (12)	0.0705 (13)	0.0734 (12)	−0.0289 (10)	0.0263 (9)	−0.0155 (9)
O4	0.0444 (10)	0.0695 (12)	0.0516 (9)	0.0018 (8)	0.0080 (7)	0.0121 (9)
N	0.0458 (14)	0.0544 (15)	0.0472 (13)	−0.0041 (13)	0.0094 (12)	−0.0001 (11)
C1	0.0430 (13)	0.0538 (15)	0.0406 (12)	−0.0078 (11)	0.0119 (10)	−0.0013 (12)
C2	0.0458 (14)	0.0457 (14)	0.0427 (12)	−0.0006 (11)	0.0101 (10)	0.0020 (11)
C3	0.0527 (16)	0.0572 (18)	0.0609 (16)	0.0093 (13)	0.0111 (12)	−0.0043 (15)
C4	0.060 (2)	0.101 (3)	0.082 (2)	0.0281 (19)	0.0125 (16)	−0.002 (2)
C5	0.0366 (16)	0.123 (3)	0.084 (2)	−0.0010 (17)	0.0118 (15)	−0.022 (2)
C6	0.0411 (15)	0.092 (3)	0.0604 (17)	−0.0104 (15)	0.0107 (12)	−0.0174 (17)
C7	0.0434 (14)	0.0558 (16)	0.0433 (12)	−0.0097 (12)	0.0105 (10)	−0.0071 (11)
C8	0.0452 (13)	0.0487 (14)	0.0434 (12)	−0.0059 (12)	0.0180 (10)	−0.0092 (11)

Geometric parameters (Å, º)

O1—C7	1.189 (3)	C2—C3	1.528 (4)
O2—C7	1.315 (3)	C2—H2	0.99 (3)
O2—H2O	0.95 (4)	C3—C4	1.512 (4)
O3—C8	1.243 (3)	C3—H31	1.01 (3)
O4—C8	1.260 (3)	C3—H32	0.97 (3)
N—H51N	0.84 (3)	C4—C5	1.496 (5)
N—H52N	0.95 (4)	C4—H41	0.97 (4)
N—H53N	0.88 (3)	C4—H42	0.96 (3)
N—H54N	0.85 (4)	C5—C6	1.521 (4)
C1—C7	1.509 (3)	C5—H51	1.02 (3)
C1—C2	1.521 (3)	C5—H52	0.93 (4)
C1—C6	1.531 (4)	C6—H61	0.96 (3)
C1—H1	0.96 (2)	C6—H62	0.96 (3)
C2—C8	1.517 (3)
C7—O2—H2O	108 (2)	C5—C4—C3	111.0 (3)
H51N—N—H52N	117 (3)	C5—C4—H41	108 (2)
H51N—N—H53N	104 (3)	C3—C4—H41	110 (2)
H52N—N—H53N	116 (3)	C5—C4—H42	108.3 (18)
H51N—N—H54N	110 (3)	C3—C4—H42	110.5 (19)
H52N—N—H54N	102 (3)	H41—C4—H42	109 (3)
H53N—N—H54N	108 (3)	C4—C5—C6	111.3 (3)
C7—C1—C2	111.45 (19)	C4—C5—H51	108.0 (17)
C7—C1—C6	112.06 (19)	C6—C5—H51	106.9 (17)
C2—C1—C6	112.2 (2)	C4—C5—H52	112 (2)
C7—C1—H1	104.1 (13)	C6—C5—H52	110 (2)
C2—C1—H1	106.1 (12)	H51—C5—H52	109 (3)
C6—C1—H1	110.4 (13)	C5—C6—C1	111.3 (2)
C8—C2—C1	113.65 (19)	C5—C6—H61	110.5 (17)
C8—C2—C3	108.03 (19)	C1—C6—H61	107.0 (17)
C1—C2—C3	111.6 (2)	C5—C6—H62	111.1 (17)
C8—C2—H2	107.8 (15)	C1—C6—H62	110.5 (18)
C1—C2—H2	107.2 (14)	H61—C6—H62	106 (3)
C3—C2—H2	108.4 (15)	O1—C7—O2	122.6 (2)
C4—C3—C2	112.7 (3)	O1—C7—C1	124.6 (2)
C4—C3—H31	113.0 (13)	O2—C7—C1	112.8 (2)
C2—C3—H31	106.0 (13)	O3—C8—O4	122.0 (2)
C4—C3—H32	112.8 (16)	O3—C8—C2	119.1 (2)
C2—C3—H32	105.5 (16)	O4—C8—C2	118.8 (2)
H31—C3—H32	106 (2)
C7—C1—C2—C8	−60.4 (3)	C2—C1—C6—C5	−52.9 (4)
C6—C1—C2—C8	173.0 (2)	C2—C1—C7—O1	13.3 (3)
C7—C1—C2—C3	177.10 (19)	C6—C1—C7—O1	140.0 (3)
C6—C1—C2—C3	50.5 (3)	C2—C1—C7—O2	−166.66 (19)
C8—C2—C3—C4	−177.5 (3)	C6—C1—C7—O2	−40.0 (3)
C1—C2—C3—C4	−51.8 (3)	C1—C2—C8—O3	137.3 (2)
C2—C3—C4—C5	55.3 (4)	C3—C2—C8—O3	−98.3 (3)
C3—C4—C5—C6	−57.3 (5)	C1—C2—C8—O4	−46.4 (3)
C4—C5—C6—C1	56.3 (4)	C3—C2—C8—O4	78.0 (3)
C7—C1—C6—C5	−179.2 (3)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O2—H2O···O4^i	0.95 (3)	1.66 (3)	2.601 (3)	169 (3)
N—H51N···O3^ii	0.84 (3)	2.58 (3)	3.321 (3)	148 (2)
N—H51N···O4^ii	0.84 (3)	2.10 (3)	2.895 (3)	158 (3)
N—H52N···O4^iii	0.95 (3)	1.87 (3)	2.824 (4)	176 (3)
N—H53N···O3	0.88 (3)	1.95 (3)	2.819 (3)	168 (3)
N—H54N···O3^iv	0.86 (3)	1.96 (4)	2.806 (3)	169 (3)
C1—H1···O4	0.96 (2)	2.57 (2)	2.919 (3)	101.3 (16)

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