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The title acid salt, Na+·C4H5O2-·2C4H6O2, contains finite anions in which two cyclo­propanoic acid mol­ecules are hydrogen bonded to a cyclo­propanoate residue. Each such anion interacts with four different Na+ cations.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270100001128/bm1395sup1.cif
Contains datablocks global, I

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270100001128/bm1395Isup2.hkl
Contains datablock I

CCDC reference: 145518

Comment top

The title acid salt, (I), was obtained during an attempt to make a conventional acid salt of cyclopropanoic acid. Most monocarboxy acids, HX, form acid salts of the general type MHX2, where M is any singly-charged cation. However, Speakman (1972) noted in his review of the structures of acid salts that more complex compositions are very occasionally found, citing the examples of KH2X3, HX = acetic acid, and RbH2X3, HX = monochloroacetic acid. Salt (I) belongs to this rare class of acid salts. It appears to be identical to the compound whose cell dimensions were reported by Hwang & Donohue (1971). \sch

The asymmetric unit of (I) consists of one Na+ cation and an XH···X···HX- anion formed by linking two cyclopropanoic acid molecules, HX, to the same cyclopropanoate anion through moderate-to-strong (Jeffrey, 1997) O—H···O hydrogen bonds (see Table 2). The geometries of the three independent cyclopropanoic acid residues are consistent with an ordered arrangement of hydrogen bonds: the deprotonated acid contains C11—O bonds of nearly equal length [1.251 (2) and 1.254 (2) Å], whereas the C21—-O and C31–O bonds show the difference in length expected if O22 and O32 are protonated [1.214 (2) and 1.305 (2) Å, and 1.189 (2) and 1.325 (2) Å, respectively]. Disorder of the C32–C34 ring obscures some of its structural details, but the other two cyclopropane units show the expected shortening of the distal C—C bonds [1.465 (3) and 1.461 (3) Å] relative to the others [1.491 (3)–1.504 (3) Å; Allen, 1980].

The Na+ ions lie almost exactly on the 21 screw axes (Fig. 1). In consequence, the operations of the screw axes generate nearly linear chains of regularly spaced Na+ cations which run parallel to the b axis. The distance of 3.402 (2) Å between adjacent Na+ ions in these chains is only 0.014 Å greater than b/2. Each Na+ ion is surrounded by a distorted octahedron of O atoms (Table 1). Adjacent octahedra are linked through the O21···O31 edge and also through the η2-bridging carboxy group containing O11 and O12. Each Na+ ion is bonded to three different XH···X···HX- anions and each XH···X···HX- anion donates six electron pairs to four different Na+ ions. This highly stable arrangement uses all lone pairs on unprotonated O atoms O11, O12, O21 and O31 and the hydrogen-bond-donor properties of the O22 and O32 OH groups for inter-residue bonding.

Since Speakman's (1972) review two MH2X3 structures have been fully described and both contain the finite XH···X···HX- anions also found in (I). The cation in KH2(CH3CO2)3 (Efremov et al., 1986) is eight-coordinate. NaH2(CH3CO2)3 more closely resembles (I), with the finite XH···X···HX- anions stabilizing a chain of octahedrally coordinated Na+ cations related by a 41 screw axis; the Na—O distances [2.316 (4)–2.580 (4) Å] are less regular than those in (I) and the O···O distances in the hydrogen bonds [2.509 (4) and 2.503 (4) Å] are somewhat shorter (Perrotti & Tazzoli, 1981). Interestingly, acetic acid also forms a regular sodium salt, Na(CH3CO2), which crystallizes as a trihydrate (Doxsee & Stevens, 1990) and in two anhydrous forms (Hsu & Nordman, 1983), and a regular acid salt NaHX2 (Barrow et al., 1975); all have been structurally characterized. Though an analysis of potassium dihydrogen tris(o-chlorobenzoate) was successful (Golic & Speakman, 1975) no structural details have been published.

Experimental top

Crystals were obtained from an aqueous solution of cyclopropanoic acid and sodium hydroxide in 2:1 mole ratio. Analysis found: C 50.8, H 6.05%; calculated for C12H17NaO6: C 51.4, H 6.07%. IR (KBr discs): 3439, 3081, 3022, 2860, 2480, 1905, 1692, 1522, 1430, 1362, 1294, 1228 cm-1.

Refinement top

The carboxy H atoms, H2 and H3, were located in a ΔF synthesis. Other H atoms were positioned using stereochemical criteria and were then constrained to ride on their parent C atoms. The C32–C34 cyclopropane ring is disordered over two sites with equal probability and the parameters of the disordered atoms are therefore subject to some systematic error.

Computing details top

Data collection: CAD-4 EXPRESS (Enraf Nonius, 1992); cell refinement: CAD-4 EXPRESS; data reduction: XCAD4 (Harms & Wocadlo , 1995); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: WinGX (Farrugia, 1999).

Figures top
[Figure 1] Fig. 1. (a) A view of the coordination of the Na+ ion showing 20% displacement ellipsoids and the atom labelling. Only one component of the disordered C32–C34 ring is displayed. (b) A view of one complete anion, formed by the O11···HO32i and O12···HO22ii hydrogen bonds, and of the four Na+ cations to which it bonds. These cations are part of a chain running parallel to the b axis. [Symmetry codes: (i) 1/2 - x, 1/2 + y, 3/2 - z; (ii) 1/2 - x, y - 1/2, 3/2 - z; (iii) x, -1 + y, z.]
(I) top
Crystal data top
NaH2(C4H5O2)3F(000) = 592
Mr = 280.25Dx = 1.337 Mg m3
Dm = 1.34 Mg m3
Dm measured by flotation in heptane/1,2-dichloroethane
Monoclinic, P21/nMo Kα radiation, λ = 0.71073 Å
a = 12.3629 (7) ÅCell parameters from 25 reflections
b = 6.7768 (4) Åθ = 18.3–23.8°
c = 16.9374 (12) ŵ = 0.13 mm1
β = 101.151 (6)°T = 294 K
V = 1392.24 (15) Å3Needle, colourless
Z = 40.49 × 0.21 × 0.11 mm
Data collection top
Enraf Nonius CAD4
diffractometer
θmax = 27°, θmin = 2.3°
ω/2θ scansh = 152
4477 measured reflectionsk = 81
3357 independent reflectionsl = 2321
2175 reflections with I > 2σ(I)3 standard reflections every 184 reflections
Rint = 0.018 intensity decay: none
Refinement top
Refinement on F20 restraints
Least-squares matrix: fullH atoms treated by a mixture of independent and constrained refinement
R[F2 > 2σ(F2)] = 0.042Calculated w = 1/[σ2(Fo2) + (0.0556P)2 + 0.352P]
where P = (Fo2 + 2Fc2)/3
wR(F2) = 0.125(Δ/σ)max = 0.001
S = 1.02Δρmax = 0.26 e Å3
3357 reflectionsΔρmin = 0.24 e Å3
207 parameters
Crystal data top
NaH2(C4H5O2)3V = 1392.24 (15) Å3
Mr = 280.25Z = 4
Monoclinic, P21/nMo Kα radiation
a = 12.3629 (7) ŵ = 0.13 mm1
b = 6.7768 (4) ÅT = 294 K
c = 16.9374 (12) Å0.49 × 0.21 × 0.11 mm
β = 101.151 (6)°
Data collection top
Enraf Nonius CAD4
diffractometer
Rint = 0.018
4477 measured reflections3 standard reflections every 184 reflections
3357 independent reflections intensity decay: none
2175 reflections with I > 2σ(I)
Refinement top
R[F2 > 2σ(F2)] = 0.0420 restraints
wR(F2) = 0.125H atoms treated by a mixture of independent and constrained refinement
S = 1.02Δρmax = 0.26 e Å3
3357 reflectionsΔρmin = 0.24 e Å3
207 parameters
Special details top

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/UeqOcc. (<1)
Na10.25832 (6)0.26125 (9)0.75806 (4)0.0424 (2)
O110.43738 (10)0.16489 (18)0.74499 (8)0.0480 (3)
O120.38710 (11)0.11652 (19)0.68568 (8)0.0549 (4)
C110.45721 (14)0.0169 (2)0.70601 (10)0.0370 (4)
C120.56531 (15)0.0031 (3)0.68133 (12)0.0482 (5)
H120.57510.12260.65090.058*
C130.66778 (16)0.0764 (4)0.73416 (15)0.0661 (6)
H13A0.66010.13960.78420.079*
H13B0.73570.00290.73660.079*
C140.62219 (17)0.1788 (4)0.65887 (13)0.0614 (6)
H14A0.6620.16820.6150.074*
H14B0.58640.30490.66260.074*
O210.23813 (10)0.00417 (17)0.84734 (7)0.0432 (3)
O220.11666 (13)0.1073 (2)0.91684 (9)0.0671 (5)
H20.107 (2)0.207 (5)0.8780 (17)0.107 (10)*
C210.18570 (14)0.0252 (2)0.90041 (10)0.0388 (4)
C220.19714 (15)0.2029 (3)0.95117 (10)0.0452 (4)
H220.24240.30790.93450.054*
C230.20379 (19)0.1860 (3)1.04051 (11)0.0584 (5)
H23A0.25380.27391.07510.07*
H23B0.19690.05561.06260.07*
C240.10587 (18)0.2725 (4)0.99023 (11)0.0595 (6)
H24A0.03840.19560.98150.071*
H24B0.09540.41380.9940.071*
O310.12784 (16)0.0376 (2)0.66665 (9)0.0677 (4)
O320.04255 (14)0.0599 (3)0.66820 (13)0.0839 (6)
H30.011 (3)0.145 (5)0.7033 (18)0.121 (12)*
C310.0311 (3)0.0585 (3)0.64551 (13)0.0683 (7)
C320.0045 (4)0.2197 (7)0.5908 (3)0.0438 (10)0.5
H32A0.06450.29410.57440.053*0.5
C330.1061 (4)0.1989 (8)0.5310 (3)0.0599 (12)0.5
H33A0.11220.25990.47860.072*0.5
H33B0.1460.07570.53110.072*0.5
C340.1004 (4)0.3288 (7)0.6005 (3)0.0556 (11)0.5
H34A0.1370.28570.64320.067*0.5
H34B0.10330.46990.59070.067*0.5
C32B0.0573 (6)0.2146 (10)0.5948 (4)0.0827 (19)0.5
H32B0.13490.20390.59920.099*0.5
C33B0.0323 (8)0.2610 (9)0.5186 (3)0.100 (2)0.5
H33C0.09340.28340.47410.119*0.5
H33D0.03170.19870.5040.119*0.5
C34B0.0133 (5)0.4075 (7)0.5843 (3)0.0745 (13)0.5
H34C0.06220.43460.61040.089*0.5
H34D0.0630.51940.58050.089*0.5
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Na10.0504 (4)0.0291 (3)0.0528 (4)0.0021 (3)0.0224 (3)0.0055 (3)
O110.0455 (7)0.0366 (7)0.0650 (8)0.0007 (6)0.0180 (6)0.0174 (6)
O120.0624 (8)0.0398 (7)0.0701 (9)0.0213 (7)0.0317 (7)0.0164 (7)
C110.0435 (9)0.0302 (8)0.0394 (8)0.0012 (7)0.0136 (7)0.0009 (7)
C120.0481 (10)0.0413 (10)0.0595 (11)0.0009 (9)0.0209 (9)0.0129 (9)
C130.0411 (10)0.0747 (15)0.0795 (15)0.0116 (11)0.0043 (10)0.0067 (12)
C140.0485 (11)0.0706 (14)0.0689 (13)0.0173 (11)0.0209 (10)0.0040 (12)
O210.0553 (7)0.0325 (6)0.0473 (7)0.0061 (6)0.0238 (6)0.0052 (5)
O220.0866 (11)0.0563 (9)0.0722 (10)0.0322 (8)0.0497 (9)0.0226 (8)
C210.0464 (9)0.0331 (9)0.0383 (8)0.0031 (8)0.0117 (7)0.0014 (7)
C220.0544 (11)0.0392 (10)0.0448 (9)0.0046 (8)0.0164 (8)0.0088 (8)
C230.0751 (14)0.0576 (12)0.0399 (10)0.0075 (11)0.0043 (9)0.0075 (9)
C240.0636 (13)0.0662 (14)0.0492 (11)0.0134 (11)0.0121 (10)0.0140 (10)
O310.0902 (12)0.0523 (9)0.0622 (9)0.0228 (9)0.0192 (9)0.0042 (7)
O320.0630 (10)0.0610 (11)0.1165 (15)0.0008 (9)0.0106 (10)0.0366 (11)
C310.115 (2)0.0337 (10)0.0494 (12)0.0105 (13)0.0027 (13)0.0081 (9)
C320.031 (2)0.040 (2)0.059 (2)0.004 (2)0.0061 (19)0.0160 (17)
C330.058 (3)0.058 (3)0.056 (3)0.003 (2)0.009 (2)0.018 (2)
C340.049 (2)0.040 (2)0.075 (3)0.014 (2)0.005 (2)0.009 (2)
C32B0.063 (4)0.058 (4)0.117 (5)0.005 (4)0.006 (4)0.036 (3)
C33B0.163 (7)0.066 (4)0.055 (3)0.033 (4)0.015 (4)0.001 (3)
C34B0.092 (4)0.056 (3)0.073 (3)0.011 (3)0.010 (3)0.007 (2)
Geometric parameters (Å, º) top
Na1—O12i2.3429 (14)O22—C211.305 (2)
Na1—O112.3590 (14)C21—C221.471 (2)
Na1—O212.3939 (13)C22—C241.491 (3)
Na1—O21i2.3972 (13)C22—C231.504 (2)
Na1—O312.5162 (18)C23—C241.461 (3)
Na1—O31i2.534 (2)O31—C311.189 (3)
Na1—Na1ii3.4024 (2)O31—Na1ii2.534 (2)
Na1—Na1i3.4024 (2)O32—C311.325 (3)
O11—C111.251 (2)C31—C321.429 (5)
O12—C111.254 (2)C31—C32B1.639 (7)
O12—Na1ii2.3429 (14)C32—C341.529 (6)
C11—C121.482 (2)C32—C331.542 (6)
C12—C131.502 (3)C33—C341.459 (7)
C12—C141.504 (3)C32B—C33B1.419 (10)
C13—C141.465 (3)C32B—C34B1.440 (8)
O21—C211.214 (2)C33B—C34B1.477 (8)
O21—Na1ii2.3972 (13)
O12i—Na1—O11160.70 (6)C11—C12—C14119.22 (17)
O12i—Na1—O2180.02 (5)C13—C12—C1458.35 (14)
O11—Na1—O2193.77 (5)C14—C13—C1260.87 (14)
O12i—Na1—O21i101.21 (5)C13—C14—C1260.78 (15)
O11—Na1—O21i87.77 (5)C21—O21—Na1133.77 (11)
O21—Na1—O21i171.08 (5)C21—O21—Na1ii124.26 (11)
O12i—Na1—O3190.70 (6)Na1—O21—Na1ii90.50 (4)
O11—Na1—O31106.08 (6)O21—C21—O22122.81 (16)
O21—Na1—O3178.66 (5)O21—C21—C22121.62 (16)
O21i—Na1—O3192.47 (5)O22—C21—C22115.57 (15)
O12i—Na1—O31i85.94 (6)C21—C22—C24121.55 (17)
O11—Na1—O31i79.16 (5)C21—C22—C23120.41 (17)
O21—Na1—O31i110.67 (5)C24—C22—C2358.42 (13)
O21i—Na1—O31i78.25 (5)C24—C23—C2260.34 (13)
O31—Na1—O31i169.29 (6)C23—C24—C2261.24 (13)
O12i—Na1—Na1ii110.21 (5)C31—O31—Na1126.97 (16)
O11—Na1—Na1ii76.12 (4)C31—O31—Na1ii131.93 (14)
O21—Na1—Na1ii44.79 (3)Na1—O31—Na1ii84.72 (6)
O21i—Na1—Na1ii127.60 (5)O31—C31—O32123.2 (2)
O31—Na1—Na1ii47.86 (5)O31—C31—C32112.2 (3)
O31i—Na1—Na1ii142.70 (5)O32—C31—C32124.5 (3)
O12i—Na1—Na1i68.98 (4)O31—C31—C32B139.8 (3)
O11—Na1—Na1i108.15 (4)O32—C31—C32B96.8 (3)
O21—Na1—Na1i141.90 (4)C32—C31—C32B28.4 (2)
O21i—Na1—Na1i44.71 (3)C31—C32—C34113.2 (4)
O31—Na1—Na1i121.94 (5)C31—C32—C33114.8 (4)
O31i—Na1—Na1i47.42 (4)C34—C32—C3356.7 (3)
Na1ii—Na1—Na1i169.60 (5)C34—C33—C3261.2 (3)
C11—O11—Na1123.69 (11)C33—C34—C3262.1 (3)
C11—O12—Na1ii133.42 (11)C33B—C32B—C34B62.2 (4)
O11—C11—O12121.84 (15)C33B—C32B—C31112.3 (7)
O11—C11—C12120.10 (15)C34B—C32B—C31114.9 (5)
O12—C11—C12118.05 (15)C32B—C33B—C34B59.6 (4)
C11—C12—C13120.14 (17)C32B—C34B—C33B58.2 (5)
O12i—Na1—O11—C11142.71 (16)C21—C22—C23—C24110.6 (2)
O21—Na1—O11—C1172.43 (14)C21—C22—C24—C23108.6 (2)
O21i—Na1—O11—C1198.77 (14)O12i—Na1—O31—C3123.32 (19)
O31—Na1—O11—C116.84 (15)O11—Na1—O31—C31166.32 (18)
O31i—Na1—O11—C11177.23 (14)O21—Na1—O31—C31103.00 (18)
Na1ii—Na1—O11—C1130.92 (13)O21i—Na1—O31—C3177.93 (18)
Na1i—Na1—O11—C11139.20 (13)O31i—Na1—O31—C3148.2 (2)
Na1—O11—C11—O1216.2 (2)Na1ii—Na1—O31—C31140.4 (2)
Na1—O11—C11—C12162.76 (13)Na1i—Na1—O31—C3142.2 (2)
Na1ii—O12—C11—O1129.3 (3)O12i—Na1—O31—Na1ii117.06 (5)
Na1ii—O12—C11—C12151.69 (14)O11—Na1—O31—Na1ii53.30 (5)
O11—C11—C12—C1333.4 (3)O21—Na1—O31—Na1ii37.38 (4)
O12—C11—C12—C13147.62 (19)O21i—Na1—O31—Na1ii141.69 (5)
O11—C11—C12—C1434.9 (3)O31i—Na1—O31—Na1ii171.39 (17)
O12—C11—C12—C14144.12 (18)Na1i—Na1—O31—Na1ii177.47 (5)
C11—C12—C13—C14107.8 (2)Na1—O31—C31—O32112.1 (2)
C11—C12—C14—C13109.3 (2)Na1ii—O31—C31—O329.3 (4)
O12i—Na1—O21—C219.52 (16)Na1—O31—C31—C3270.3 (3)
O11—Na1—O21—C21152.07 (16)Na1ii—O31—C31—C32168.3 (2)
O21i—Na1—O21—C21108.3 (3)Na1—O31—C31—C32B61.9 (6)
O31—Na1—O21—C21102.27 (17)Na1ii—O31—C31—C32B176.7 (5)
O31i—Na1—O21—C2172.24 (17)O31—C31—C32—C34145.5 (3)
Na1ii—Na1—O21—C21141.99 (18)O32—C31—C32—C3437.0 (5)
Na1i—Na1—O21—C2125.9 (2)C32B—C31—C32—C3423.0 (6)
O12i—Na1—O21—Na1ii132.46 (6)O31—C31—C32—C33151.9 (3)
O11—Na1—O21—Na1ii65.95 (5)O32—C31—C32—C3325.7 (5)
O21i—Na1—O21—Na1ii33.7 (2)C32B—C31—C32—C3339.6 (7)
O31—Na1—O21—Na1ii39.71 (5)C31—C32—C33—C34102.4 (4)
O31i—Na1—O21—Na1ii145.77 (6)C31—C32—C34—C33105.3 (5)
Na1i—Na1—O21—Na1ii167.92 (8)O31—C31—C32B—C33B51.3 (8)
Na1—O21—C21—O225.0 (3)O32—C31—C32B—C33B133.8 (5)
Na1ii—O21—C21—O22126.86 (17)C32—C31—C32B—C33B34.6 (7)
Na1—O21—C21—C22174.44 (12)O31—C31—C32B—C34B17.3 (9)
Na1ii—O21—C21—C2253.7 (2)O32—C31—C32B—C34B157.6 (6)
O21—C21—C22—C24153.56 (18)C32—C31—C32B—C34B33.9 (5)
O22—C21—C22—C2427.0 (3)C31—C32B—C33B—C34B107.4 (5)
O21—C21—C22—C23137.05 (19)C31—C32B—C34B—C33B103.2 (7)
O22—C21—C22—C2342.4 (3)
Symmetry codes: (i) x+1/2, y+1/2, z+3/2; (ii) x+1/2, y1/2, z+3/2.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O22—H2···O12i0.93 (3)1.62 (3)2.5475 (18)171 (3)
O32—H3···O11ii0.86 (3)1.72 (3)2.567 (2)167 (3)
Symmetry codes: (i) x+1/2, y+1/2, z+3/2; (ii) x+1/2, y1/2, z+3/2.

Experimental details

Crystal data
Chemical formulaNaH2(C4H5O2)3
Mr280.25
Crystal system, space groupMonoclinic, P21/n
Temperature (K)294
a, b, c (Å)12.3629 (7), 6.7768 (4), 16.9374 (12)
β (°) 101.151 (6)
V3)1392.24 (15)
Z4
Radiation typeMo Kα
µ (mm1)0.13
Crystal size (mm)0.49 × 0.21 × 0.11
Data collection
DiffractometerEnraf Nonius CAD4
diffractometer
Absorption correction
No. of measured, independent and
observed [I > 2σ(I)] reflections
4477, 3357, 2175
Rint0.018
(sin θ/λ)max1)0.639
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.042, 0.125, 1.02
No. of reflections3357
No. of parameters207
H-atom treatmentH atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å3)0.26, 0.24

Computer programs: CAD-4 EXPRESS (Enraf Nonius, 1992), CAD-4 EXPRESS, XCAD4 (Harms & Wocadlo , 1995), SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), ORTEP-3 (Farrugia, 1997), WinGX (Farrugia, 1999).

Selected geometric parameters (Å, º) top
Na1—O12i2.3429 (14)Na1—O21i2.3972 (13)
Na1—O112.3590 (14)Na1—O312.5162 (18)
Na1—O212.3939 (13)Na1—O31i2.534 (2)
O12i—Na1—O11160.70 (6)O31—Na1—O31i169.29 (6)
O21—Na1—O21i171.08 (5)
Symmetry code: (i) x+1/2, y+1/2, z+3/2.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O22—H2···O12i0.93 (3)1.62 (3)2.5475 (18)171 (3)
O32—H3···O11ii0.86 (3)1.72 (3)2.567 (2)167 (3)
Symmetry codes: (i) x+1/2, y+1/2, z+3/2; (ii) x+1/2, y1/2, z+3/2.
 

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