Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S010827010901957X/fn3017sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S010827010901957X/fn3017Isup2.hkl |
K2[Mn3(HPO3)4] was prepared in a 23 ml Teflon-lined steel autoclave from a reaction mixture containing (C2H3O2)3Mn.2H2O (Acros Organics, 98%), H3PO3 (Aldrich, 99%), K2CO3 (Merck, 99%) and deionized water in the molar ratio 0.2:1.5:0.8:28. After 72 h at 443 K, the vessel was slowly cooled to room temperature. Large light-pink crystals were recovered by vacuum filtration, washed with deionized water and dried in a desiccator.
Both H atoms were located in a difference Fourier map and their Uiso values were constrained to be 1.2Ueq of the corresponding P atom.
Data collection: COLLECT (Nonius, 1998); cell refinement: DIRAX/LSQ (Duisenberg, 1992); data reduction: EVALCCD (Duisenberg, 1998); program(s) used to solve structure: SIR97 (Altomare et al., 1999); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg, 2005); software used to prepare material for publication: WinGX (Farrugia, 1999).
K2[Mn3(HPO3)4] | Dx = 3.078 Mg m−3 |
Mr = 562.93 | Mo Kα radiation, λ = 0.71073 Å |
Trigonal, R3m | Cell parameters from 7370 reflections |
Hall symbol: -R 3 2" | θ = 2.9–42.1° |
a = 5.4489 (1) Å | µ = 4.34 mm−1 |
c = 35.4321 (9) Å | T = 293 K |
V = 911.05 (3) Å3 | Prism, light pink |
Z = 3 | 0.14 × 0.11 × 0.10 mm |
F(000) = 819 |
Nonius KappaCCD diffractometer | 761 reflections with I > 2σ(I) |
CCD rotation images, thick slices scans | Rint = 0.024 |
Absorption correction: multi-scan (SADABS; Sheldrick, 2002) | θmax = 42.0°, θmin = 4.4° |
Tmin = 0.544, Tmax = 0.647 | h = −5→10 |
5846 measured reflections | k = −10→8 |
864 independent reflections | l = −66→63 |
Refinement on F2 | Only H-atom coordinates refined |
Least-squares matrix: full | w = 1/[σ2(Fo2) + (0.0304P)2 + 1.4276P] where P = (Fo2 + 2Fc2)/3 |
R[F2 > 2σ(F2)] = 0.023 | (Δ/σ)max < 0.001 |
wR(F2) = 0.063 | Δρmax = 1.76 e Å−3 |
S = 1.17 | Δρmin = −1.06 e Å−3 |
864 reflections | Extinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
30 parameters | Extinction coefficient: 0.0016 (4) |
0 restraints |
K2[Mn3(HPO3)4] | Z = 3 |
Mr = 562.93 | Mo Kα radiation |
Trigonal, R3m | µ = 4.34 mm−1 |
a = 5.4489 (1) Å | T = 293 K |
c = 35.4321 (9) Å | 0.14 × 0.11 × 0.10 mm |
V = 911.05 (3) Å3 |
Nonius KappaCCD diffractometer | 864 independent reflections |
Absorption correction: multi-scan (SADABS; Sheldrick, 2002) | 761 reflections with I > 2σ(I) |
Tmin = 0.544, Tmax = 0.647 | Rint = 0.024 |
5846 measured reflections |
R[F2 > 2σ(F2)] = 0.023 | 0 restraints |
wR(F2) = 0.063 | Only H-atom coordinates refined |
S = 1.17 | Δρmax = 1.76 e Å−3 |
864 reflections | Δρmin = −1.06 e Å−3 |
30 parameters |
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. |
x | y | z | Uiso*/Ueq | ||
Mn1 | 0 | 0 | 0 | 0.01057 (9) | |
Mn2 | 0 | 0 | 0.084653 (10) | 0.01053 (8) | |
P1 | 0.3333 | 0.6667 | 0.107906 (17) | 0.00954 (10) | |
P2 | 0.6667 | 0.3333 | 0.029499 (16) | 0.00867 (10) | |
O1 | 0.3539 (2) | 0.17694 (10) | 0.04098 (3) | 0.01311 (16) | |
O2 | 0.17917 (11) | 0.3583 (2) | 0.12068 (3) | 0.01484 (17) | |
K1 | 0.6667 | 0.3333 | 0.147069 (17) | 0.01778 (11) | |
H1 | 0.3333 | 0.6667 | 0.0679 (15) | 0.021* | |
H2 | 0.6667 | 0.3333 | −0.0077 (13) | 0.021* |
U11 | U22 | U33 | U12 | U13 | U23 | |
Mn1 | 0.01039 (12) | 0.01039 (12) | 0.01092 (18) | 0.00520 (6) | 0 | 0 |
Mn2 | 0.01011 (10) | 0.01011 (10) | 0.01137 (14) | 0.00506 (5) | 0 | 0 |
P1 | 0.00850 (13) | 0.00850 (13) | 0.0116 (2) | 0.00425 (7) | 0 | 0 |
P2 | 0.00742 (13) | 0.00742 (13) | 0.0112 (2) | 0.00371 (7) | 0 | 0 |
O1 | 0.0072 (3) | 0.0132 (3) | 0.0169 (4) | 0.00362 (17) | 0.0008 (3) | 0.00039 (14) |
O2 | 0.0163 (3) | 0.0082 (3) | 0.0173 (4) | 0.00411 (17) | −0.00008 (15) | −0.0002 (3) |
K1 | 0.01614 (14) | 0.01614 (14) | 0.0211 (2) | 0.00807 (7) | 0 | 0 |
Mn1—O1 | 2.2129 (10) | P1—K1xi | 3.4384 (4) |
Mn1—O1i | 2.2129 (10) | P1—K1vii | 3.4384 (4) |
Mn1—O1ii | 2.2129 (10) | P1—K1 | 3.4384 (4) |
Mn1—O1iii | 2.2129 (10) | P1—H1 | 1.42 (5) |
Mn1—O1iv | 2.2129 (10) | P2—O1xii | 1.5311 (10) |
Mn1—O1v | 2.2129 (10) | P2—O1xiii | 1.5311 (10) |
Mn1—Mn2iii | 2.9994 (4) | P2—O1 | 1.5311 (10) |
Mn1—Mn2 | 2.9994 (4) | P2—H2 | 1.32 (5) |
Mn2—O2 | 2.1186 (11) | O2—K1vi | 2.8740 (12) |
Mn2—O2i | 2.1186 (11) | O2—K1vii | 2.8829 (9) |
Mn2—O2ii | 2.1186 (11) | O2—K1 | 2.8829 (9) |
Mn2—O1ii | 2.2766 (10) | K1—O2xiv | 2.8740 (12) |
Mn2—O1 | 2.2766 (10) | K1—O2vi | 2.8740 (12) |
Mn2—O1i | 2.2766 (10) | K1—O2xv | 2.8741 (12) |
Mn2—K1vi | 3.6004 (7) | K1—O2xii | 2.8829 (11) |
Mn2—K1vii | 3.8455 (4) | K1—O2ii | 2.8829 (9) |
Mn2—K1 | 3.8455 (4) | K1—O2xvi | 2.8829 (9) |
Mn2—K1viii | 3.8455 (4) | K1—O2xiii | 2.8829 (9) |
P1—O2ix | 1.5237 (10) | K1—O2x | 2.8829 (11) |
P1—O2x | 1.5237 (11) | K1—P1xvii | 3.4384 (4) |
P1—O2 | 1.5237 (10) | K1—P1xvi | 3.4384 (4) |
O1—Mn1—O1i | 81.62 (4) | O2—P1—K1 | 56.17 (3) |
O1—Mn1—O1ii | 81.62 (4) | K1xi—P1—K1 | 104.814 (15) |
O1i—Mn1—O1ii | 81.62 (4) | K1vii—P1—K1 | 104.814 (15) |
O1—Mn1—O1iii | 180.00 (5) | O2ix—P1—H1 | 107.28 (5) |
O1i—Mn1—O1iii | 98.38 (4) | O2x—P1—H1 | 107.28 (5) |
O1ii—Mn1—O1iii | 98.38 (4) | O2—P1—H1 | 107.28 (5) |
O1—Mn1—O1iv | 98.38 (4) | K1xi—P1—H1 | 113.802 (13) |
O1i—Mn1—O1iv | 180.00 (4) | K1vii—P1—H1 | 113.802 (13) |
O1ii—Mn1—O1iv | 98.38 (4) | K1—P1—H1 | 113.802 (13) |
O1iii—Mn1—O1iv | 81.62 (4) | O1xii—P2—O1xiii | 113.21 (4) |
O1—Mn1—O1v | 98.38 (4) | O1xii—P2—O1 | 113.21 (4) |
O1i—Mn1—O1v | 98.38 (4) | O1xiii—P2—O1 | 113.21 (4) |
O1ii—Mn1—O1v | 180.00 (4) | O1xii—P2—H2 | 105.41 (4) |
O1iii—Mn1—O1v | 81.62 (4) | O1xiii—P2—H2 | 105.41 (4) |
O1iv—Mn1—O1v | 81.62 (4) | O1—P2—H2 | 105.41 (4) |
O1—Mn1—Mn2iii | 131.01 (3) | P2—O1—Mn1 | 123.59 (6) |
O1i—Mn1—Mn2iii | 131.01 (3) | P2—O1—Mn2 | 152.59 (7) |
O1ii—Mn1—Mn2iii | 131.01 (3) | Mn1—O1—Mn2 | 83.83 (3) |
O1iii—Mn1—Mn2iii | 48.99 (3) | P1—O2—Mn2 | 125.68 (7) |
O1iv—Mn1—Mn2iii | 48.99 (3) | P1—O2—K1vi | 143.31 (6) |
O1v—Mn1—Mn2iii | 48.99 (3) | Mn2—O2—K1vi | 91.01 (4) |
O1—Mn1—Mn2 | 48.99 (3) | P1—O2—K1vii | 97.78 (2) |
O1i—Mn1—Mn2 | 48.99 (3) | Mn2—O2—K1vii | 99.37 (2) |
O1ii—Mn1—Mn2 | 48.99 (3) | K1vi—O2—K1vii | 73.36 (2) |
O1iii—Mn1—Mn2 | 131.01 (3) | P1—O2—K1 | 97.78 (2) |
O1iv—Mn1—Mn2 | 131.01 (3) | Mn2—O2—K1 | 99.37 (2) |
O1v—Mn1—Mn2 | 131.01 (3) | K1vi—O2—K1 | 73.36 (2) |
Mn2iii—Mn1—Mn2 | 180 | K1vii—O2—K1 | 141.83 (5) |
O2—Mn2—O2i | 87.45 (4) | O2xiv—K1—O2vi | 61.26 (4) |
O2—Mn2—O2ii | 87.45 (4) | O2xiv—K1—O2xv | 61.26 (4) |
O2i—Mn2—O2ii | 87.45 (4) | O2vi—K1—O2xv | 61.26 (4) |
O2—Mn2—O1ii | 174.23 (4) | O2xiv—K1—O2xii | 106.64 (2) |
O2i—Mn2—O1ii | 96.71 (3) | O2vi—K1—O2xii | 76.63 (4) |
O2ii—Mn2—O1ii | 96.71 (3) | O2xv—K1—O2xii | 137.036 (17) |
O2—Mn2—O1 | 96.71 (3) | O2xiv—K1—O2ii | 137.036 (17) |
O2i—Mn2—O1 | 174.23 (4) | O2vi—K1—O2ii | 76.63 (4) |
O2ii—Mn2—O1 | 96.71 (3) | O2xv—K1—O2ii | 106.64 (2) |
O1ii—Mn2—O1 | 78.87 (4) | O2xii—K1—O2ii | 51.84 (4) |
O2—Mn2—O1i | 96.71 (3) | O2xiv—K1—O2xvi | 76.63 (4) |
O2i—Mn2—O1i | 96.71 (3) | O2vi—K1—O2xvi | 106.64 (2) |
O2ii—Mn2—O1i | 174.23 (4) | O2xv—K1—O2xvi | 137.036 (17) |
O1ii—Mn2—O1i | 78.87 (4) | O2xii—K1—O2xvi | 61.06 (4) |
O1—Mn2—O1i | 78.87 (4) | O2ii—K1—O2xvi | 110.01 (2) |
O2—Mn2—Mn1 | 127.05 (3) | O2xiv—K1—O2xiii | 76.63 (4) |
O2i—Mn2—Mn1 | 127.05 (3) | O2vi—K1—O2xiii | 137.036 (17) |
O2ii—Mn2—Mn1 | 127.05 (3) | O2xv—K1—O2xiii | 106.64 (2) |
O1ii—Mn2—Mn1 | 47.18 (3) | O2xii—K1—O2xiii | 110.01 (2) |
O1—Mn2—Mn1 | 47.18 (3) | O2ii—K1—O2xiii | 141.83 (5) |
O1i—Mn2—Mn1 | 47.18 (3) | O2xvi—K1—O2xiii | 51.84 (4) |
O2—Mn2—K1vi | 52.95 (3) | O2xiv—K1—O2 | 137.035 (17) |
O2i—Mn2—K1vi | 52.95 (3) | O2vi—K1—O2 | 106.64 (2) |
O2ii—Mn2—K1vi | 52.95 (3) | O2xv—K1—O2 | 76.63 (4) |
O1ii—Mn2—K1vi | 132.82 (3) | O2xii—K1—O2 | 110.01 (2) |
O1—Mn2—K1vi | 132.82 (3) | O2ii—K1—O2 | 61.06 (4) |
O1i—Mn2—K1vi | 132.82 (3) | O2xvi—K1—O2 | 141.83 (5) |
Mn1—Mn2—K1vi | 180 | O2xiii—K1—O2 | 110.01 (2) |
O2—Mn2—K1vii | 47.704 (10) | O2xiv—K1—O2x | 106.64 (2) |
O2i—Mn2—K1vii | 47.704 (10) | O2vi—K1—O2x | 137.035 (17) |
O2ii—Mn2—K1vii | 107.85 (3) | O2xv—K1—O2x | 76.63 (4) |
O1ii—Mn2—K1vii | 133.703 (6) | O2xii—K1—O2x | 141.83 (5) |
O1—Mn2—K1vii | 133.703 (6) | O2ii—K1—O2x | 110.01 (2) |
O1i—Mn2—K1vii | 77.93 (3) | O2xvi—K1—O2x | 110.01 (2) |
Mn1—Mn2—K1vii | 125.107 (8) | O2xiii—K1—O2x | 61.06 (4) |
K1vi—Mn2—K1vii | 54.893 (8) | O2—K1—O2x | 51.84 (4) |
O2—Mn2—K1 | 47.704 (10) | O2xiv—K1—P1xvii | 126.548 (12) |
O2i—Mn2—K1 | 107.85 (3) | O2vi—K1—P1xvii | 77.76 (2) |
O2ii—Mn2—K1 | 47.705 (10) | O2xv—K1—P1xvii | 126.548 (12) |
O1ii—Mn2—K1 | 133.703 (6) | O2xii—K1—P1xvii | 26.05 (2) |
O1—Mn2—K1 | 77.93 (3) | O2ii—K1—P1xvii | 26.05 (2) |
O1i—Mn2—K1 | 133.703 (6) | O2xvi—K1—P1xvii | 84.64 (2) |
Mn1—Mn2—K1 | 125.107 (8) | O2xiii—K1—P1xvii | 126.81 (3) |
K1vi—Mn2—K1 | 54.894 (8) | O2—K1—P1xvii | 84.64 (2) |
K1vii—Mn2—K1 | 90.223 (12) | O2x—K1—P1xvii | 126.81 (3) |
O2—Mn2—K1viii | 107.85 (3) | O2xiv—K1—P1xvi | 77.76 (2) |
O2i—Mn2—K1viii | 47.705 (10) | O2vi—K1—P1xvi | 126.548 (12) |
O2ii—Mn2—K1viii | 47.705 (10) | O2xv—K1—P1xvi | 126.548 (12) |
O1ii—Mn2—K1viii | 77.93 (3) | O2xii—K1—P1xvi | 84.64 (2) |
O1—Mn2—K1viii | 133.703 (6) | O2ii—K1—P1xvi | 126.81 (3) |
O1i—Mn2—K1viii | 133.703 (6) | O2xvi—K1—P1xvi | 26.05 (2) |
Mn1—Mn2—K1viii | 125.107 (8) | O2xiii—K1—P1xvi | 26.05 (2) |
K1vi—Mn2—K1viii | 54.894 (8) | O2—K1—P1xvi | 126.81 (3) |
K1vii—Mn2—K1viii | 90.223 (12) | O2x—K1—P1xvi | 84.64 (2) |
K1—Mn2—K1viii | 90.223 (12) | P1xvii—K1—P1xvi | 104.814 (15) |
O2ix—P1—O2x | 111.57 (4) | O2xiv—K1—P1 | 126.547 (12) |
O2ix—P1—O2 | 111.57 (4) | O2vi—K1—P1 | 126.547 (12) |
O2x—P1—O2 | 111.57 (4) | O2xv—K1—P1 | 77.76 (2) |
O2ix—P1—K1xi | 56.173 (14) | O2xii—K1—P1 | 126.81 (3) |
O2x—P1—K1xi | 56.173 (14) | O2ii—K1—P1 | 84.64 (2) |
O2—P1—K1xi | 138.92 (5) | O2xvi—K1—P1 | 126.81 (3) |
O2ix—P1—K1vii | 56.173 (15) | O2xiii—K1—P1 | 84.64 (2) |
O2x—P1—K1vii | 138.92 (5) | O2—K1—P1 | 26.05 (2) |
O2—P1—K1vii | 56.173 (15) | O2x—K1—P1 | 26.05 (2) |
K1xi—P1—K1vii | 104.814 (15) | P1xvii—K1—P1 | 104.814 (15) |
O2ix—P1—K1 | 138.92 (5) | P1xvi—K1—P1 | 104.814 (15) |
O2x—P1—K1 | 56.173 (14) |
Symmetry codes: (i) −y, x−y, z; (ii) −x+y, −x, z; (iii) −x, −y, −z; (iv) y, −x+y, −z; (v) x−y, x, −z; (vi) −x+2/3, −y+1/3, −z+1/3; (vii) x−1, y, z; (viii) x−1, y−1, z; (ix) −x+y, −x+1, z; (x) −y+1, x−y+1, z; (xi) x, y+1, z; (xii) −y+1, x−y, z; (xiii) −x+y+1, −x+1, z; (xiv) y+2/3, −x+y+1/3, −z+1/3; (xv) x−y+2/3, x+1/3, −z+1/3; (xvi) x+1, y, z; (xvii) x, y−1, z. |
Experimental details
Crystal data | |
Chemical formula | K2[Mn3(HPO3)4] |
Mr | 562.93 |
Crystal system, space group | Trigonal, R3m |
Temperature (K) | 293 |
a, c (Å) | 5.4489 (1), 35.4321 (9) |
V (Å3) | 911.05 (3) |
Z | 3 |
Radiation type | Mo Kα |
µ (mm−1) | 4.34 |
Crystal size (mm) | 0.14 × 0.11 × 0.10 |
Data collection | |
Diffractometer | Nonius KappaCCD diffractometer |
Absorption correction | Multi-scan (SADABS; Sheldrick, 2002) |
Tmin, Tmax | 0.544, 0.647 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 5846, 864, 761 |
Rint | 0.024 |
(sin θ/λ)max (Å−1) | 0.941 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.023, 0.063, 1.17 |
No. of reflections | 864 |
No. of parameters | 30 |
H-atom treatment | Only H-atom coordinates refined |
Δρmax, Δρmin (e Å−3) | 1.76, −1.06 |
Computer programs: COLLECT (Nonius, 1998), DIRAX/LSQ (Duisenberg, 1992), EVALCCD (Duisenberg, 1998), SIR97 (Altomare et al., 1999), SHELXL97 (Sheldrick, 2008), DIAMOND (Brandenburg, 2005), WinGX (Farrugia, 1999).
Mn1—O1 | 2.2129 (10) | P1—H1 | 1.42 (5) |
Mn1—Mn2 | 2.9994 (4) | P2—O1 | 1.5311 (10) |
Mn2—O2 | 2.1186 (11) | P2—H2 | 1.32 (5) |
Mn2—O1 | 2.2766 (10) | O2—K1 | 2.8829 (9) |
P1—O2 | 1.5237 (10) | K1—O2i | 2.8740 (12) |
O1—Mn1—O1ii | 180.00 (5) | O2—Mn2—O1iv | 96.71 (3) |
O1—Mn1—O1iii | 98.38 (4) | O1—Mn2—O1iv | 78.87 (4) |
O1ii—Mn1—O1iii | 81.62 (4) | O2vi—P1—O2 | 111.57 (4) |
Mn2ii—Mn1—Mn2 | 180 | O2—P1—H1 | 107.28 (5) |
O2—Mn2—O2iv | 87.45 (4) | O1vii—P2—O1 | 113.21 (4) |
O2—Mn2—O1v | 174.23 (4) | O1—P2—H2 | 105.41 (4) |
Symmetry codes: (i) y+2/3, −x+y+1/3, −z+1/3; (ii) −x, −y, −z; (iii) y, −x+y, −z; (iv) −y, x−y, z; (v) −x+y, −x, z; (vi) −x+y, −x+1, z; (vii) −x+y+1, −x+1, z. |
After the discovery of microporous aluminophosphates, considerable efforts have been directed towards the synthesis of new open-framework transition metal phosphates because of their potential applications in catalysis, adsorption, ionic conduction, ion exchange, magnetism and electronics (Cheetham et al., 1999). The phosphate group, (PO4)3-, has historically been one of the most productive oxoanions for obtaining new structures. The replacement of phosphate by phosphite in transition metal phosphates has attracted more and more research effort, notably since the synthesis of the first organically templated vanadium phosphite with an open framework (Bonavia et al., 1995). In the phosphite group, (HPO3)2-, the P atom remains in a low oxidation state of +3 and the group has trigonal–pyramidal geometry, which provides versatility in allowing it to build either open or condensed frameworks.
In recent years, the family of transition metal phosphites has grown rapidly and numerous compounds with interesting structure diversity, such as V (Fu et al., 2006), Fe (Chung et al., 2006), Co (Li et al., 2008) and Zn (Johnstone & Harrison, 2004) phosphites, have been reported. However, few phosphite compounds with the MnII cation are known (Attfield et al., 1994; Fernandez et al., 2000, 2001; Chung et al., 2005). In order to extend knowledge of phosphite materials incorporating metallic magnetic cations belonging to the first series of the transition elements, particularly in the presence of a second metal atom, this work focused on the alkali metal–manganese–phosphite acid system. In this context we obtained the title compound using hydrothermal treatment and autogenous pressure.
The structure of K2[Mn3(HPO3)4] consists of a two-dimensional framework formed by MnO6 octahedra and (HPO3)2- pseudo tetrahedra. As shown in Fig. 1, there are two crystallographically independent Mn and P atoms in the asymmetric unit, leading to two different octahedra and trigonal pyramids, respectively. The connection of the Mn octahedra by face-sharing forms an Mn3O12 linear trimer unit, where atom Mn1 is located at the centre and atom Mn2 in the extremes. The M–O distances for the Mn1O6 octahedron have identical values and the trans O—Mn1—O angles are 180°, due to the special position occupied by the Mn1 ions. In the Mn2O6 octahedron, the mean Mn2—O bond distance is 2.1976 (11) Å and the trans O—Mn2—O angles deviate from the ideal value by approximatively 6°. Finally, the cis and trans O—Mn—O angles in the MnO6 unit indicate a topology near octahedral. In the [HPO3]2- trigonal pyramids, the P—O and H—P bonds present mean values of 1.5274 (10) and 1.37 (5) Å, respectively. The two independent phosphite groups link the trimeric entities through the O atoms, leading to layers which propagate in the ab plane (Fig. 2a).
This association of polyhedra leads to a layered structure formed by anionic sheets of formula [Mn3(HPO3)4]2- stacked along the c axis, with an interlamellar distance estimated at 3.3 Å (Fig. 2b). While this anionic framework is known (Fernandez et al., 2000, 2001), the title compound is the first example with an alkaline metal as the cation. The K+ cations are located between the layers, compensating their negative charge, and are in ninefold coordination sites with interactions to three nearest-neighbour O atoms from one layer and six others farther from another layer (Fig. 3). The coordination environment adopted by the K+ cation is supported by bond-valence sum (BVS) calculations (Brown & Altermatt, 1985), which give a value of 1.19 v.u. for K. The mean K—O bond distance of 2.880 (1) Å is near the values reported for K2Co(HPO3)2.2H2O [2.789 (2) Å; Ouarsal et al., 2004] and K2Zn3(HPO3)4 [2.861 (7) Å; Ortiz-Avila et al., 1989].
The formation of the manganese(II) phosphite indicates the reduction of this metal during the reaction. The oxidation state of the Mn in the title compound was verified using BVS calculations, which give oxidation states of 1.91 and 2.04 v.u. for Mn1 and Mn2, respectively. These results are in a good agreement with the expected values for this element considering the K2[Mn3(HPO3)4] chemical formula, and confirm the results obtained from the X-ray single-crystal structure determination.
The two phosphites, (C2H10N2)[Mn3(HPO3)4] (Fernandez et al., 2000) and (C3H12N2)[Mn3(HPO3)4] (Fernandez et al., 2001), showing the same layered architecture exhibited by the title compound, crystallize in the triclinic P1 and monoclinic C2/m space groups, respectively. It is noteworthy that in both compounds the absence of the threefold axis, due to the geometry of the intercalated cations located in the interlayer space, leads to lower symmetries compared with the trigonal symmetry obtained with the presence of the K+ cations in the structure. The Mn—O and P—O bond lengths and angles observed in K2[Mn3(HPO3)4] are similar to those recorded for the two previous manganese(II) phosphites. Finally, the effect of the nature of the intercalated entities on the interlayer distance is obvious and was expected. In fact, the interlayer distance is ca 3.3 Å for the potassium compound, while it is ca 5.5 and ca 6 Å for the ethylenediammonium and propanediammonium phases, respectively.