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The structure of the hydro­thermally synthesized compound AgCo3PO4(HPO4)2, silver tricobalt phosphate bis­(hydrogen phosphate), consists of edge-sharing CoO6 chains linked together by the phosphate groups and hydrogen bonds. The three-dimensional framework delimits two types of tunnels which accommodate Ag+ cations and OH groups. The title compound is isostructural with the compounds AM3H2(XO4)3 (A = Na or Ag, M = Co or Mn, and X = P or As) of the alluaudite structure type.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270101017759/br1345sup1.cif
Contains datablocks I, global

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270101017759/br1345Isup2.hkl
Contains datablock I

Comment top

The A—Co—X—O systems (A is a monovalent cation and X is P or As) have been investigated as part of a search for new materials which can exhibit interesting properties in relation to their structures (magnetism, ion exchange, ionic conductivity, etc.) In recent studies of the Na—Co—P—O system, we described the structure of Na2Co(H2PO4)4·4H2O synthesized at room temperature (Guesmi et al., 2000). In the present study, we have investigated the Ag—Co—P—O system by the hydrothermal method and we obtained the title compound, the structure of which is presented here.

AgCo3PO4(HPO4)2 crystallizes in the monoclinic space group C2/c and is isostructural with the AM3H2(XO4)3-type compounds (A is Na or Ag, M is a metal and X is P or As) of the alluaudite structure type (Keller et al., 1981; Lii & Shih, 1994; Leroux et al., 1995). The P and Co atoms are surrounded by four and six O atoms, respectively. The mean distances are Co1—O 2.108, Co2—O 2.158, P1—O 1.551 and P2—O 1.552 Å, and these are in the same range as in the isostructural cobalt compounds; the longer distances, P1—O and Co2—O, involve the O atom of the OH group. The bond valence sums of the Ag, Co and P atoms are in good agreement with their oxidation states (Brese & O'Keeffe, 1985).

The structure consists of infinite chains of edge-sharing CoO6 octahedra running along [101] and having a Co1—Co1—Co2 period. These chains are linked together by the phosphate groups to form polyhedral sheets parallel to the (101) plane (Fig. 1). Each P2O4 tetrahedron shares its four vertices with two chains of the same sheet. Adjacent sheets are interconnected by the tricoordinate O5 vertex common to two Co1O6 octahedra and the HP1O4 tetrahedron.

The three-dimensional framework delimits two types of hexagonal tunnels running along the c direction, at 0,0,z and 1/2,0,z (Fig. 2). The OH groups, pointing into one type of tunnel, are involved in strong hydrogen bonds (Brown, 1976). Square plane coordinated Ag+ cations are located in the second type of tunnel. The same coordination for this cation is found in the homologous arsenates (Keller et al., 1981).

Experimental top

Single crystals of AgCo3PO4(HPO4)2 were prepared hydrothermally from an aqueous solution of AgNO3 (Fluka, 99%), Co(NO3)2·6H2O (Fluka, 99%) and H3PO4 (Prolabo, 85%, density 1.70 Mg m-3), with the atomic ratio Ag:Co:P = 2:1:2. The mixture was filled in a glass tube to about 25% in volume. The tube was sealed and heated to 573 K for 3 d. Normal cooling to room temperature produced pink parallelepiped crystals of AgCo3PO4(HPO4)2.

Refinement top

The position of the H atom was obtained by difference techniques and the O6—H bond length was restrained to 0.80 Å by the DFIX option in SHELXL97 (Sheldrick, 1997). BUT s.u. given in Table 2 - please clarify.

Computing details top

Data collection: CAD-4 EXPRESS (Duisenberg, 1992; Macíček & Yordanov, 1992); cell refinement: CAD-4 EXPRESS; data reduction: MolEN (Fair, 1990); program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: DIAMOND (Brandenburg, 1998); software used to prepare material for publication: SHELXL97.

Figures top
[Figure 1] Fig. 1. A view of a sheet of the anionic framework of AgCo3PO4(HPO4)2 with 50% probability displacement ellipsoids.
[Figure 2] Fig. 2. A projection of the structure of AgCo3PO4(HPO4)2 along [001].
Silver tricobalt phosphate bis(hydrogen phosphate) top
Crystal data top
AgCo3PO4(HPO4)2F(000) = 1084
Mr = 571.59Dx = 4.320 Mg m3
Monoclinic, C2/cMo Kα radiation, λ = 0.71069 Å
a = 12.035 (2) ÅCell parameters from 25 reflections
b = 12.235 (2) Åθ = 10.8–13.8°
c = 6.541 (2) ŵ = 8.38 mm1
β = 114.14 (2)°T = 293 K
V = 878.9 (3) Å3Parallelepiped, pink
Z = 40.43 × 0.18 × 0.14 mm
Data collection top
Enraf-Nonius CAD4
diffractometer
932 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tubeRint = 0.013
Graphite monochromatorθmax = 27.0°, θmin = 2.5°
ω/2θ scansh = 1415
Absorption correction: ψ-scan
(North et al., 1968)
k = 150
Tmin = 0.178, Tmax = 0.309l = 80
1048 measured reflections2 standard reflections every 120 min
961 independent reflections intensity decay: 0.4%
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.025H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.068 w = 1/[σ2(Fo2) + (0.0351P)2 + 5.6691P]
where P = (Fo2 + 2Fc2)/3
S = 1.22(Δ/σ)max < 0.001
961 reflectionsΔρmax = 0.97 e Å3
92 parametersΔρmin = 1.46 e Å3
0 restraintsExtinction correction: SHELXL97 (Sheldrick, 1997), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.0184 (7)
Crystal data top
AgCo3PO4(HPO4)2V = 878.9 (3) Å3
Mr = 571.59Z = 4
Monoclinic, C2/cMo Kα radiation
a = 12.035 (2) ŵ = 8.38 mm1
b = 12.235 (2) ÅT = 293 K
c = 6.541 (2) Å0.43 × 0.18 × 0.14 mm
β = 114.14 (2)°
Data collection top
Enraf-Nonius CAD4
diffractometer
932 reflections with I > 2σ(I)
Absorption correction: ψ-scan
(North et al., 1968)
Rint = 0.013
Tmin = 0.178, Tmax = 0.3092 standard reflections every 120 min
1048 measured reflections intensity decay: 0.4%
961 independent reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0250 restraints
wR(F2) = 0.068H atoms treated by a mixture of independent and constrained refinement
S = 1.22Δρmax = 0.97 e Å3
961 reflectionsΔρmin = 1.46 e Å3
92 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.

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 (Å2) top
xyzUiso*/Ueq
Ag0.00000.47148 (4)0.25000.02258 (19)
Co10.29015 (4)0.16196 (4)0.37801 (8)0.00841 (18)
Co20.50000.27873 (5)0.25000.0094 (2)
P10.22255 (8)0.38696 (7)0.11416 (14)0.0072 (2)
P20.00000.18372 (10)0.25000.0073 (3)
O10.1068 (2)0.1078 (2)0.2663 (4)0.0108 (5)
O20.0350 (2)0.2557 (2)0.4620 (4)0.0092 (5)
O30.3443 (2)0.1719 (2)0.1121 (4)0.0093 (5)
O40.2169 (2)0.31838 (19)0.3066 (4)0.0090 (5)
O50.1628 (2)0.4994 (2)0.1069 (4)0.0111 (5)
O60.3605 (2)0.4057 (2)0.1588 (4)0.0105 (5)
H0.384 (6)0.467 (2)0.193 (12)0.050*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Ag0.0098 (2)0.0393 (3)0.0152 (3)0.0000.00155 (18)0.000
Co10.0084 (3)0.0060 (3)0.0109 (3)0.00012 (16)0.0040 (2)0.00024 (16)
Co20.0086 (3)0.0086 (3)0.0109 (3)0.0000.0040 (3)0.000
P10.0076 (4)0.0046 (4)0.0088 (4)0.0001 (3)0.0027 (3)0.0003 (3)
P20.0057 (5)0.0058 (5)0.0086 (6)0.0000.0011 (4)0.000
O10.0081 (11)0.0069 (11)0.0171 (13)0.0008 (9)0.0048 (10)0.0009 (9)
O20.0072 (11)0.0098 (11)0.0092 (11)0.0010 (9)0.0020 (9)0.0010 (9)
O30.0092 (11)0.0093 (11)0.0083 (11)0.0014 (9)0.0025 (9)0.0006 (8)
O40.0100 (11)0.0076 (11)0.0097 (11)0.0002 (9)0.0045 (9)0.0006 (9)
O50.0100 (11)0.0057 (10)0.0168 (13)0.0012 (9)0.0045 (10)0.0005 (9)
O60.0078 (11)0.0067 (11)0.0160 (12)0.0015 (9)0.0039 (9)0.0008 (9)
Geometric parameters (Å, º) top
Ag—O5i2.382 (3)Co2—O32.156 (2)
Ag—O5ii2.382 (3)Co2—O3vii2.156 (2)
Ag—O52.516 (3)Co2—O6vii2.184 (3)
Ag—O5iii2.516 (3)Co2—O62.184 (3)
Co1—O5iv2.059 (3)P1—O41.537 (2)
Co1—O42.079 (2)P1—O3viii1.543 (3)
Co1—O32.096 (3)P1—O51.544 (3)
Co1—O4v2.113 (2)P1—O61.581 (3)
Co1—O12.126 (2)P2—O21.549 (3)
Co1—O2v2.176 (2)P2—O2iii1.549 (3)
Co2—O2v2.134 (2)P2—O1iii1.554 (2)
Co2—O2vi2.134 (2)P2—O11.554 (2)
O5i—Ag—O5ii162.80 (12)O2v—Co2—O3vii87.85 (9)
O5i—Ag—O583.73 (8)O2vi—Co2—O3vii78.36 (9)
O5ii—Ag—O593.94 (8)O3—Co2—O3vii105.36 (13)
O5i—Ag—O5iii93.94 (8)O2v—Co2—O6vii107.85 (10)
O5ii—Ag—O5iii83.73 (8)O2vi—Co2—O6vii88.53 (10)
O5—Ag—O5iii164.39 (12)O3—Co2—O6vii170.02 (9)
O5iv—Co1—O4169.42 (10)O3vii—Co2—O6vii82.99 (9)
O5iv—Co1—O385.57 (10)O2v—Co2—O688.53 (10)
O4—Co1—O390.43 (10)O2vi—Co2—O6107.85 (10)
O5iv—Co1—O4v100.56 (10)O3—Co2—O682.99 (9)
O4—Co1—O4v86.10 (10)O3vii—Co2—O6170.02 (9)
O3—Co1—O4v162.56 (10)O6vii—Co2—O689.27 (13)
O5iv—Co1—O186.66 (10)O4—P1—O3viii110.50 (14)
O4—Co1—O185.68 (9)O4—P1—O5109.60 (14)
O3—Co1—O1111.36 (10)O3viii—P1—O5109.41 (14)
O4v—Co1—O185.45 (10)O4—P1—O6108.84 (14)
O5iv—Co1—O2v103.38 (10)O3viii—P1—O6109.97 (14)
O4—Co1—O2v85.38 (10)O5—P1—O6108.49 (14)
O3—Co1—O2v78.72 (10)O2—P2—O2iii110.7 (2)
O4v—Co1—O2v83.96 (9)O2—P2—O1iii108.41 (13)
O1—Co1—O2v166.57 (10)O2iii—P2—O1iii111.33 (13)
O2v—Co2—O2vi157.24 (14)O2—P2—O1111.33 (13)
O2v—Co2—O378.36 (9)O2iii—P2—O1108.41 (13)
O2vi—Co2—O387.85 (9)O1iii—P2—O1106.59 (19)
Symmetry codes: (i) x, y+1, z+1/2; (ii) x, y+1, z; (iii) x, y, z+1/2; (iv) x+1/2, y1/2, z+1/2; (v) x+1/2, y+1/2, z+1; (vi) x+1/2, y+1/2, z1/2; (vii) x+1, y, z+1/2; (viii) x+1/2, y+1/2, z.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O6—H···O1ix0.80 (3)1.74 (3)2.520 (3)164 (8)
Symmetry code: (ix) x+1/2, y+1/2, z+1/2.

Experimental details

Crystal data
Chemical formulaAgCo3PO4(HPO4)2
Mr571.59
Crystal system, space groupMonoclinic, C2/c
Temperature (K)293
a, b, c (Å)12.035 (2), 12.235 (2), 6.541 (2)
β (°) 114.14 (2)
V3)878.9 (3)
Z4
Radiation typeMo Kα
µ (mm1)8.38
Crystal size (mm)0.43 × 0.18 × 0.14
Data collection
DiffractometerEnraf-Nonius CAD4
diffractometer
Absorption correctionψ-scan
(North et al., 1968)
Tmin, Tmax0.178, 0.309
No. of measured, independent and
observed [I > 2σ(I)] reflections
1048, 961, 932
Rint0.013
(sin θ/λ)max1)0.638
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.025, 0.068, 1.22
No. of reflections961
No. of parameters92
H-atom treatmentH atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å3)0.97, 1.46

Computer programs: CAD-4 EXPRESS (Duisenberg, 1992; Macíček & Yordanov, 1992), CAD-4 EXPRESS, MolEN (Fair, 1990), SHELXS97 (Sheldrick, 1990), SHELXL97 (Sheldrick, 1997), DIAMOND (Brandenburg, 1998), SHELXL97.

Selected bond lengths (Å) top
Ag—O5i2.382 (3)Co2—O32.156 (2)
Ag—O5ii2.382 (3)Co2—O3vii2.156 (2)
Ag—O52.516 (3)Co2—O6vii2.184 (3)
Ag—O5iii2.516 (3)Co2—O62.184 (3)
Co1—O5iv2.059 (3)P1—O41.537 (2)
Co1—O42.079 (2)P1—O3viii1.543 (3)
Co1—O32.096 (3)P1—O51.544 (3)
Co1—O4v2.113 (2)P1—O61.581 (3)
Co1—O12.126 (2)P2—O21.549 (3)
Co1—O2v2.176 (2)P2—O2iii1.549 (3)
Co2—O2v2.134 (2)P2—O1iii1.554 (2)
Co2—O2vi2.134 (2)P2—O11.554 (2)
Symmetry codes: (i) x, y+1, z+1/2; (ii) x, y+1, z; (iii) x, y, z+1/2; (iv) x+1/2, y1/2, z+1/2; (v) x+1/2, y+1/2, z+1; (vi) x+1/2, y+1/2, z1/2; (vii) x+1, y, z+1/2; (viii) x+1/2, y+1/2, z.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O6—H···O1ix0.80 (3)1.74 (3)2.520 (3)164 (8)
Symmetry code: (ix) x+1/2, y+1/2, z+1/2.
 

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