Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270105037236/ta1500sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270105037236/ta1500Isup2.hkl |
The title compound was synthesized under hydrothermal conditions. The starting material was prepared by mixing NaH2PO4·H2O, MnO and Al2O3 in the appropriate proportions. An H3PO4 solution was added in order to achieve stoichiometry, and the mixture was homogenized in a mortar after evaporation. About 25 mg of the resulting residue was sealed into a gold tube with an outer diameter of 2 mm and a length of 25 mm, containing 2 mg of distilled water. The gold capsule was then inserted in a Tuttle-type pressure vessel (Tuttle, 1949) and maintained at a temperature of 1073 K and a pressure of 0.1 GPa. After 7 d, the sample, still in the gold tube in the autoclave, was quenched to room temperature in a stream of cold air. The synthesized compounds consisted of colourless needles of the title alluaudite-type compound, associated with irregular colourless crystals of Na3Al2(PO4)3 and with an amorphous matrix. Chemical analysis of the title compound was carried out with a CAMEBAX SX-50 electron microprobe (15 kV acceleration voltage, 20 nA beam current). The standards used were graftonite from Kabira (sample KF16; Fransolet, 1975) (Mn, P), oligoclase (Na) and corundum (Al). The average of six point analyses gives P2O5 45.33, Al2O3 8.27, MnO 37.53 and Na2O 9.46, total 100.59 wt.%. The chemical composition, calculated on the basis of 12 O, corresponds to Na1.453Mn2.518Al0.772(P1.01O4)3.
Atomic coordinates similar to those given by Moore (1971) and by Hatert et al. (2000) were used during the refinement procedure. The site-occupancy factors indicated, in the early stages of the refinement, that the M2 site was occupied by Al3+ and Mn2+ ions, and that A1 was occupied by Mn2+ and Na+ ions. Consequently, the site-occupancy factors of both atoms were refined simultaneously on each site, and the sums of the site-occupancy factors were constrained to 1.0. The positions of these atoms and their temperature factors were constrained to be identical with the EXYZ and EADP instructions of SHELXL97 (Sheldrick, 1997).
In the natural geological environment of granitic pegmatites, alluaudite-type phosphates generally show chemical compositions comprised between Na2MnFe2+Fe3+(PO4)3 and NaMnFe3+2(PO4)3. The incorporation of significant amounts of aluminium into the crystal structure of these minerals produces a splitting of the M2 site of alluaudite into the M2a and M2b positions, thus leading to the more ordered wyllieite-type phosphates (Moore & Molin-Case, 1974; Hatert, Lefèvre et al., 2005). Consequently, the C2/c space group of alluaudite transforms into P21/n in wyllieite, with no significant change in the unit-cell parameters.
During the past 20 years, numerous alluaudite-type phosphates have been synthesized, and the crystal chemistry of this structure type is now well known (Hatert, 2004; Hatert, Rebbouh et al., 2005). Nevertheless, the structural descriptions of natural or synthetic wyllieite-type phosphates are rather scarce (Moore & Molin-Case, 1974; Zhesheng et al., 1983; Brier, 2000; Hatert, Lefèvre et al., 2005). In order to understand better the crystal chemistry of wyllieite-type phosphates, we attempted to obtain a single-crystal of wyllieite by hydrothermal synthesis at 1073 K and 0.1 GPa, starting from the composition Na2Mn2Al(PO4)3 (Hatert, 2002). The synthesized crystals were investigated by single-crystal X-ray diffraction techniques, and a careful examination of systematic absences indicated the C2/c space group, characteristic of alluaudite-type phosphates. The crystal structure of this Al-rich alluaudite-type compound is reported here.
The structure is similar to that of natural alluaudite, described by Moore (1971), and consists of kinked chains of edge-sharing octahedra stacked parallel to {101}. These chains are formed by a succession of M2–M2 octahedral pairs, linked by highly distorted M1 octahedra (Fig. 1). Equivalent chains are connected in the b direction by the P1 and P2 phosphate tetrahedra to form sheets oriented perpendicular to [010] (Fig. 2). These interconnected chains produce channels parallel to c, which contain the large distorted cubic A1 site and the A2' site with a morphology of a gabled disphenoid (Fig. 2). The site-occupancy factors indicate the following cationic distribution: 0.891 (10) Na+ in A2', 0.619 (8) Na+ + 0.381 (7) Mn2+ in A1, 0.908 (4) Mn2+ in M1, and 0.573 (6) Mn2+ + 0.427 (6) A l3+ in M2. This cationic distribution is in very good agreement with the chemical composition.
Bond-valence sums were calculated for each ion using the parameters of Brown & Altermatt (1985). The P1 and P2 bond-valence sums are 4.99 and 4.98, respectively, and the O-atom bond-valence sums are within the normal acceptable range (1.89–2.10). For the M1 site, the low bond-valence sum obtained in the preliminary calculations indicates an occupancy by ca 0.150 Na+ + 0.850 Mn2+.
Data collection: XSCANS in SHELXTL-Plus (Sheldrick, 1991); cell refinement: XSCANS; data reduction: SHELXTL-Plus; program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ATOMS (Dowty, 1993); software used to prepare material for publication: SHELXTL-Plus.
Na1.50Mn2.48Al0.85(PO4)3 | F(000) = 922 |
Mr = 468.76 | Dx = 3.614 Mg m−3 |
Monoclinic, C2/c | Mo Kα radiation, λ = 0.71073 Å |
a = 11.9816 (10) Å | Cell parameters from 34 reflections |
b = 12.5387 (13) Å | θ = 5.8–12.5° |
c = 6.4407 (10) Å | µ = 4.31 mm−1 |
β = 114.621 (8)° | T = 293 K |
V = 879.64 (18) Å3 | Acicular, elongated along the c axis, colourless |
Z = 4 | 0.23 × 0.07 × 0.05 mm |
Bruker P4 diffractometer | 894 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube, Bruker P4 | Rint = 0.024 |
Graphite monochromator | θmax = 27.5°, θmin = 2.5° |
Profile data from ω scans | h = −15→1 |
Absorption correction: ψ scan XSCANS in SHELXTL-Plus (Sheldrick, 1991) | k = −16→1 |
Tmin = 0.761, Tmax = 0.806 | l = −7→8 |
1271 measured reflections | 3 standard reflections every 97 reflections |
1019 independent reflections | intensity decay: 2.3% |
Refinement on F2 | 2 restraints |
Least-squares matrix: full | Primary atom site location: structure-invariant direct methods |
R[F2 > 2σ(F2)] = 0.032 | Secondary atom site location: difference Fourier map |
wR(F2) = 0.075 | w = 1/[σ2(Fo2) + (0.0344P)2 + 2.4705P] where P = (Fo2 + 2Fc2)/3 |
S = 1.07 | (Δ/σ)max < 0.001 |
1019 reflections | Δρmax = 0.52 e Å−3 |
100 parameters | Δρmin = −0.65 e Å−3 |
Na1.50Mn2.48Al0.85(PO4)3 | V = 879.64 (18) Å3 |
Mr = 468.76 | Z = 4 |
Monoclinic, C2/c | Mo Kα radiation |
a = 11.9816 (10) Å | µ = 4.31 mm−1 |
b = 12.5387 (13) Å | T = 293 K |
c = 6.4407 (10) Å | 0.23 × 0.07 × 0.05 mm |
β = 114.621 (8)° |
Bruker P4 diffractometer | 894 reflections with I > 2σ(I) |
Absorption correction: ψ scan XSCANS in SHELXTL-Plus (Sheldrick, 1991) | Rint = 0.024 |
Tmin = 0.761, Tmax = 0.806 | 3 standard reflections every 97 reflections |
1271 measured reflections | intensity decay: 2.3% |
1019 independent reflections |
R[F2 > 2σ(F2)] = 0.032 | 100 parameters |
wR(F2) = 0.075 | 2 restraints |
S = 1.07 | Δρmax = 0.52 e Å−3 |
1019 reflections | Δρmin = −0.65 e Å−3 |
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. |
x | y | z | Uiso*/Ueq | Occ. (<1) | |
Na1 | 0.5000 | 0.0000 | 0.0000 | 0.0268 (5) | 0.619 (8) |
Mn1 | 0.5000 | 0.0000 | 0.0000 | 0.0268 (5) | 0.381 (7) |
Na2 | 0.0000 | −0.0207 (2) | 0.2500 | 0.0329 (9) | 0.891 (10) |
Mn3 | 0.0000 | 0.26627 (6) | 0.2500 | 0.0144 (3) | 0.908 (4) |
Mn4 | 0.27572 (5) | 0.65456 (5) | 0.35763 (10) | 0.0137 (2) | 0.573 (6) |
Al4 | 0.27572 (5) | 0.65456 (5) | 0.35763 (10) | 0.0137 (2) | 0.427 (6) |
P1 | 0.0000 | −0.28457 (9) | 0.2500 | 0.0158 (3) | |
P2 | 0.23711 (7) | −0.10611 (7) | 0.13087 (13) | 0.0154 (2) | |
O1 | 0.4524 (2) | 0.71353 (19) | 0.5356 (4) | 0.0183 (5) | |
O2 | 0.0959 (3) | 0.6397 (2) | 0.2321 (5) | 0.0422 (9) | |
O3 | 0.3317 (3) | 0.6633 (2) | 0.0992 (4) | 0.0290 (7) | |
O4 | 0.1268 (2) | 0.4078 (2) | 0.3175 (5) | 0.0266 (6) | |
O5 | 0.2279 (2) | 0.8255 (2) | 0.3217 (4) | 0.0282 (6) | |
O6 | 0.3272 (3) | 0.5010 (2) | 0.3849 (5) | 0.0291 (6) |
U11 | U22 | U33 | U12 | U13 | U23 | |
Na1 | 0.0365 (9) | 0.0114 (7) | 0.0133 (7) | 0.0006 (5) | −0.0087 (5) | 0.0001 (4) |
Mn1 | 0.0365 (9) | 0.0114 (7) | 0.0133 (7) | 0.0006 (5) | −0.0087 (5) | 0.0001 (4) |
Na2 | 0.0203 (13) | 0.0427 (17) | 0.0256 (14) | 0.000 | −0.0004 (10) | 0.000 |
Mn3 | 0.0138 (4) | 0.0111 (4) | 0.0198 (4) | 0.000 | 0.0085 (3) | 0.000 |
Mn4 | 0.0114 (3) | 0.0172 (3) | 0.0119 (3) | 0.0032 (2) | 0.0043 (2) | −0.0002 (2) |
Al4 | 0.0114 (3) | 0.0172 (3) | 0.0119 (3) | 0.0032 (2) | 0.0043 (2) | −0.0002 (2) |
P1 | 0.0201 (6) | 0.0129 (5) | 0.0087 (5) | 0.000 | 0.0005 (4) | 0.000 |
P2 | 0.0124 (4) | 0.0194 (4) | 0.0104 (4) | 0.0005 (3) | 0.0007 (3) | −0.0044 (3) |
O1 | 0.0181 (11) | 0.0202 (12) | 0.0129 (10) | 0.0059 (10) | 0.0028 (9) | −0.0034 (9) |
O2 | 0.051 (2) | 0.0318 (16) | 0.0305 (16) | 0.0162 (14) | 0.0036 (15) | −0.0178 (13) |
O3 | 0.0380 (16) | 0.0233 (14) | 0.0157 (12) | −0.0103 (12) | 0.0011 (11) | −0.0062 (10) |
O4 | 0.0155 (12) | 0.0193 (12) | 0.0413 (16) | 0.0034 (10) | 0.0083 (11) | 0.0074 (11) |
O5 | 0.0226 (13) | 0.0408 (16) | 0.0183 (13) | 0.0028 (12) | 0.0056 (10) | 0.0036 (11) |
O6 | 0.0230 (14) | 0.0337 (15) | 0.0218 (13) | −0.0123 (12) | 0.0006 (10) | 0.0083 (11) |
Na1—O2i | 2.278 (3) | Mn4—O5 | 2.206 (3) |
Na1—O2ii | 2.278 (3) | Mn4—Mn4xvii | 3.2268 (12) |
Na1—O4i | 2.288 (2) | Mn4—Na2ix | 3.2814 (16) |
Na1—O4ii | 2.288 (2) | Mn4—Na1xvi | 3.6925 (7) |
Na1—O4iii | 2.552 (3) | P1—O2xviii | 1.531 (3) |
Na1—O4iv | 2.552 (3) | P1—O2xix | 1.531 (3) |
Na1—O2iii | 3.003 (4) | P1—O1ix | 1.539 (2) |
Na1—O2iv | 3.003 (4) | P1—O1x | 1.539 (2) |
Na1—P1v | 3.1447 (10) | P1—Na1xi | 3.1447 (10) |
Na1—P1vi | 3.1447 (10) | P1—Na1iv | 3.1447 (10) |
Na1—Mn1vii | 3.2204 (5) | P2—O6iv | 1.531 (3) |
Na1—Mn1viii | 3.2204 (5) | P2—O4iv | 1.533 (3) |
Na2—O6ix | 2.413 (3) | P2—O5xix | 1.540 (3) |
Na2—O6x | 2.413 (3) | P2—O3i | 1.540 (2) |
Na2—O6iv | 2.572 (3) | P2—Na2xiii | 3.2877 (16) |
Na2—O6xi | 2.572 (3) | P2—Na1viii | 3.3323 (9) |
Na2—O1x | 2.725 (3) | O1—P1ix | 1.539 (2) |
Na2—O1ix | 2.725 (3) | O1—Mn3vi | 2.241 (2) |
Na2—O3iv | 2.949 (4) | O1—Na2ix | 2.725 (3) |
Na2—O3xi | 2.949 (4) | O2—P1xx | 1.531 (3) |
Na2—Na2xii | 3.2618 (10) | O2—Na1xvi | 2.278 (3) |
Na2—Na2xiii | 3.2618 (10) | O2—Mn1xvi | 2.278 (3) |
Na2—Mn4x | 3.2814 (16) | O2—Na1xv | 3.003 (4) |
Na2—Al4x | 3.2814 (16) | O3—P2i | 1.540 (2) |
Mn3—O1xi | 2.241 (2) | O3—Mn3vi | 2.246 (3) |
Mn3—O1iv | 2.241 (2) | O3—Na2vi | 2.949 (4) |
Mn3—O3xi | 2.246 (3) | O4—P2xv | 1.533 (3) |
Mn3—O3iv | 2.246 (3) | O4—Na1xvi | 2.288 (2) |
Mn3—O4 | 2.257 (3) | O4—Mn1xvi | 2.288 (2) |
Mn3—O4xiv | 2.257 (3) | O4—Na1xv | 2.552 (3) |
Mn3—Na1xv | 3.3439 (7) | O5—P2xx | 1.540 (3) |
Mn3—Na1xvi | 3.3439 (7) | O5—Al4xvii | 2.098 (3) |
Mn4—O2 | 1.970 (3) | O5—Mn4xvii | 2.098 (3) |
Mn4—O6 | 2.007 (3) | O6—P2xv | 1.531 (3) |
Mn4—O3 | 2.041 (3) | O6—Na2ix | 2.413 (3) |
Mn4—O1 | 2.078 (2) | O6—Na2vi | 2.572 (3) |
Mn4—O5xvii | 2.098 (3) | ||
O2i—Na1—O2ii | 180.00 (15) | O3iv—Mn3—O4xiv | 161.10 (9) |
O2i—Na1—O4i | 80.59 (10) | O4—Mn3—O4xiv | 76.32 (13) |
O2ii—Na1—O4i | 99.41 (10) | O1xi—Mn3—Na1xv | 79.18 (6) |
O2i—Na1—O4ii | 99.41 (10) | O1iv—Mn3—Na1xv | 134.83 (6) |
O2ii—Na1—O4ii | 80.59 (10) | O3xi—Mn3—Na1xv | 122.15 (7) |
O4i—Na1—O4ii | 180.00 (11) | O3iv—Mn3—Na1xv | 118.42 (7) |
O2i—Na1—O4iii | 106.26 (11) | O4—Mn3—Na1xv | 49.69 (7) |
O2ii—Na1—O4iii | 73.74 (11) | O4xiv—Mn3—Na1xv | 43.00 (6) |
O4i—Na1—O4iii | 70.15 (10) | O1xi—Mn3—Na1xvi | 134.83 (6) |
O4ii—Na1—O4iii | 109.85 (10) | O1iv—Mn3—Na1xvi | 79.18 (6) |
O2i—Na1—O4iv | 73.74 (11) | O3xi—Mn3—Na1xvi | 118.42 (7) |
O2ii—Na1—O4iv | 106.26 (11) | O3iv—Mn3—Na1xvi | 122.15 (7) |
O4i—Na1—O4iv | 109.85 (10) | O4—Mn3—Na1xvi | 43.00 (6) |
O4ii—Na1—O4iv | 70.15 (10) | O4xiv—Mn3—Na1xvi | 49.69 (7) |
O4iii—Na1—O4iv | 180.00 (12) | Na1xv—Mn3—Na1xvi | 57.571 (15) |
O2i—Na1—O2iii | 51.94 (13) | O1xi—Mn3—Na2 | 72.84 (6) |
O2ii—Na1—O2iii | 128.06 (13) | O1iv—Mn3—Na2 | 72.84 (6) |
O4i—Na1—O2iii | 92.95 (9) | O3xi—Mn3—Na2 | 54.89 (7) |
O4ii—Na1—O2iii | 87.05 (9) | O3iv—Mn3—Na2 | 54.89 (7) |
O4iii—Na1—O2iii | 63.63 (8) | O4—Mn3—Na2 | 141.84 (6) |
O4iv—Na1—O2iii | 116.37 (8) | O4xiv—Mn3—Na2 | 141.84 (6) |
O2i—Na1—O2iv | 128.06 (13) | Na1xv—Mn3—Na2 | 151.214 (8) |
O2ii—Na1—O2iv | 51.94 (13) | Na1xvi—Mn3—Na2 | 151.214 (8) |
O4i—Na1—O2iv | 87.05 (9) | O2—Mn4—O6 | 100.89 (12) |
O4ii—Na1—O2iv | 92.95 (9) | O2—Mn4—O3 | 110.21 (12) |
O4iii—Na1—O2iv | 116.37 (8) | O6—Mn4—O3 | 85.92 (11) |
O4iv—Na1—O2iv | 63.63 (8) | O2—Mn4—O1 | 161.56 (10) |
O2iii—Na1—O2iv | 180.00 (17) | O6—Mn4—O1 | 95.04 (10) |
O2i—Na1—P1v | 27.28 (8) | O3—Mn4—O1 | 79.95 (10) |
O2ii—Na1—P1v | 152.72 (8) | O2—Mn4—O5xvii | 87.01 (12) |
O4i—Na1—P1v | 96.77 (7) | O6—Mn4—O5xvii | 99.19 (11) |
O4ii—Na1—P1v | 83.23 (7) | O3—Mn4—O5xvii | 160.92 (11) |
O4iii—Na1—P1v | 91.50 (6) | O1—Mn4—O5xvii | 81.29 (10) |
O4iv—Na1—P1v | 88.50 (6) | O2—Mn4—O5 | 81.77 (11) |
O2iii—Na1—P1v | 28.73 (6) | O6—Mn4—O5 | 176.65 (11) |
O2iv—Na1—P1v | 151.27 (6) | O3—Mn4—O5 | 91.26 (10) |
O2i—Na1—P1vi | 152.72 (8) | O1—Mn4—O5 | 82.68 (10) |
O2ii—Na1—P1vi | 27.28 (8) | O5xvii—Mn4—O5 | 82.92 (11) |
O4i—Na1—P1vi | 83.23 (7) | O2—Mn4—Mn4xvii | 82.43 (8) |
O4ii—Na1—P1vi | 96.77 (7) | O6—Mn4—Mn4xvii | 141.85 (9) |
O4iii—Na1—P1vi | 88.50 (6) | O3—Mn4—Mn4xvii | 129.02 (8) |
O4iv—Na1—P1vi | 91.50 (6) | O1—Mn4—Mn4xvii | 79.30 (7) |
O2iii—Na1—P1vi | 151.27 (6) | O5xvii—Mn4—Mn4xvii | 42.73 (8) |
O2iv—Na1—P1vi | 28.73 (6) | O5—Mn4—Mn4xvii | 40.19 (7) |
P1v—Na1—P1vi | 180.0 | O2—Mn4—Na2ix | 132.26 (10) |
O2i—Na1—Mn1vii | 63.51 (9) | O6—Mn4—Na2ix | 47.05 (8) |
O2ii—Na1—Mn1vii | 116.49 (9) | O3—Mn4—Na2ix | 102.32 (8) |
O4i—Na1—Mn1vii | 51.89 (7) | O1—Mn4—Na2ix | 55.81 (8) |
O4ii—Na1—Mn1vii | 128.11 (7) | O5xvii—Mn4—Na2ix | 69.44 (8) |
O4iii—Na1—Mn1vii | 44.88 (6) | O5—Mn4—Na2ix | 132.19 (8) |
O4iv—Na1—Mn1vii | 135.12 (6) | Mn4xvii—Mn4—Na2ix | 103.34 (4) |
O2iii—Na1—Mn1vii | 42.77 (5) | O2—Mn4—Na1xvi | 32.10 (8) |
O2iv—Na1—Mn1vii | 137.23 (5) | O6—Mn4—Na1xvi | 73.35 (8) |
P1v—Na1—Mn1vii | 59.201 (12) | O3—Mn4—Na1xvi | 91.83 (7) |
P1vi—Na1—Mn1vii | 120.799 (12) | O1—Mn4—Na1xvi | 166.34 (7) |
O2i—Na1—Mn1viii | 116.49 (9) | O5xvii—Mn4—Na1xvi | 107.25 (8) |
O2ii—Na1—Mn1viii | 63.51 (9) | O5—Mn4—Na1xvi | 108.58 (7) |
O4i—Na1—Mn1viii | 128.11 (7) | Mn4xvii—Mn4—Na1xvi | 114.25 (3) |
O4ii—Na1—Mn1viii | 51.89 (7) | Na2ix—Mn4—Na1xvi | 116.40 (4) |
O4iii—Na1—Mn1viii | 135.12 (6) | O2xviii—P1—O2xix | 103.3 (3) |
O4iv—Na1—Mn1viii | 44.88 (6) | O2xviii—P1—O1ix | 107.51 (15) |
O2iii—Na1—Mn1viii | 137.23 (5) | O2xix—P1—O1ix | 114.65 (13) |
O2iv—Na1—Mn1viii | 42.77 (5) | O2xviii—P1—O1x | 114.65 (13) |
P1v—Na1—Mn1viii | 120.799 (12) | O2xix—P1—O1x | 107.51 (15) |
P1vi—Na1—Mn1viii | 59.201 (12) | O1ix—P1—O1x | 109.28 (19) |
Mn1vii—Na1—Mn1viii | 180.0 | O2xviii—P1—Na1xi | 70.48 (14) |
O6ix—Na2—O6x | 168.26 (19) | O2xix—P1—Na1xi | 43.00 (12) |
O6ix—Na2—O6iv | 80.43 (8) | O1ix—P1—Na1xi | 151.32 (9) |
O6x—Na2—O6iv | 98.32 (9) | O1x—P1—Na1xi | 96.71 (9) |
O6ix—Na2—O6xi | 98.32 (9) | O2xviii—P1—Na1iv | 43.00 (12) |
O6x—Na2—O6xi | 80.43 (8) | O2xix—P1—Na1iv | 70.48 (14) |
O6iv—Na2—O6xi | 167.88 (17) | O1ix—P1—Na1iv | 96.71 (9) |
O6ix—Na2—O1x | 119.89 (12) | O1x—P1—Na1iv | 151.32 (9) |
O6x—Na2—O1x | 71.53 (9) | Na1xi—P1—Na1iv | 61.60 (2) |
O6iv—Na2—O1x | 87.18 (9) | O2xviii—P1—Na2 | 128.33 (14) |
O6xi—Na2—O1x | 103.69 (10) | O2xix—P1—Na2 | 128.33 (14) |
O6ix—Na2—O1ix | 71.53 (9) | O1ix—P1—Na2 | 54.64 (9) |
O6x—Na2—O1ix | 119.89 (12) | O1x—P1—Na2 | 54.64 (9) |
O6iv—Na2—O1ix | 103.69 (10) | Na1xi—P1—Na2 | 149.201 (12) |
O6xi—Na2—O1ix | 87.18 (9) | Na1iv—P1—Na2 | 149.201 (12) |
O1x—Na2—O1ix | 54.87 (11) | O6iv—P2—O4iv | 112.03 (16) |
O6ix—Na2—O3iv | 53.67 (8) | O6iv—P2—O5xix | 109.85 (16) |
O6x—Na2—O3iv | 115.62 (12) | O4iv—P2—O5xix | 108.32 (15) |
O6iv—Na2—O3iv | 59.50 (9) | O6iv—P2—O3i | 106.95 (15) |
O6xi—Na2—O3iv | 110.02 (11) | O4iv—P2—O3i | 110.91 (16) |
O1x—Na2—O3iv | 146.22 (8) | O5xix—P2—O3i | 108.74 (15) |
O1ix—Na2—O3iv | 123.85 (7) | O6iv—P2—Na2xiii | 43.25 (11) |
O6ix—Na2—O3xi | 115.62 (12) | O4iv—P2—Na2xiii | 128.12 (12) |
O6x—Na2—O3xi | 53.67 (8) | O5xix—P2—Na2xiii | 122.51 (11) |
O6iv—Na2—O3xi | 110.02 (11) | O3i—P2—Na2xiii | 63.70 (11) |
O6xi—Na2—O3xi | 59.50 (9) | O6iv—P2—Na1viii | 89.83 (11) |
O1x—Na2—O3xi | 123.85 (7) | O4iv—P2—Na1viii | 36.44 (10) |
O1ix—Na2—O3xi | 146.22 (8) | O5xix—P2—Na1viii | 90.79 (10) |
O3iv—Na2—O3xi | 77.10 (12) | O3i—P2—Na1viii | 147.20 (12) |
O6ix—Na2—Na2xii | 51.27 (7) | Na2xiii—P2—Na1viii | 127.26 (5) |
O6x—Na2—Na2xii | 126.38 (8) | O6iv—P2—Na2 | 45.20 (13) |
O6iv—Na2—Na2xii | 130.38 (7) | O4iv—P2—Na2 | 145.73 (11) |
O6xi—Na2—Na2xii | 47.05 (6) | O5xix—P2—Na2 | 69.60 (11) |
O1x—Na2—Na2xii | 123.72 (13) | O3i—P2—Na2 | 101.55 (12) |
O1ix—Na2—Na2xii | 74.15 (8) | Na2xiii—P2—Na2 | 58.26 (2) |
O3iv—Na2—Na2xii | 80.31 (9) | Na1viii—P2—Na2 | 110.03 (3) |
O3xi—Na2—Na2xii | 85.39 (10) | P1ix—O1—Mn4 | 127.78 (14) |
O6ix—Na2—Na2xiii | 126.38 (8) | P1ix—O1—Mn3vi | 116.07 (14) |
O6x—Na2—Na2xiii | 51.27 (7) | Mn4—O1—Mn3vi | 101.62 (9) |
O6iv—Na2—Na2xiii | 47.05 (6) | P1ix—O1—Na2ix | 97.93 (11) |
O6xi—Na2—Na2xiii | 130.38 (7) | Mn4—O1—Na2ix | 85.07 (9) |
O1x—Na2—Na2xiii | 74.15 (8) | Mn3vi—O1—Na2ix | 127.35 (10) |
O1ix—Na2—Na2xiii | 123.72 (13) | P1xx—O2—Mn4 | 129.57 (18) |
O3iv—Na2—Na2xiii | 85.39 (10) | P1xx—O2—Na1xvi | 109.71 (17) |
O3xi—Na2—Na2xiii | 80.31 (9) | Mn4—O2—Na1xvi | 120.55 (13) |
Na2xii—Na2—Na2xiii | 161.71 (19) | P1xx—O2—Mn1xvi | 109.71 (17) |
O6ix—Na2—Mn4x | 153.88 (12) | Mn4—O2—Mn1xvi | 120.55 (13) |
O6x—Na2—Mn4x | 37.51 (7) | Na1xvi—O2—Mn1xvi | 0.0 |
O6iv—Na2—Mn4x | 108.07 (7) | P1xx—O2—Na1xv | 80.79 (15) |
O6xi—Na2—Mn4x | 78.34 (7) | Mn4—O2—Na1xv | 115.74 (13) |
O1x—Na2—Mn4x | 39.12 (5) | Na1xvi—O2—Na1xv | 73.72 (10) |
O1ix—Na2—Mn4x | 82.39 (8) | Mn1xvi—O2—Na1xv | 73.72 (10) |
O3iv—Na2—Mn4x | 151.88 (7) | P2i—O3—Mn4 | 122.26 (16) |
O3xi—Na2—Mn4x | 85.31 (5) | P2i—O3—Mn3vi | 135.09 (17) |
Na2xii—Na2—Mn4x | 120.32 (6) | Mn4—O3—Mn3vi | 102.65 (10) |
Na2xiii—Na2—Mn4x | 69.99 (4) | P2i—O3—Na2vi | 88.38 (12) |
O6ix—Na2—Al4x | 153.88 (12) | Mn4—O3—Na2vi | 95.83 (9) |
O6x—Na2—Al4x | 37.51 (7) | Mn3vi—O3—Na2vi | 86.56 (10) |
O6iv—Na2—Al4x | 108.07 (7) | P2xv—O4—Mn3 | 121.45 (14) |
O6xi—Na2—Al4x | 78.34 (7) | P2xv—O4—Na1xvi | 120.11 (15) |
O1x—Na2—Al4x | 39.12 (5) | Mn3—O4—Na1xvi | 94.72 (9) |
O1ix—Na2—Al4x | 82.39 (8) | P2xv—O4—Mn1xvi | 120.11 (15) |
O3iv—Na2—Al4x | 151.88 (7) | Mn3—O4—Mn1xvi | 94.72 (9) |
O3xi—Na2—Al4x | 85.31 (5) | Na1xvi—O4—Mn1xvi | 0.0 |
Na2xii—Na2—Al4x | 120.32 (6) | P2xv—O4—Na1xv | 137.34 (16) |
Na2xiii—Na2—Al4x | 69.99 (4) | Mn3—O4—Na1xv | 87.88 (9) |
Mn4x—Na2—Al4x | 0.00 (3) | Na1xvi—O4—Na1xv | 83.23 (8) |
O1xi—Mn3—O1iv | 145.67 (12) | Mn1xvi—O4—Na1xv | 83.23 (8) |
O1xi—Mn3—O3xi | 72.27 (9) | P2xx—O5—Al4xvii | 139.22 (18) |
O1iv—Mn3—O3xi | 88.00 (9) | P2xx—O5—Mn4xvii | 139.22 (18) |
O1xi—Mn3—O3iv | 88.00 (9) | Al4xvii—O5—Mn4xvii | 0.00 (3) |
O1iv—Mn3—O3iv | 72.27 (9) | P2xx—O5—Mn4 | 121.51 (16) |
O3xi—Mn3—O3iv | 109.79 (14) | Al4xvii—O5—Mn4 | 97.08 (11) |
O1xi—Mn3—O4 | 117.07 (9) | Mn4xvii—O5—Mn4 | 97.08 (11) |
O1iv—Mn3—O4 | 90.52 (9) | P2xv—O6—Mn4 | 135.07 (18) |
O3xi—Mn3—O4 | 161.10 (9) | P2xv—O6—Na2ix | 110.99 (15) |
O3iv—Mn3—O4 | 87.61 (9) | Mn4—O6—Na2ix | 95.44 (12) |
O1xi—Mn3—O4xiv | 90.52 (9) | P2xv—O6—Na2vi | 109.82 (17) |
O1iv—Mn3—O4xiv | 117.07 (9) | Mn4—O6—Na2vi | 109.46 (12) |
O3xi—Mn3—O4xiv | 87.61 (9) | Na2ix—O6—Na2vi | 81.68 (9) |
Symmetry codes: (i) −x+1/2, −y+1/2, −z; (ii) x+1/2, y−1/2, z; (iii) x+1/2, −y+1/2, z−1/2; (iv) −x+1/2, y−1/2, −z+1/2; (v) −x+1/2, −y−1/2, −z; (vi) x+1/2, y+1/2, z; (vii) −x+1, y, −z−1/2; (viii) −x+1, y, −z+1/2; (ix) −x+1/2, −y+1/2, −z+1; (x) x−1/2, −y+1/2, z−1/2; (xi) x−1/2, y−1/2, z; (xii) −x, −y, −z+1; (xiii) −x, −y, −z; (xiv) −x, y, −z+1/2; (xv) −x+1/2, y+1/2, −z+1/2; (xvi) x−1/2, y+1/2, z; (xvii) −x+1/2, −y+3/2, −z+1; (xviii) −x, y−1, −z+1/2; (xix) x, y−1, z; (xx) x, y+1, z. |
Experimental details
Crystal data | |
Chemical formula | Na1.50Mn2.48Al0.85(PO4)3 |
Mr | 468.76 |
Crystal system, space group | Monoclinic, C2/c |
Temperature (K) | 293 |
a, b, c (Å) | 11.9816 (10), 12.5387 (13), 6.4407 (10) |
β (°) | 114.621 (8) |
V (Å3) | 879.64 (18) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 4.31 |
Crystal size (mm) | 0.23 × 0.07 × 0.05 |
Data collection | |
Diffractometer | Bruker P4 |
Absorption correction | ψ scan XSCANS in SHELXTL-Plus (Sheldrick, 1991) |
Tmin, Tmax | 0.761, 0.806 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 1271, 1019, 894 |
Rint | 0.024 |
(sin θ/λ)max (Å−1) | 0.650 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.032, 0.075, 1.07 |
No. of reflections | 1019 |
No. of parameters | 100 |
No. of restraints | 2 |
Δρmax, Δρmin (e Å−3) | 0.52, −0.65 |
Computer programs: XSCANS in SHELXTL-Plus (Sheldrick, 1991), XSCANS, SHELXTL-Plus, SHELXS97 (Sheldrick, 1990), SHELXL97 (Sheldrick, 1997), ATOMS (Dowty, 1993).
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In the natural geological environment of granitic pegmatites, alluaudite-type phosphates generally show chemical compositions comprised between Na2MnFe2+Fe3+(PO4)3 and NaMnFe3+2(PO4)3. The incorporation of significant amounts of aluminium into the crystal structure of these minerals produces a splitting of the M2 site of alluaudite into the M2a and M2b positions, thus leading to the more ordered wyllieite-type phosphates (Moore & Molin-Case, 1974; Hatert, Lefèvre et al., 2005). Consequently, the C2/c space group of alluaudite transforms into P21/n in wyllieite, with no significant change in the unit-cell parameters.
During the past 20 years, numerous alluaudite-type phosphates have been synthesized, and the crystal chemistry of this structure type is now well known (Hatert, 2004; Hatert, Rebbouh et al., 2005). Nevertheless, the structural descriptions of natural or synthetic wyllieite-type phosphates are rather scarce (Moore & Molin-Case, 1974; Zhesheng et al., 1983; Brier, 2000; Hatert, Lefèvre et al., 2005). In order to understand better the crystal chemistry of wyllieite-type phosphates, we attempted to obtain a single-crystal of wyllieite by hydrothermal synthesis at 1073 K and 0.1 GPa, starting from the composition Na2Mn2Al(PO4)3 (Hatert, 2002). The synthesized crystals were investigated by single-crystal X-ray diffraction techniques, and a careful examination of systematic absences indicated the C2/c space group, characteristic of alluaudite-type phosphates. The crystal structure of this Al-rich alluaudite-type compound is reported here.
The structure is similar to that of natural alluaudite, described by Moore (1971), and consists of kinked chains of edge-sharing octahedra stacked parallel to {101}. These chains are formed by a succession of M2–M2 octahedral pairs, linked by highly distorted M1 octahedra (Fig. 1). Equivalent chains are connected in the b direction by the P1 and P2 phosphate tetrahedra to form sheets oriented perpendicular to [010] (Fig. 2). These interconnected chains produce channels parallel to c, which contain the large distorted cubic A1 site and the A2' site with a morphology of a gabled disphenoid (Fig. 2). The site-occupancy factors indicate the following cationic distribution: 0.891 (10) Na+ in A2', 0.619 (8) Na+ + 0.381 (7) Mn2+ in A1, 0.908 (4) Mn2+ in M1, and 0.573 (6) Mn2+ + 0.427 (6) A l3+ in M2. This cationic distribution is in very good agreement with the chemical composition.
Bond-valence sums were calculated for each ion using the parameters of Brown & Altermatt (1985). The P1 and P2 bond-valence sums are 4.99 and 4.98, respectively, and the O-atom bond-valence sums are within the normal acceptable range (1.89–2.10). For the M1 site, the low bond-valence sum obtained in the preliminary calculations indicates an occupancy by ca 0.150 Na+ + 0.850 Mn2+.