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The determination of the crystal structure of the M phase, (MnxZn1–x)2V2O7 (0.75 < x < 0.913), in the pseudobinary Mn2V2O7–Zn2V2O7 system for x ≃ 0.8 shows that the previously published triclinic unit-cell parameters for this thortveitite-related phase do not describe a true lattice for this phase. Instead, single-crystal X-ray data and Rietveld refinement of synchrotron X-ray powder data show that the M phase has a different triclinic structure in the space group P\overline{1} with Z = 2. As prior work has suggested, the crystal structure can be described as a distorted version of the thortveitite crystal structure of β-Mn2V2O7. A twofold superstructure in diffraction patterns of crystals of the M phase used for single-crystal X-ray diffraction work arises from twinning by reticular pseudomerohedry. This superstructure can be described as a commensurate modulation of a pseudo-monoclinic basis structure closely related to the crystal structure of β-Mn2V2O7. In comparison with the distortions introduced when β-Mn2V2O7 transforms at low temperature to α-Mn2V2O7, the distortions which give rise to the M phase from the β-Mn2V2O7 prototype are noticeably less pronounced.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S2053229618010458/rh3003sup1.cif
Contains datablocks sc, global, powder

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S2053229618010458/rh3003powdersup2.hkl
Contains datablock powder

pdf

Portable Document Format (PDF) file https://doi.org/10.1107/S2053229618010458/rh3003sup3.pdf
Synchrotron X-ray diffraction pattern obtained from the M phase

CCDC references: 1857048; 1857047

Computing details top

Data collection: APEX3 (Bruker, 2016) for sc. Cell refinement: SAINT-Plus (Bruker, 2016) for sc. Data reduction: SAINT-Plus (Bruker, 2016) for sc. Program(s) used to solve structure: SHELXT (Sheldrick, 2015) for sc. Program(s) used to refine structure: TOPAS4.2 (Coelho, 2009) for powder; JANA2006 (Petříček et al., 2014) for sc. For both structures, molecular graphics: CrystalMaker (Palmer, 2014); software used to prepare material for publication: publCIF (Westrip, 2010).

Manganese zinc divanadate (powder) top
Crystal data top
Mn1.60O7V2Zn0.40γ = 84.6100 (1)°
Mr = 327.94V = 279.97 (1) Å3
Triclinic, P1Z = 2
Hall symbol: -P 1Dx = 3.89 Mg m3
a = 6.88143 (1) ÅSynchrotron radiation, λ = 0.826406 Å
b = 7.92420 (1) ÅT = 298 K
c = 5.45516 (1) Ådark_grey
α = 84.5309 (1)°cylinder, 40 × 0.5 mm
β = 71.3730 (1)°
Data collection top
Beamline_I11,_Diamond_Light_Source
diffractometer
Scan method: continuous
Specimen mounting: Borosilicate glass capillary2θmin = 5.5°, 2θmax = 151.746°, 2θstep = 0.001°
Refinement top
Rp = 0.086Excluded region(s): 14.9-15.2, 19.25-19.35, 28.55-28.86, 28.925-29.05 degrees
Rwp = 0.11160 parameters
Rexp = 0.068(Δ/σ)max = 0.001
RBragg = 0.086Background function: Chebychev polynomial, Coefficient 0 64.55935 1 -48.25469 2 31.42671 3 -21.91713 4 15.57408 5 -10.13776 6 5.686649 7 -2.320198 8 -1.271288 9 1.725147 10 -3.066357
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/UeqOcc. (<1)
Mn10.16013 (8)0.14568 (6)0.81455 (9)0.0096 (1)0.8
Zn10.16013 (8)0.14568 (6)0.81455 (9)0.0096 (1)0.2
Mn20.65244 (7)0.66416 (6)0.81888 (9)0.0096 (1)0.8
Zn20.65244 (7)0.66416 (6)0.81888 (9)0.0096 (1)0.2
V10.82609 (7)0.42791 (6)0.24385 (9)0.0038 (1)
V20.30553 (8)0.90932 (6)0.28968 (9)0.0038 (1)
O10.2064 (3)0.7606 (3)0.5441 (4)0.0136 (1)
O20.4557 (3)0.1588 (2)0.8797 (4)0.0136 (1)
O30.9188 (3)0.6415 (2)0.9496 (4)0.0136 (1)
O40.3671 (3)0.5691 (3)0.8824 (4)0.0136 (1)
O50.8597 (3)0.0718 (3)0.8855 (4)0.0136 (1)
O60.6965 (4)0.9072 (3)0.5769 (4)0.0136 (1)
O70.2056 (3)0.4281 (3)0.5483 (4)0.0136 (1)
Geometric parameters (Å, º) top
Mn1—O5i2.107 (2)Mn2—O4iii2.328 (2)
Mn1—O6ii2.111 (2)Zn2—O42.082 (2)
Mn1—O3iii2.143 (2)Zn2—O7ii2.097 (2)
Mn1—O22.187 (2)Zn2—O32.156 (2)
Mn1—O5iv2.242 (2)Zn2—O2iii2.165 (2)
Mn1—O72.538 (2)Zn2—O62.216 (2)
Zn1—O5i2.107 (2)Zn2—O4iii2.328 (2)
Zn1—O6ii2.111 (2)V1—O7ii1.636 (2)
Zn1—O3iii2.143 (2)V1—O4ii1.679 (3)
Zn1—O22.187 (2)V1—O1ii1.785 (2)
Zn1—O5iv2.242 (2)V1—O3v1.801 (2)
Zn1—O72.538 (2)V1—O3vi2.209 (2)
Mn2—O42.082 (2)V2—O2ii1.674 (2)
Mn2—O7ii2.097 (2)V2—O6vii1.684 (2)
Mn2—O32.156 (2)V2—O5ii1.692 (3)
Mn2—O2iii2.165 (2)V2—O11.737 (2)
Mn2—O62.216 (2)
O5i—Mn1—O6ii102.45 (9)O7ii—Mn2—O680.00 (7)
O5i—Mn1—O3iii97.53 (8)O7ii—Mn2—O4iii106.30 (7)
O5i—Mn1—O2157.57 (8)O3—Mn2—O2iii81.75 (8)
O5i—Mn1—O5iv77.60 (10)O3—Mn2—O6101.54 (8)
O5i—Mn1—O7109.79 (8)O3—Mn2—O4iii70.19 (8)
O6ii—Mn1—O3iii139.34 (7)O2iii—Mn2—O680.30 (7)
O6ii—Mn1—O292.18 (8)O2iii—Mn2—O4iii92.63 (7)
O6ii—Mn1—O5iv117.25 (8)O6—Mn2—O4iii169.97 (9)
O6ii—Mn1—O772.62 (7)O4—Zn2—O7ii96.73 (9)
O3iii—Mn1—O281.54 (8)O4—Zn2—O3143.61 (8)
O3iii—Mn1—O5iv101.38 (8)O4—Zn2—O2iii95.31 (8)
O3iii—Mn1—O767.36 (7)O4—Zn2—O6113.77 (9)
O2—Mn1—O5iv80.61 (8)O4—Zn2—O4iii73.75 (10)
O2—Mn1—O790.66 (7)O7ii—Zn2—O397.79 (8)
O5iv—Mn1—O7166.84 (8)O7ii—Zn2—O2iii159.79 (7)
O5i—Zn1—O6ii102.45 (9)O7ii—Zn2—O680.00 (7)
O5i—Zn1—O3iii97.53 (8)O7ii—Zn2—O4iii106.30 (7)
O5i—Zn1—O2157.57 (8)O3—Zn2—O2iii81.75 (8)
O5i—Zn1—O5iv77.60 (10)O3—Zn2—O6101.54 (8)
O5i—Zn1—O7109.79 (8)O3—Zn2—O4iii70.19 (8)
O6ii—Zn1—O3iii139.34 (7)O2iii—Zn2—O680.30 (7)
O6ii—Zn1—O292.18 (8)O2iii—Zn2—O4iii92.63 (7)
O6ii—Zn1—O5iv117.25 (8)O6—Zn2—O4iii169.97 (9)
O6ii—Zn1—O772.62 (7)O7ii—V1—O4ii113.90 (11)
O3iii—Zn1—O281.54 (8)O7ii—V1—O1ii100.52 (10)
O3iii—Zn1—O5iv101.38 (8)O7ii—V1—O3v119.95 (11)
O3iii—Zn1—O767.36 (7)O4ii—V1—O1ii103.33 (10)
O2—Zn1—O5iv80.61 (8)O4ii—V1—O3v118.72 (10)
O2—Zn1—O790.66 (7)O1ii—V1—O3v93.80 (8)
O5iv—Zn1—O7166.84 (8)O2ii—V2—O6vii111.52 (11)
O4—Mn2—O7ii96.73 (9)O2ii—V2—O5ii113.18 (10)
O4—Mn2—O3143.61 (8)O2ii—V2—O1109.11 (9)
O4—Mn2—O2iii95.31 (8)O6vii—V2—O5ii110.53 (11)
O4—Mn2—O6113.77 (9)O6vii—V2—O1106.70 (10)
O4—Mn2—O4iii73.75 (10)O5ii—V2—O1105.39 (10)
O7ii—Mn2—O397.79 (8)V2—O1—V1ii162.74 (11)
O7ii—Mn2—O2iii159.79 (7)
Symmetry codes: (i) x1, y, z; (ii) x+1, y+1, z+1; (iii) x+1, y+1, z+2; (iv) x+1, y, z+2; (v) x+2, y+1, z+1; (vi) x, y, z1; (vii) x+1, y+2, z+1.
Manganese zinc divanadate (sc) top
Crystal data top
Mn1.612O7V2Zn0.388Z = 2
Mr = 327.8F(000) = 308
Triclinic, P1Dx = 3.907 Mg m3
Hall symbol: -P 1Mo Kα radiation, λ = 0.71075 Å
a = 6.8575 (2) ÅCell parameters from 1679 reflections
b = 7.9147 (3) Åθ = 3.1–43.1°
c = 5.4505 (6) ŵ = 8.45 mm1
α = 84.6178 (17)°T = 100 K
β = 71.450 (2)°Irregular, black
γ = 84.719 (2)°0.06 × 0.05 × 0.04 mm
V = 278.61 (3) Å3
Data collection top
Bruker Kappa APEXII CCD
diffractometer
3222 reflections with I > 3σ(I)
Radiation source: X-ray tubeRint = 0
ω– and φ–scansθmax = 43.3°, θmin = 3.1°
Absorption correction: multi-scan
(TWINABS; Bruker, 2016)
h = 913
Tmin = 0.60, Tmax = 0.71k = 1515
4889 measured reflectionsl = 108
4889 independent reflections
Refinement top
Refinement on F20 restraints
R[F > 3σ(F)] = 0.04231 constraints
wR(F) = 0.102Weighting scheme based on measured s.u.'s w = 1/(σ2(I) + 0.0004I2)
S = 1.18(Δ/σ)max = 0.033
4889 reflectionsΔρmax = 1.51 e Å3
110 parametersΔρmin = 1.54 e Å3
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/UeqOcc. (<1)
Mn10.15957 (12)0.14823 (12)0.81536 (13)0.01408 (14)0.798 (6)
Zn10.15957 (12)0.14823 (12)0.81536 (13)0.01408 (14)0.202 (6)
Mn20.65228 (11)0.66509 (12)0.81776 (13)0.01226 (13)0.814 (6)
Zn20.65228 (11)0.66509 (12)0.81776 (13)0.01226 (13)0.186 (6)
V10.82775 (17)0.42761 (14)0.2411 (4)0.0085 (2)0.843 (8)
V20.30349 (16)0.90968 (14)0.2939 (4)0.0087 (2)0.843 (8)
O10.2108 (3)0.7627 (2)0.5378 (4)0.0460 (9)
O20.4504 (3)0.1638 (3)0.8831 (5)0.0211 (7)
O30.9200 (3)0.6445 (3)0.9442 (5)0.0194 (6)
O40.3676 (5)0.5738 (5)0.8803 (8)0.0201 (8)
O50.8601 (5)0.0706 (5)0.8909 (7)0.0159 (7)
O60.6985 (5)0.9047 (5)0.5740 (7)0.0146 (7)
O70.2033 (6)0.4225 (5)0.5525 (7)0.0231 (9)
V2'0.3230 (8)0.9268 (7)0.2381 (15)0.0087 (2)0.157 (8)
V1'0.8062 (8)0.4121 (7)0.2971 (14)0.0085 (2)0.157 (8)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Mn10.01089 (16)0.0189 (2)0.0134 (2)0.00258 (14)0.00335 (11)0.00575 (13)
Zn10.01089 (16)0.0189 (2)0.0134 (2)0.00258 (14)0.00335 (11)0.00575 (13)
Mn20.01074 (17)0.0135 (2)0.0134 (2)0.00149 (13)0.00385 (11)0.00406 (11)
Zn20.01074 (17)0.0135 (2)0.0134 (2)0.00149 (13)0.00385 (11)0.00406 (11)
V10.0062 (2)0.0103 (2)0.0080 (5)0.00016 (15)0.0004 (2)0.0025 (2)
V20.0093 (2)0.0075 (2)0.0100 (5)0.00110 (15)0.0043 (2)0.0010 (2)
O10.0686 (14)0.0310 (12)0.0429 (13)0.0105 (10)0.0285 (11)0.0218 (9)
O20.0153 (8)0.0207 (9)0.0328 (13)0.0077 (6)0.0143 (6)0.0145 (7)
O30.0158 (8)0.0173 (8)0.0278 (12)0.0080 (6)0.0114 (6)0.0087 (6)
O40.0159 (11)0.0195 (12)0.0279 (13)0.0015 (9)0.0110 (10)0.0010 (11)
O50.0135 (10)0.0153 (10)0.0210 (11)0.0010 (8)0.0085 (9)0.0002 (9)
O60.0189 (11)0.0145 (10)0.0122 (9)0.0016 (8)0.0060 (8)0.0048 (8)
O70.0254 (12)0.0275 (15)0.0198 (12)0.0051 (10)0.0097 (10)0.0159 (12)
V2'0.0093 (2)0.0075 (2)0.0100 (5)0.00110 (15)0.0043 (2)0.0010 (2)
V1'0.0062 (2)0.0103 (2)0.0080 (5)0.00016 (15)0.0004 (2)0.0025 (2)
Geometric parameters (Å, º) top
Mn1—O22.157 (3)V1—V1'0.313 (7)
Mn1—O3i2.119 (3)V2—O11.683 (2)
Mn1—O5ii2.100 (4)V2—O2iii1.734 (2)
Mn1—O6iii2.099 (3)V2—O5iii1.719 (5)
Mn2—O2i2.121 (3)V2—O6v1.693 (4)
Mn2—O32.145 (3)V2—V2'0.314 (7)
Mn2—O42.059 (4)O1—V2'1.983 (7)
Mn2—O62.198 (4)O1—V1'iii1.570 (6)
Mn2—O7iii2.098 (4)O2—V2'iii1.611 (5)
Zn2—O42.059 (4)O3—V1'iv1.960 (5)
V1—O1iii1.822 (2)O4—V1'iii1.749 (9)
V1—O3iv1.776 (2)O5—V2'iii1.621 (9)
V1—O4iii1.674 (5)O6—V2'v1.724 (8)
V1—O7iii1.664 (5)O7—V1'iii1.594 (8)
O2—Mn1—O3i80.79 (10)Mn2i—O2—V2'iii128.8 (3)
O2—Mn1—O5ii156.43 (13)V2iii—O2—V2'iii9.9 (3)
O2—Mn1—O6iii92.92 (13)Mn1i—O3—Mn298.25 (9)
O3i—Mn1—O5ii97.32 (12)Mn1i—O3—V1iv126.60 (15)
O3i—Mn1—O6iii140.58 (13)Mn1i—O3—V1'iv125.7 (2)
O5ii—Mn1—O6iii102.73 (16)Mn2—O3—V1iv125.62 (17)
O2i—Mn2—O381.01 (10)Mn2—O3—V1'iv120.7 (3)
O2i—Mn2—O495.27 (13)V1iv—O3—V1'iv7.8 (2)
O2i—Mn2—O681.62 (12)Mn2—O4—Zn20.0 (5)
O2i—Mn2—O7iii159.11 (14)Mn2—O4—V1iii144.3 (2)
O3—Mn2—O4144.71 (14)Mn2—O4—V1'iii134.3 (3)
O3—Mn2—O6100.88 (13)Zn2—O4—V1iii144.3 (2)
O3—Mn2—O7iii97.24 (14)Zn2—O4—V1'iii134.3 (3)
O4—Mn2—O6113.35 (16)V1iii—O4—V1'iii10.18 (19)
O4—Mn2—O7iii97.81 (17)Mn1vi—O5—V2iii131.7 (2)
O6—Mn2—O7iii78.26 (15)Mn1vi—O5—V2'iii141.9 (3)
O1iii—V1—O3iv93.79 (11)V2iii—O5—V2'iii10.2 (2)
O1iii—V1—O4iii101.47 (17)Mn1iii—O6—Mn2109.52 (17)
O1iii—V1—O7iii100.95 (18)Mn1iii—O6—V2v126.5 (2)
O1iii—V1—V1'33.3 (10)Mn1iii—O6—V2'v136.8 (3)
O3iv—V1—O4iii119.67 (19)Mn2—O6—V2v120.5 (2)
O3iv—V1—O7iii119.76 (18)Mn2—O6—V2'v110.3 (3)
O3iv—V1—V1'122.0 (10)V2v—O6—V2'v10.5 (2)
O4iii—V1—O7iii113.9 (2)Mn2iii—O7—V1iii148.9 (2)
O4iii—V1—V1'98.8 (12)Mn2iii—O7—V1'iii138.5 (3)
O7iii—V1—V1'71.8 (12)V1iii—O7—V1'iii10.7 (2)
O1—V2—O2iii107.63 (12)V2—V2'—O115.6 (10)
O1—V2—O5iii106.84 (16)V2—V2'—O2iii108.0 (11)
O1—V2—O6v107.87 (17)V2—V2'—O5iii103.0 (12)
O1—V2—V2'161.6 (12)V2—V2'—O6v79.0 (13)
O2iii—V2—O5iii111.34 (18)O1—V2'—O2iii99.7 (3)
O2iii—V2—O6v112.52 (16)O1—V2'—O5iii98.1 (3)
O2iii—V2—V2'62.1 (10)O1—V2'—O6v94.5 (4)
O5iii—V2—O6v110.4 (2)O2iii—V2'—O5iii123.8 (5)
O5iii—V2—V2'66.7 (13)O2iii—V2'—O6v117.3 (4)
O6v—V2—V2'90.5 (12)O5iii—V2'—O6v113.7 (3)
V1iii—O1—V2165.08 (13)V1—V1'—O1iii140.5 (12)
V1iii—O1—V2'163.00 (19)V1—V1'—O3iv50.2 (8)
V1iii—O1—V1'iii6.3 (2)V1—V1'—O4iii71.1 (13)
V2—O1—V2'2.9 (2)V1—V1'—O7iii97.5 (12)
V2—O1—V1'iii159.2 (2)O1iii—V1'—O3iv95.6 (3)
V2'—O1—V1'iii156.9 (3)O1iii—V1'—O4iii109.2 (4)
Mn1—O2—Mn2i97.82 (8)O1iii—V1'—O7iii116.5 (5)
Mn1—O2—V2iii130.06 (17)O3iv—V1'—O4iii107.0 (4)
Mn1—O2—V2'iii133.3 (3)O3iv—V1'—O7iii113.3 (3)
Mn2i—O2—V2iii131.17 (16)O4iii—V1'—O7iii113.5 (4)
Symmetry codes: (i) x+1, y+1, z+2; (ii) x1, y, z; (iii) x+1, y+1, z+1; (iv) x+2, y+1, z+1; (v) x+1, y+2, z+1; (vi) x+1, y, z.
Comparison of atomic positions in the M phase (derived from the powder synchrotron refinement), represented in a pseudo-monoclinic unit cell, M', defined by Zhuravlev et al. (1993), and their corresponding positions in β-Mn2V2O7 representing the more general β-(Mn,Zn)2V2O7 high-temperature solid solution. top
Atom (M')Atom (β)x(M')y(M')z(M')x(β)y(β)z(β)ΔxΔyΔzShift (Å)
(Mn/Zn)1Mn0.00440.8102-0.01450.00.81090.0-0.00440.00070.01450.084
(Mn/Zn)2Mn0.00110.81770.01170.00.81090.0-0.0011-0.0068-0.01170.082
V1V0.75510.00110.39820.73410.00.4032-0.0210-0.00110.00500.149
V2V0.7126-0.00230.39620.73410.00.40320.02150.00230.00700.142
O1O10.53860.00550.55420.50.00.5-0.0386-0.0055-0.05420.330
O2O20.8826-0.00290.70310.90930.00.71910.02670.00290.01600.180
O3O20.94470.00490.72270.90930.00.7191-0.0354-0.0049-0.00360.238
O4O30.72310.15930.20190.73220.16140.21230.00910.00210.01040.072
O5O30.72710.15850.21210.73220.16140.21230.00510.00290.00020.043
O6O30.73660.15980.21070.73220.16140.2123-0.00440.00160.00160.036
O7O30.70730.15900.22260.73220.16140.21230.02490.0024-0.01030.187
Note: the components Δx, Δy and Δz of the shifts and the magnitudes of the shifts are all defined with respect to the β-Mn2V2O7 set of basis vectors quoted by Liao et al. (1996).
Selected bond lengths and angles (Å, °) top
Powder dataSingle-crystal data
(Mn/Zn)1—O5i2.107 (2)2.100 (4)
(Mn/Zn)1—O6ii2.111 (2)2.099 (3)
(Mn/Zn)1—O3iii2.143 (2)2.119 (3)
(Mn/Zn)1—O22.187 (2)2.157 (3)
(Mn/Zn)1—O5iv2.242 (2)2.229 (4)
(Mn/Zn)1—O72.538 (2)2.474 (4)
(Mn/Zn)2—O42.082 (2)2.059 (4)
(Mn/Zn)2—O7ii2.097 (2)2.098 (4)
(Mn/Zn)2—O32.156 (2)2.145 (3)
(Mn/Zn)2—O2iii2.165 (2)2.121 (3)
(Mn/Zn)2—O62.216 (2)2.198 (4)
(Mn/Zn)2—O4iii2.328 (2)2.371 (4)
V1—O7ii1.636 (2)1.664 (5)
V1—O4ii1.679 (3)1.674 (5)
V1—O1ii1.785 (2)1.822 (2)
V1—O3v1.801 (2)1.776 (2)
V1—O3vi2.209 (2)2.234 (3)
V1'—O7ii-1.594 (8)
V1'—O4ii-1.749 (9)
V1'—O1ii-1.570 (6)
V1'—O3v-1.960 (5)
V2—O2ii1.674 (2)1.734 (2)
V2—O6vii1.684 (2)1.693 (4)
V2—O5ii1.692 (3)1.719 (5)
V2—O11.737 (2)1.683 (2)
V2'—O2ii-1.611 (5)
V2'—O6vii-1.724 (8)
V2'—O5ii-1.621 (9)
V2'—O1-1.983 (7)
V2—O1—V1ii162.74 (11)165.08 (13)
V2—O1—V1'ii-159.2 (2)
V2'—O1—V1'ii-156.9 (3)
V2'—O1—V1ii-163.00 (19)

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