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The crystal structure of MgCoGa2 (magnesium cobalt digallide) was solved by direct methods and refined in two space groups as P21/c (standard choice) and P21/n (non-standard choice). The refined lattice parameters for the standard choice are a = 5.1505 (2), b = 7.2571 (2), c = 8.0264 (3) Å and β = 125.571 (3)°, and for the non-standard choice are a = 5.1505 (2), b = 7.2571 (2), c = 6.5464 (2) Å and β = 94.217 (3)°. All parameters for MgCoGa2 refined to R1 = 0.027 and wR2 = 0.042 using 594 reflections. The crystal structure peculiarities of this compound are discussed. Particular attention has been given to relationships with other similar structures, such as YPd2Si and Fe3C. Crystallographic analysis, together with linear muffin-tin orbital electronic structure calculations, reveals the presence of three-dimensional polyatomic nets with partial covalent bonding between the Ga atoms.
Supporting information
CCDC reference: 2000059
Data collection: CrysAlis PRO (Rigaku OD, 2015); cell refinement: CrysAlis PRO (Rigaku OD, 2015); data reduction: CrysAlis PRO (Rigaku OD, 2015); program(s) used to solve structure: SHELXT (Sheldrick, 2015a); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015b); molecular graphics: DIAMOND (Brandenburg, 2006); software used to prepare material for publication: SHELXL2014 (Sheldrick, 2015b).
Magnesium cobalt digallide
top
Crystal data top
MgCoGa2 | F(000) = 404 |
Mr = 222.68 | Dx = 6.061 Mg m−3 Dm = 6.08 (2) Mg m−3 Dm measured by volumetric |
Monoclinic, P21/c | Mo Kα radiation, λ = 0.71073 Å |
a = 5.1505 (2) Å | Cell parameters from 594 reflections |
b = 7.2571 (2) Å | θ = 4.2–28.5° |
c = 8.0264 (3) Å | µ = 28.48 mm−1 |
β = 125.571 (3)° | T = 293 K |
V = 244.03 (2) Å3 | Prism, metallic dark grey |
Z = 4 | 0.06 × 0.04 × 0.03 mm |
Data collection top
Agilent SuperNova Dual Source diffractometer with an Atlas detector | 594 independent reflections |
Radiation source: fine-focus sealed tube | 524 reflections with I > 2σ(I) |
Mirror monochromator | Rint = 0.035 |
ω scans | θmax = 28.5°, θmin = 4.2° |
Absorption correction: empirical (using intensity measurements) ABSPACK in CrysAlis PRO (Rigaku OD, 2015) | h = −6→6 |
Tmin = 0.284, Tmax = 0.409 | k = −9→9 |
3025 measured reflections | l = −10→10 |
Refinement top
Refinement on F2 | 0 restraints |
Least-squares matrix: full | Primary atom site location: structure-invariant direct methods |
R[F2 > 2σ(F2)] = 0.021 | Secondary atom site location: difference Fourier map |
wR(F2) = 0.042 | w = 1/[σ2(Fo2) + (0.0169P)2] where P = (Fo2 + 2Fc2)/3 |
S = 1.08 | (Δ/σ)max = 0.001 |
594 reflections | Δρmax = 1.05 e Å−3 |
37 parameters | Δρmin = −0.89 e Å−3 |
Special details top
Geometry. All esds (except the esd in the dihedral angle between two l.s. planes)
are estimated using the full covariance matrix. The cell esds are taken
into account individually in the estimation of esds in distances, angles
and torsion angles; correlations between esds in cell parameters are only
used when they are defined by crystal symmetry. An approximate (isotropic)
treatment of cell esds is used for estimating esds involving l.s. planes. |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top | x | y | z | Uiso*/Ueq | |
Mg | 0.1827 (3) | 0.04414 (19) | 0.2985 (2) | 0.0049 (3) | |
Co | 0.28699 (13) | 0.39736 (8) | 0.19208 (8) | 0.00378 (14) | |
Ga1 | 0.21859 (10) | 0.72437 (6) | 0.08003 (7) | 0.00448 (13) | |
Ga2 | 0.38498 (11) | 0.14078 (6) | 0.03372 (7) | 0.00476 (13) | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
Mg | 0.0046 (7) | 0.0055 (7) | 0.0039 (7) | 0.0008 (6) | 0.0021 (6) | 0.0007 (6) |
Co | 0.0033 (3) | 0.0038 (3) | 0.0029 (3) | −0.0004 (2) | 0.0011 (2) | −0.0005 (2) |
Ga1 | 0.0035 (2) | 0.0042 (2) | 0.0036 (2) | −0.00024 (18) | 0.00081 (19) | −0.00008 (18) |
Ga2 | 0.0054 (2) | 0.0049 (3) | 0.0033 (2) | 0.00067 (18) | 0.0021 (2) | −0.00014 (18) |
Geometric parameters (Å, º) top
Mg—Coi | 2.6843 (14) | Co—Mgx | 2.9112 (14) |
Mg—Ga2ii | 2.7550 (14) | Ga1—Covi | 2.3905 (7) |
Mg—Co | 2.8500 (14) | Ga1—Coviii | 2.4469 (7) |
Mg—Coiii | 2.8915 (14) | Ga1—Ga2viii | 2.6046 (7) |
Mg—Ga2iv | 2.8963 (15) | Ga1—Ga2xi | 2.8511 (6) |
Mg—Ga1ii | 2.9072 (14) | Ga1—Ga2vi | 2.8554 (6) |
Mg—Coii | 2.9111 (14) | Ga1—Mgx | 2.9072 (14) |
Mg—Ga2 | 2.9445 (13) | Ga1—Mgviii | 2.9449 (14) |
Mg—Ga1iii | 2.9450 (14) | Ga1—Mgxii | 2.9784 (14) |
Mg—Ga1v | 2.9785 (14) | Ga1—Mgvi | 3.0030 (14) |
Mg—Ga1vi | 3.0031 (14) | Ga1—Mgix | 3.0459 (13) |
Mg—Mgvii | 3.043 (3) | Ga2—Cox | 2.4981 (7) |
Co—Ga1vi | 2.3905 (7) | Ga2—Coiii | 2.5481 (7) |
Co—Ga1iii | 2.4469 (7) | Ga2—Ga2xiii | 2.5726 (8) |
Co—Ga2 | 2.4665 (7) | Ga2—Ga1iii | 2.6046 (7) |
Co—Ga1 | 2.4892 (7) | Ga2—Mgx | 2.7550 (14) |
Co—Ga2ii | 2.4981 (7) | Ga2—Ga1xi | 2.8511 (6) |
Co—Ga2viii | 2.5481 (7) | Ga2—Ga1vi | 2.8554 (6) |
Co—Mgix | 2.6843 (14) | Ga2—Mgiv | 2.8963 (15) |
Co—Mgviii | 2.8915 (14) | | |
| | | |
Coi—Mg—Ga2ii | 107.33 (5) | Ga2ii—Co—Mgx | 177.83 (4) |
Coi—Mg—Co | 134.06 (5) | Ga2viii—Co—Mgx | 116.57 (3) |
Ga2ii—Mg—Co | 52.90 (3) | Mgix—Co—Mgx | 111.86 (3) |
Coi—Mg—Coiii | 134.92 (5) | Mg—Co—Mgx | 120.56 (4) |
Ga2ii—Mg—Coiii | 108.23 (5) | Mgviii—Co—Mgx | 63.25 (5) |
Co—Mg—Coiii | 89.96 (4) | Covi—Ga1—Coviii | 168.36 (3) |
Coi—Mg—Ga2iv | 53.02 (3) | Covi—Ga1—Co | 80.08 (2) |
Ga2ii—Mg—Ga2iv | 142.40 (5) | Coviii—Ga1—Co | 110.61 (2) |
Co—Mg—Ga2iv | 113.97 (5) | Covi—Ga1—Ga2viii | 133.20 (2) |
Coiii—Mg—Ga2iv | 106.60 (4) | Coviii—Ga1—Ga2viii | 58.355 (18) |
Coi—Mg—Ga1ii | 50.43 (3) | Co—Ga1—Ga2viii | 59.982 (19) |
Ga2ii—Mg—Ga1ii | 101.30 (4) | Covi—Ga1—Ga2xi | 115.89 (2) |
Co—Mg—Ga1ii | 153.89 (6) | Coviii—Ga1—Ga2xi | 55.636 (17) |
Coiii—Mg—Ga1ii | 95.78 (4) | Co—Ga1—Ga2xi | 117.76 (2) |
Ga2iv—Mg—Ga1ii | 88.78 (4) | Ga2viii—Ga1—Ga2xi | 104.45 (2) |
Coi—Mg—Coii | 68.14 (3) | Covi—Ga1—Ga2vi | 55.235 (18) |
Ga2ii—Mg—Coii | 51.52 (3) | Coviii—Ga1—Ga2vi | 121.95 (2) |
Co—Mg—Coii | 104.24 (4) | Co—Ga1—Ga2vi | 109.95 (2) |
Coiii—Mg—Coii | 116.75 (5) | Ga2viii—Ga1—Ga2vi | 114.47 (2) |
Ga2iv—Mg—Coii | 121.12 (4) | Ga2xi—Ga1—Ga2vi | 128.99 (2) |
Ga1ii—Mg—Coii | 50.66 (3) | Covi—Ga1—Mgx | 59.95 (3) |
Coi—Mg—Ga2 | 144.88 (6) | Coviii—Ga1—Mgx | 119.53 (3) |
Ga2ii—Mg—Ga2 | 98.36 (4) | Co—Ga1—Mgx | 64.75 (3) |
Co—Mg—Ga2 | 50.35 (3) | Ga2viii—Ga1—Mgx | 114.87 (3) |
Coiii—Mg—Ga2 | 51.77 (3) | Ga2xi—Ga1—Mgx | 73.43 (3) |
Ga2iv—Mg—Ga2 | 92.15 (4) | Ga2vi—Ga1—Mgx | 114.58 (3) |
Ga1ii—Mg—Ga2 | 146.25 (5) | Covi—Ga1—Mgviii | 120.85 (3) |
Coii—Mg—Ga2 | 146.00 (5) | Coviii—Ga1—Mgviii | 63.02 (3) |
Coi—Mg—Ga1iii | 162.59 (6) | Co—Ga1—Mgviii | 63.65 (3) |
Ga2ii—Mg—Ga1iii | 59.92 (3) | Ga2viii—Ga1—Mgviii | 63.74 (3) |
Co—Mg—Ga1iii | 49.92 (3) | Ga2xi—Ga1—Mgviii | 56.73 (3) |
Coiii—Mg—Ga1iii | 50.48 (3) | Ga2vi—Ga1—Mgviii | 173.54 (3) |
Ga2iv—Mg—Ga1iii | 144.34 (5) | Mgx—Ga1—Mgviii | 62.65 (5) |
Ga1ii—Mg—Ga1iii | 117.35 (5) | Covi—Ga1—Mgxii | 114.71 (3) |
Coii—Mg—Ga1iii | 94.54 (4) | Coviii—Ga1—Mgxii | 63.53 (3) |
Ga2—Mg—Ga1iii | 52.49 (3) | Co—Ga1—Mgxii | 125.05 (3) |
Coi—Mg—Ga1v | 94.19 (4) | Ga2viii—Ga1—Mgxii | 75.81 (3) |
Ga2ii—Mg—Ga1v | 157.20 (5) | Ga2xi—Ga1—Mgxii | 102.85 (3) |
Co—Mg—Ga1v | 115.93 (4) | Ga2vi—Ga1—Mgxii | 59.49 (3) |
Coiii—Mg—Ga1v | 49.24 (2) | Mgx—Ga1—Mgxii | 169.16 (5) |
Ga2iv—Mg—Ga1v | 58.14 (3) | Mgviii—Ga1—Mgxii | 124.25 (3) |
Ga1ii—Mg—Ga1v | 86.43 (4) | Covi—Ga1—Mgvi | 62.59 (3) |
Coii—Mg—Ga1v | 135.81 (5) | Coviii—Ga1—Mgvi | 105.89 (3) |
Ga2—Mg—Ga1v | 65.89 (3) | Co—Ga1—Mgvi | 140.20 (4) |
Ga1iii—Mg—Ga1v | 97.43 (4) | Ga2viii—Ga1—Mgvi | 159.41 (3) |
Coi—Mg—Ga1vi | 98.59 (4) | Ga2xi—Ga1—Mgvi | 71.56 (3) |
Ga2ii—Mg—Ga1vi | 89.56 (4) | Ga2vi—Ga1—Mgvi | 60.28 (3) |
Co—Mg—Ga1vi | 48.12 (3) | Mgx—Ga1—Mgvi | 83.88 (2) |
Coiii—Mg—Ga1vi | 108.44 (4) | Mgviii—Ga1—Mgvi | 123.73 (5) |
Ga2iv—Mg—Ga1vi | 66.16 (3) | Mgxii—Ga1—Mgvi | 85.28 (4) |
Ga1ii—Mg—Ga1vi | 148.93 (5) | Covi—Ga1—Mgix | 63.41 (3) |
Coii—Mg—Ga1vi | 126.89 (5) | Coviii—Ga1—Mgix | 125.86 (3) |
Ga2—Mg—Ga1vi | 57.37 (3) | Co—Ga1—Mgix | 56.96 (3) |
Ga1iii—Mg—Ga1vi | 93.35 (4) | Ga2viii—Ga1—Mgix | 74.16 (3) |
Ga1v—Mg—Ga1vi | 94.72 (4) | Ga2xi—Ga1—Mgix | 174.61 (3) |
Coi—Mg—Mgvii | 108.35 (6) | Ga2vi—Ga1—Mgix | 55.55 (3) |
Ga2ii—Mg—Mgvii | 72.66 (5) | Mgx—Ga1—Mgix | 102.29 (3) |
Co—Mg—Mgvii | 103.58 (6) | Mgviii—Ga1—Mgix | 118.56 (5) |
Coiii—Mg—Mgvii | 58.69 (4) | Mgxii—Ga1—Mgix | 81.95 (2) |
Ga2iv—Mg—Mgvii | 140.00 (7) | Mgvi—Ga1—Mgix | 111.61 (5) |
Ga1ii—Mg—Mgvii | 59.28 (4) | Co—Ga2—Cox | 132.69 (2) |
Coii—Mg—Mgvii | 58.06 (4) | Co—Ga2—Coiii | 108.051 (18) |
Ga2—Mg—Mgvii | 101.84 (6) | Cox—Ga2—Coiii | 118.71 (2) |
Ga1iii—Mg—Mgvii | 58.07 (4) | Co—Ga2—Ga2xiii | 164.88 (3) |
Ga1v—Mg—Mgvii | 93.76 (6) | Cox—Ga2—Ga2xiii | 60.31 (2) |
Ga1vi—Mg—Mgvii | 151.03 (7) | Coiii—Ga2—Ga2xiii | 58.40 (2) |
Ga1vi—Co—Ga1iii | 126.89 (2) | Co—Ga2—Ga1iii | 57.623 (18) |
Ga1vi—Co—Ga2 | 72.00 (2) | Cox—Ga2—Ga1iii | 148.24 (2) |
Ga1iii—Co—Ga2 | 64.02 (2) | Coiii—Ga2—Ga1iii | 57.762 (19) |
Ga1vi—Co—Ga1 | 99.91 (2) | Ga2xiii—Ga2—Ga1iii | 107.30 (3) |
Ga1iii—Co—Ga1 | 128.77 (3) | Co—Ga2—Mgx | 67.51 (3) |
Ga2—Co—Ga1 | 124.19 (3) | Cox—Ga2—Mgx | 65.50 (3) |
Ga1vi—Co—Ga2ii | 112.28 (2) | Coiii—Ga2—Mgx | 164.53 (4) |
Ga1iii—Co—Ga2ii | 70.41 (2) | Ga2xiii—Ga2—Mgx | 123.50 (4) |
Ga2—Co—Ga2ii | 120.72 (2) | Ga1iii—Ga2—Mgx | 110.16 (3) |
Ga1—Co—Ga2ii | 113.45 (3) | Co—Ga2—Ga1xi | 107.77 (2) |
Ga1vi—Co—Ga2viii | 150.21 (3) | Cox—Ga2—Ga1xi | 53.954 (17) |
Ga1iii—Co—Ga2viii | 80.28 (2) | Coiii—Ga2—Ga1xi | 106.02 (2) |
Ga2—Co—Ga2viii | 137.46 (2) | Ga2xiii—Ga2—Ga1xi | 72.66 (2) |
Ga1—Co—Ga2viii | 62.26 (2) | Ga1iii—Ga2—Ga1xi | 95.144 (19) |
Ga2ii—Co—Ga2viii | 61.29 (2) | Mgx—Ga2—Ga1xi | 63.35 (3) |
Ga1vi—Co—Mgix | 69.63 (3) | Co—Ga2—Ga1vi | 52.768 (17) |
Ga1iii—Co—Mgix | 138.21 (4) | Cox—Ga2—Ga1vi | 101.53 (2) |
Ga2—Co—Mgix | 140.54 (4) | Coiii—Ga2—Ga1vi | 124.42 (2) |
Ga1—Co—Mgix | 72.03 (3) | Ga2xiii—Ga2—Ga1vi | 138.93 (3) |
Ga2ii—Co—Mgix | 67.85 (3) | Ga1iii—Ga2—Ga1vi | 104.750 (19) |
Ga2viii—Co—Mgix | 81.73 (3) | Mgx—Ga2—Ga1vi | 65.73 (3) |
Ga1vi—Co—Mg | 69.29 (3) | Ga1xi—Ga2—Ga1vi | 128.99 (2) |
Ga1iii—Co—Mg | 67.06 (3) | Co—Ga2—Mgiv | 115.13 (3) |
Ga2—Co—Mg | 66.81 (3) | Cox—Ga2—Mgiv | 59.14 (3) |
Ga1—Co—Mg | 162.56 (4) | Coiii—Ga2—Mgiv | 106.32 (3) |
Ga2ii—Co—Mg | 61.60 (3) | Ga2xiii—Ga2—Mgiv | 77.30 (3) |
Ga2viii—Co—Mg | 120.70 (4) | Ga1iii—Ga2—Mgiv | 151.19 (3) |
Mgix—Co—Mg | 91.05 (3) | Mgx—Ga2—Mgiv | 88.67 (2) |
Ga1vi—Co—Mgviii | 132.10 (4) | Ga1xi—Ga2—Mgiv | 113.06 (3) |
Ga1iii—Co—Mgviii | 67.23 (3) | Ga1vi—Ga2—Mgiv | 62.37 (3) |
Ga2—Co—Mgviii | 79.53 (3) | Co—Ga2—Mg | 62.84 (3) |
Ga1—Co—Mgviii | 65.87 (3) | Cox—Ga2—Mg | 146.67 (4) |
Ga2ii—Co—Mgviii | 115.31 (4) | Coiii—Ga2—Mg | 63.04 (3) |
Ga2viii—Co—Mgviii | 65.19 (3) | Ga2xiii—Ga2—Mg | 111.24 (4) |
Mgix—Co—Mgviii | 134.92 (5) | Ga1iii—Ga2—Mg | 63.76 (3) |
Mg—Co—Mgviii | 131.56 (4) | Mgx—Ga2—Mg | 122.74 (4) |
Ga1vi—Co—Mgx | 69.33 (3) | Ga1xi—Ga2—Mg | 158.89 (3) |
Ga1iii—Co—Mgx | 109.93 (3) | Ga1vi—Ga2—Mg | 62.34 (3) |
Ga2—Co—Mgx | 60.97 (3) | Mgiv—Ga2—Mg | 87.85 (4) |
Ga1—Co—Mgx | 64.59 (3) | | |
Symmetry codes: (i) −x, y−1/2, −z+1/2; (ii) x, −y+1/2, z+1/2; (iii) −x+1, y−1/2, −z+1/2; (iv) −x, −y, −z; (v) x, y−1, z; (vi) −x, −y+1, −z; (vii) −x+1, −y, −z+1; (viii) −x+1, y+1/2, −z+1/2; (ix) −x, y+1/2, −z+1/2; (x) x, −y+1/2, z−1/2; (xi) −x+1, −y+1, −z; (xii) x, y+1, z; (xiii) −x+1, −y, −z. |
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