Acta Cryst. (2008). E64, i23 [ doi:10.1107/S1600536808005783 ]
The title compound, Rb2Ga2O(BO3)2, is part of the homologous series A2Ga2O(BO3)2 (A = Na, K, Rb and Cs). The structure contains pairs of gallium-centered tetrahedra connected through a shared oxygen vertex. Orthoborate triangles connect the basal vertices of the tetrahedra, forming a three-dimensional network with voids occupied by rubidium ions.
Powders of Rb2Ga2O(BO3)2 were prepared from stoichiometric mixtures of RbNO3, Ga(NO3)3, and H3BO3, which were decomposed in alumina crucibles at 300 °C and then heated to 500 °C at 50 °C increments, with a soak of several hours at each temperature and intermediate grinding between each soak period. Crystals were grown in a platinum dish from a 1:1 molar mixture of the prepared powder in the presence of Rb3BO3 flux. The mixture was heated to 700 °C and cooled at 10 °C/hour to room temperature, and a single-crystal was cut from the crystal mass for subsequent X-ray diffraction analysis.
The highest peak and the deepest hole are located 0.74 Å and 1.13 Å, respectively, from Rb2.
Data collection: SMART (Bruker, 2005); cell refinement: SAINT-Plus (Bruker, 2003); data reduction: SAINT-Plus (Bruker, 2003); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg & Putz, 2007); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).
![[Figure 1]](./mg2048fig1thm.gif)
| Fig. 1. View of the unit cell along the b axis. Displacement ellipsoids are drawn at the 50% probability level. |
| Rb2Ga2O(BO3)2 | F000 = 808 |
| Mr = 444.00 | Dx = 3.727 Mg m−3 |
| Monoclinic, P21/c | Mo Kα radiation λ = 0.71073 Å |
| Hall symbol: -P 2ybc | Cell parameters from 1660 reflections |
| a = 8.8115 (18) Å | θ = 3.7–25.7º |
| b = 7.7224 (16) Å | µ = 19.03 mm−1 |
| c = 11.997 (3) Å | T = 297 (2) K |
| β = 104.246 (4)º | Block, colorless |
| V = 791.3 (3) Å3 | 0.23 × 0.21 × 0.19 mm |
| Z = 4 |
| Bruker SMART APEX CCD diffractometer | 1568 independent reflections |
| Radiation source: fine-focus sealed tube | 1151 reflections with I > 2σ(I) |
| Monochromator: graphite | Rint = 0.093 |
| T = 297(2) K | θmax = 26.1º |
| ω scans | θmin = 2.4º |
| Absorption correction: numerical (SADABS; Sheldrick, 2003) | h = −10→10 |
| Tmin = 0.118, Tmax = 0.429 | k = −9→9 |
| 8611 measured reflections | l = −14→14 |
| Refinement on F2 | Primary atom site location: structure-invariant direct methods |
| Least-squares matrix: full | Secondary atom site location: difference Fourier map |
| R[F2 > 2σ(F2)] = 0.037 | w = 1/[σ2(Fo2) + (0.0376P)2] where P = (Fo2 + 2Fc2)/3 |
| wR(F2) = 0.091 | (Δ/σ)max < 0.001 |
| S = 1.05 | Δρmax = 1.28 e Å−3 |
| 1568 reflections | Δρmin = −0.90 e Å−3 |
| 118 parameters | Extinction correction: none |
| Rb2Ga2O(BO3)2 | V = 791.3 (3) Å3 |
| Mr = 444.00 | Z = 4 |
| Monoclinic, P21/c | Mo Kα |
| a = 8.8115 (18) Å | µ = 19.03 mm−1 |
| b = 7.7224 (16) Å | T = 297 (2) K |
| c = 11.997 (3) Å | 0.23 × 0.21 × 0.19 mm |
| β = 104.246 (4)º |
| Bruker SMART APEX CCD diffractometer | 1568 independent reflections |
| Absorption correction: numerical (SADABS; Sheldrick, 2003) | 1151 reflections with I > 2σ(I) |
| Tmin = 0.118, Tmax = 0.429 | Rint = 0.093 |
| 8611 measured reflections |
| R[F2 > 2σ(F2)] = 0.037 | 118 parameters |
| wR(F2) = 0.091 | Δρmax = 1.28 e Å−3 |
| S = 1.05 | Δρmin = −0.90 e Å−3 |
| 1568 reflections |
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 | ||
| Rb1 | 0.05407 (9) | 0.12523 (11) | 0.15061 (7) | 0.0276 (2) | |
| Rb2 | 0.53288 (9) | 0.12728 (10) | 0.62677 (7) | 0.0265 (2) | |
| Ga1 | 0.84630 (9) | 0.12201 (10) | 0.38547 (7) | 0.0183 (2) | |
| Ga2 | 0.31410 (9) | 0.06933 (11) | 0.86673 (8) | 0.0191 (2) | |
| B1 | 0.6554 (10) | 0.0915 (10) | 0.9123 (8) | 0.0166 (19) | |
| B2 | 0.1834 (10) | 0.1269 (11) | 0.4388 (8) | 0.0181 (18) | |
| O1 | 0.5159 (5) | 0.0083 (6) | 0.8667 (5) | 0.0221 (13) | |
| O2 | 0.7394 (6) | 0.0677 (7) | 0.0235 (4) | 0.0249 (13) | |
| O3 | 0.7155 (6) | 0.1924 (7) | 0.8410 (5) | 0.0261 (13) | |
| O4 | 0.0442 (5) | 0.2139 (6) | 0.4178 (5) | 0.0247 (13) | |
| O5 | 0.3091 (5) | 0.2014 (6) | 0.4049 (5) | 0.0215 (12) | |
| O6 | 0.7902 (6) | 0.0280 (7) | 0.5097 (5) | 0.0286 (14) | |
| O7 | 0.1781 (6) | 0.0322 (7) | 0.7290 (5) | 0.0248 (12) |
| U11 | U22 | U33 | U12 | U13 | U23 | |
| Rb1 | 0.0180 (4) | 0.0338 (5) | 0.0310 (5) | −0.0050 (3) | 0.0063 (4) | −0.0004 (4) |
| Rb2 | 0.0225 (4) | 0.0282 (4) | 0.0260 (5) | 0.0032 (3) | 0.0008 (3) | −0.0024 (4) |
| Ga1 | 0.0125 (4) | 0.0193 (4) | 0.0237 (5) | 0.0007 (3) | 0.0055 (4) | 0.0004 (4) |
| Ga2 | 0.0122 (4) | 0.0203 (4) | 0.0252 (5) | −0.0007 (3) | 0.0052 (4) | 0.0005 (4) |
| B1 | 0.017 (4) | 0.011 (4) | 0.026 (5) | 0.003 (3) | 0.014 (4) | 0.000 (4) |
| B2 | 0.015 (4) | 0.017 (4) | 0.022 (5) | 0.000 (3) | 0.005 (4) | 0.002 (4) |
| O1 | 0.008 (3) | 0.022 (3) | 0.037 (4) | −0.001 (2) | 0.007 (2) | −0.005 (2) |
| O2 | 0.016 (3) | 0.031 (3) | 0.025 (3) | −0.008 (2) | 0.002 (2) | 0.010 (3) |
| O3 | 0.024 (3) | 0.024 (3) | 0.029 (3) | −0.012 (2) | 0.004 (3) | 0.000 (3) |
| O4 | 0.008 (3) | 0.023 (3) | 0.043 (4) | −0.006 (2) | 0.008 (2) | 0.001 (3) |
| O5 | 0.011 (3) | 0.021 (3) | 0.035 (3) | 0.001 (2) | 0.011 (2) | 0.004 (2) |
| O6 | 0.029 (3) | 0.024 (3) | 0.040 (4) | 0.004 (2) | 0.023 (3) | 0.010 (3) |
| O7 | 0.019 (3) | 0.026 (3) | 0.026 (3) | 0.003 (2) | −0.001 (2) | −0.006 (3) |
| Rb1—O2i | 2.851 (5) | Ga2—O2iv | 1.838 (5) |
| Rb1—O7ii | 2.928 (5) | Ga2—O5viii | 1.832 (5) |
| Rb1—O7iii | 3.034 (5) | Ga2—O7 | 1.810 (5) |
| Rb1—O4ii | 3.039 (5) | Ga2—Rb1iii | 3.5346 (12) |
| Rb1—O3iv | 3.170 (5) | Ga2—Rb2xiii | 3.6641 (13) |
| Rb1—B1iv | 3.298 (8) | Ga2—Rb1viii | 3.8226 (12) |
| Rb1—O4 | 3.300 (6) | Ga2—Rb2viii | 3.9973 (13) |
| Rb1—O4v | 3.341 (5) | B1—O1 | 1.376 (10) |
| Rb1—B2 | 3.363 (9) | B1—O2xiv | 1.370 (10) |
| Rb1—O5 | 3.365 (5) | B1—O3 | 1.358 (10) |
| Rb1—O2vi | 3.430 (6) | B1—Rb1iv | 3.298 (8) |
| Rb1—Ga2iii | 3.5346 (12) | B1—Rb2viii | 3.724 (8) |
| Rb2—O3 | 2.722 (5) | B2—O4 | 1.366 (9) |
| Rb2—O5 | 2.953 (5) | B2—O5 | 1.395 (9) |
| Rb2—O5iv | 2.964 (5) | B2—O6iv | 1.341 (10) |
| Rb2—O1vii | 2.977 (5) | B2—Rb2iv | 3.419 (8) |
| Rb2—O6 | 3.045 (5) | B2—Rb1viii | 3.584 (9) |
| Rb2—O1 | 3.060 (5) | O1—Rb2xiii | 2.977 (5) |
| Rb2—O6iv | 3.151 (6) | O2—B1xv | 1.370 (10) |
| Rb2—B2 | 3.340 (9) | O2—Ga2iv | 1.838 (5) |
| Rb2—B1 | 3.340 (9) | O2—Rb1ix | 2.851 (5) |
| Rb2—O2viii | 3.392 (6) | O2—Rb2ii | 3.392 (6) |
| Rb2—B2iv | 3.419 (8) | O2—Rb1vi | 3.430 (6) |
| Rb2—Rb2iv | 3.5477 (17) | O3—Ga1viii | 1.834 (5) |
| Ga1—O3ii | 1.834 (5) | O3—Rb1iv | 3.170 (5) |
| Ga1—O4ix | 1.834 (5) | O4—Ga1i | 1.834 (5) |
| Ga1—O6 | 1.831 (5) | O4—Rb1viii | 3.039 (5) |
| Ga1—O7iv | 1.790 (5) | O4—Rb1xvi | 3.341 (5) |
| Ga1—Rb1ix | 3.7189 (13) | O5—Ga2ii | 1.832 (5) |
| Ga1—Rb1x | 3.7966 (13) | O5—Rb2iv | 2.964 (5) |
| Ga1—Rb2iv | 3.8275 (13) | O6—B2iv | 1.341 (10) |
| Ga1—Rb1xi | 3.9828 (14) | O6—Rb2iv | 3.151 (6) |
| Ga1—Rb1xii | 4.0307 (14) | O7—Ga1iv | 1.790 (5) |
| Ga1—Rb2ii | 4.0975 (12) | O7—Rb1viii | 2.928 (5) |
| Ga2—O1 | 1.840 (5) | O7—Rb1iii | 3.034 (5) |
| O2i—Rb1—O7ii | 123.34 (15) | Rb1x—Ga1—Rb2iv | 121.81 (3) |
| O2i—Rb1—O7iii | 60.74 (14) | O7iv—Ga1—Rb1xi | 42.60 (17) |
| O7ii—Rb1—O7iii | 116.83 (11) | O6—Ga1—Rb1xi | 79.48 (16) |
| O2i—Rb1—O4ii | 76.60 (14) | O4ix—Ga1—Rb1xi | 99.91 (16) |
| O7ii—Rb1—O4ii | 81.35 (14) | O3ii—Ga1—Rb1xi | 149.37 (17) |
| O7iii—Rb1—O4ii | 137.01 (13) | Rb1ix—Ga1—Rb1xi | 76.19 (2) |
| O2i—Rb1—O3iv | 115.30 (15) | Rb1x—Ga1—Rb1xi | 120.83 (2) |
| O7ii—Rb1—O3iv | 120.23 (13) | Rb2iv—Ga1—Rb1xi | 74.04 (2) |
| O7iii—Rb1—O3iv | 100.16 (13) | O7iv—Ga1—Rb1xii | 123.18 (18) |
| O4ii—Rb1—O3iv | 102.65 (13) | O6—Ga1—Rb1xii | 125.38 (17) |
| O2i—Rb1—B1iv | 120.40 (19) | O4ix—Ga1—Rb1xii | 55.16 (16) |
| O7ii—Rb1—B1iv | 106.42 (17) | O3ii—Ga1—Rb1xii | 49.70 (17) |
| O7iii—Rb1—B1iv | 123.92 (17) | Rb1ix—Ga1—Rb1xii | 75.60 (2) |
| O4ii—Rb1—B1iv | 81.11 (18) | Rb1x—Ga1—Rb1xii | 61.41 (3) |
| O3iv—Rb1—B1iv | 24.13 (17) | Rb2iv—Ga1—Rb1xii | 133.78 (3) |
| O2i—Rb1—O4 | 107.29 (14) | Rb1xi—Ga1—Rb1xii | 149.02 (3) |
| O7ii—Rb1—O4 | 66.27 (13) | O7iv—Ga1—Rb2ii | 78.58 (17) |
| O7iii—Rb1—O4 | 55.84 (13) | O6—Ga1—Rb2ii | 122.49 (17) |
| O4ii—Rb1—O4 | 143.75 (4) | O4ix—Ga1—Rb2ii | 113.96 (17) |
| O3iv—Rb1—O4 | 107.42 (13) | O3ii—Ga1—Rb2ii | 32.03 (17) |
| B1iv—Rb1—O4 | 122.35 (19) | Rb1ix—Ga1—Rb2ii | 77.80 (3) |
| O2i—Rb1—O4v | 63.98 (14) | Rb1x—Ga1—Rb2ii | 119.20 (3) |
| O7ii—Rb1—O4v | 172.59 (13) | Rb2iv—Ga1—Rb2ii | 77.84 (2) |
| O7iii—Rb1—O4v | 64.64 (13) | Rb1xi—Ga1—Rb2ii | 119.89 (3) |
| O4ii—Rb1—O4v | 102.47 (12) | Rb1xii—Ga1—Rb2ii | 65.61 (2) |
| O3iv—Rb1—O4v | 52.94 (12) | O7—Ga2—O5viii | 109.3 (2) |
| B1iv—Rb1—O4v | 68.29 (16) | O7—Ga2—O2iv | 109.5 (2) |
| O4—Rb1—O4v | 111.63 (12) | O5viii—Ga2—O2iv | 110.6 (2) |
| O2i—Rb1—B2 | 126.09 (18) | O7—Ga2—O1 | 112.5 (2) |
| O7ii—Rb1—B2 | 70.20 (18) | O5viii—Ga2—O1 | 109.3 (2) |
| O7iii—Rb1—B2 | 67.02 (17) | O2iv—Ga2—O1 | 105.7 (2) |
| O4ii—Rb1—B2 | 150.35 (17) | O7—Ga2—Rb1iii | 59.13 (17) |
| O3iv—Rb1—B2 | 85.29 (17) | O5viii—Ga2—Rb1iii | 110.32 (14) |
| B1iv—Rb1—B2 | 98.7 (2) | O2iv—Ga2—Rb1iii | 53.43 (16) |
| O4—Rb1—B2 | 23.63 (16) | O1—Ga2—Rb1iii | 139.84 (15) |
| O4v—Rb1—B2 | 104.94 (17) | O7—Ga2—Rb2xiii | 91.67 (16) |
| O2i—Rb1—O5 | 148.92 (14) | O5viii—Ga2—Rb2xiii | 157.90 (16) |
| O7ii—Rb1—O5 | 55.79 (13) | O2iv—Ga2—Rb2xiii | 66.83 (17) |
| O7iii—Rb1—O5 | 90.94 (13) | O1—Ga2—Rb2xiii | 53.89 (15) |
| O4ii—Rb1—O5 | 128.56 (13) | Rb1iii—Ga2—Rb2xiii | 86.15 (3) |
| O3iv—Rb1—O5 | 80.03 (13) | O7—Ga2—Rb1viii | 47.68 (16) |
| B1iv—Rb1—O5 | 85.03 (18) | O5viii—Ga2—Rb1viii | 61.69 (16) |
| O4—Rb1—O5 | 41.80 (11) | O2iv—Ga2—Rb1viii | 128.63 (16) |
| O4v—Rb1—O5 | 117.62 (12) | O1—Ga2—Rb1viii | 125.18 (17) |
| B2—Rb1—O5 | 23.93 (16) | Rb1iii—Ga2—Rb1viii | 80.45 (2) |
| O2i—Rb1—O2vi | 101.45 (12) | Rb2xiii—Ga2—Rb1viii | 138.19 (3) |
| O7ii—Rb1—O2vi | 112.08 (14) | O7—Ga2—Rb2 | 71.19 (17) |
| O7iii—Rb1—O2vi | 129.57 (13) | O5viii—Ga2—Rb2 | 96.97 (15) |
| O4ii—Rb1—O2vi | 61.13 (12) | O2iv—Ga2—Rb2 | 149.64 (18) |
| O3iv—Rb1—O2vi | 41.56 (13) | O1—Ga2—Rb2 | 50.97 (17) |
| B1iv—Rb1—O2vi | 23.39 (18) | Rb1iii—Ga2—Rb2 | 128.63 (3) |
| O4—Rb1—O2vi | 145.74 (12) | Rb2xiii—Ga2—Rb2 | 82.84 (2) |
| O4v—Rb1—O2vi | 65.28 (12) | Rb1viii—Ga2—Rb2 | 75.46 (3) |
| B2—Rb1—O2vi | 122.11 (17) | O7—Ga2—Rb2viii | 152.81 (16) |
| O5—Rb1—O2vi | 106.98 (12) | O5viii—Ga2—Rb2viii | 43.56 (16) |
| O2i—Rb1—Ga2iii | 31.19 (10) | O2iv—Ga2—Rb2viii | 86.43 (17) |
| O7ii—Rb1—Ga2iii | 131.89 (11) | O1—Ga2—Rb2viii | 82.52 (16) |
| O7iii—Rb1—Ga2iii | 30.80 (10) | Rb1iii—Ga2—Rb2viii | 123.67 (3) |
| O4ii—Rb1—Ga2iii | 107.55 (9) | Rb2xiii—Ga2—Rb2viii | 115.16 (3) |
| O3iv—Rb1—Ga2iii | 104.14 (9) | Rb1viii—Ga2—Rb2viii | 105.14 (3) |
| B1iv—Rb1—Ga2iii | 121.58 (14) | Rb2—Ga2—Rb2viii | 106.28 (3) |
| O4—Rb1—Ga2iii | 84.39 (8) | O3—B1—O2xiv | 119.4 (7) |
| O4v—Rb1—Ga2iii | 53.33 (8) | O3—B1—O1 | 117.8 (8) |
| B2—Rb1—Ga2iii | 97.81 (14) | O2xiv—B1—O1 | 122.7 (7) |
| O5—Rb1—Ga2iii | 121.74 (8) | O3—B1—Rb1iv | 72.7 (4) |
| O2vi—Rb1—Ga2iii | 113.35 (9) | O2xiv—B1—Rb1iv | 83.7 (4) |
| O3—Rb2—O5 | 157.47 (16) | O1—B1—Rb1iv | 109.9 (4) |
| O3—Rb2—O5iv | 95.27 (15) | O3—B1—Rb2 | 52.0 (4) |
| O5—Rb2—O5iv | 106.33 (12) | O2xiv—B1—Rb2 | 166.2 (5) |
| O3—Rb2—O1vii | 81.27 (15) | O1—B1—Rb2 | 66.4 (4) |
| O5—Rb2—O1vii | 76.31 (14) | Rb1iv—B1—Rb2 | 83.14 (19) |
| O5iv—Rb2—O1vii | 157.67 (13) | O3—B1—Rb2viii | 109.0 (5) |
| O3—Rb2—O6 | 98.49 (16) | O2xiv—B1—Rb2viii | 65.4 (4) |
| O5—Rb2—O6 | 92.34 (14) | O1—B1—Rb2viii | 99.5 (4) |
| O5iv—Rb2—O6 | 45.46 (13) | Rb1iv—B1—Rb2viii | 145.8 (3) |
| O1vii—Rb2—O6 | 112.93 (14) | Rb2—B1—Rb2viii | 125.8 (2) |
| O3—Rb2—O1 | 47.31 (13) | O6iv—B2—O4 | 124.7 (7) |
| O5—Rb2—O1 | 136.88 (12) | O6iv—B2—O5 | 116.3 (7) |
| O5iv—Rb2—O1 | 89.80 (13) | O4—B2—O5 | 119.0 (7) |
| O1vii—Rb2—O1 | 103.37 (11) | O6iv—B2—Rb2 | 70.3 (4) |
| O6—Rb2—O1 | 124.94 (13) | O4—B2—Rb2 | 139.5 (5) |
| O3—Rb2—O6iv | 144.03 (14) | O5—B2—Rb2 | 62.0 (4) |
| O5—Rb2—O6iv | 44.59 (13) | O6iv—B2—Rb1 | 116.6 (5) |
| O5iv—Rb2—O6iv | 90.03 (13) | O4—B2—Rb1 | 75.6 (4) |
| O1vii—Rb2—O6iv | 105.77 (13) | O5—B2—Rb1 | 78.1 (4) |
| O6—Rb2—O6iv | 110.17 (11) | Rb2—B2—Rb1 | 135.8 (3) |
| O1—Rb2—O6iv | 97.31 (13) | O6iv—B2—Rb2iv | 62.6 (4) |
| O3—Rb2—B2 | 150.50 (19) | O4—B2—Rb2iv | 156.1 (6) |
| O5—Rb2—B2 | 24.64 (17) | O5—B2—Rb2iv | 59.4 (4) |
| O5iv—Rb2—B2 | 107.28 (18) | Rb2—B2—Rb2iv | 63.31 (15) |
| O1vii—Rb2—B2 | 84.46 (17) | Rb1—B2—Rb2iv | 80.99 (19) |
| O6—Rb2—B2 | 110.85 (19) | O6iv—B2—Rb1viii | 101.5 (5) |
| O1—Rb2—B2 | 112.62 (17) | O4—B2—Rb1viii | 56.0 (4) |
| O6iv—Rb2—B2 | 23.61 (16) | O5—B2—Rb1viii | 113.6 (5) |
| O3—Rb2—B1 | 23.13 (17) | Rb2—B2—Rb1viii | 85.5 (2) |
| O5—Rb2—B1 | 156.39 (16) | Rb1—B2—Rb1viii | 130.1 (2) |
| O5iv—Rb2—B1 | 90.97 (16) | Rb2iv—B2—Rb1viii | 148.0 (3) |
| O1vii—Rb2—B1 | 93.85 (17) | B1—O1—Ga2 | 130.5 (5) |
| O6—Rb2—B1 | 111.28 (17) | B1—O1—Rb2xiii | 124.9 (4) |
| O1—Rb2—B1 | 24.32 (16) | Ga2—O1—Rb2xiii | 96.17 (18) |
| O6iv—Rb2—B1 | 121.60 (17) | B1—O1—Rb2 | 89.3 (4) |
| B2—Rb2—B1 | 134.8 (2) | Ga2—O1—Rb2 | 101.2 (2) |
| O3—Rb2—O2viii | 88.32 (14) | Rb2xiii—O1—Rb2 | 111.24 (16) |
| O5—Rb2—O2viii | 80.53 (13) | B1xv—O2—Ga2iv | 127.1 (5) |
| O5iv—Rb2—O2viii | 103.70 (12) | B1xv—O2—Rb1ix | 136.1 (4) |
| O1vii—Rb2—O2viii | 54.35 (12) | Ga2iv—O2—Rb1ix | 95.4 (2) |
| O6—Rb2—O2viii | 58.60 (12) | B1xv—O2—Rb2ii | 93.0 (4) |
| O1—Rb2—O2viii | 134.98 (13) | Ga2iv—O2—Rb2ii | 83.28 (19) |
| O6iv—Rb2—O2viii | 124.89 (13) | Rb1ix—O2—Rb2ii | 103.59 (16) |
| B2—Rb2—O2viii | 104.03 (17) | B1xv—O2—Rb1vi | 72.9 (4) |
| B1—Rb2—O2viii | 111.40 (16) | Ga2iv—O2—Rb1vi | 117.0 (2) |
| O3—Rb2—B2iv | 91.56 (19) | Rb1ix—O2—Rb1vi | 78.55 (12) |
| O5—Rb2—B2iv | 105.54 (18) | Rb2ii—O2—Rb1vi | 159.51 (17) |
| O5iv—Rb2—B2iv | 23.90 (16) | B1—O3—Ga1viii | 125.4 (5) |
| O1vii—Rb2—B2iv | 133.78 (17) | B1—O3—Rb2 | 104.9 (5) |
| O6—Rb2—B2iv | 23.01 (17) | Ga1viii—O3—Rb2 | 127.0 (2) |
| O1—Rb2—B2iv | 104.57 (17) | B1—O3—Rb1iv | 83.2 (4) |
| O6iv—Rb2—B2iv | 106.29 (17) | Ga1viii—O3—Rb1iv | 104.1 (2) |
| B2—Rb2—B2iv | 116.69 (15) | Rb2—O3—Rb1iv | 96.45 (16) |
| B1—Rb2—B2iv | 96.8 (2) | B2—O4—Ga1i | 127.8 (5) |
| O2viii—Rb2—B2iv | 80.00 (16) | B2—O4—Rb1viii | 102.1 (5) |
| O3—Rb2—Rb2iv | 147.74 (12) | Ga1i—O4—Rb1viii | 99.4 (2) |
| O5—Rb2—Rb2iv | 53.31 (10) | B2—O4—Rb1 | 80.8 (4) |
| O5iv—Rb2—Rb2iv | 53.02 (10) | Ga1i—O4—Rb1 | 88.01 (19) |
| O1vii—Rb2—Rb2iv | 125.17 (11) | Rb1viii—O4—Rb1 | 167.46 (17) |
| O6—Rb2—Rb2iv | 56.49 (11) | B2—O4—Rb1xvi | 132.8 (4) |
| O1—Rb2—Rb2iv | 127.20 (10) | Ga1i—O4—Rb1xvi | 98.07 (19) |
| O6iv—Rb2—Rb2iv | 53.68 (10) | Rb1viii—O4—Rb1xvi | 77.53 (12) |
| B2—Rb2—Rb2iv | 59.44 (15) | Rb1—O4—Rb1xvi | 91.48 (13) |
| B1—Rb2—Rb2iv | 140.98 (13) | B2—O5—Ga2ii | 122.8 (5) |
| O2viii—Rb2—Rb2iv | 93.49 (9) | B2—O5—Rb2 | 93.4 (4) |
| B2iv—Rb2—Rb2iv | 57.25 (15) | Ga2ii—O5—Rb2 | 111.1 (2) |
| O7iv—Ga1—O6 | 110.8 (2) | B2—O5—Rb2iv | 96.7 (4) |
| O7iv—Ga1—O4ix | 110.4 (2) | Ga2ii—O5—Rb2iv | 139.0 (2) |
| O6—Ga1—O4ix | 114.5 (2) | Rb2—O5—Rb2iv | 73.67 (11) |
| O7iv—Ga1—O3ii | 110.4 (2) | B2—O5—Rb1 | 77.9 (4) |
| O6—Ga1—O3ii | 105.7 (2) | Ga2ii—O5—Rb1 | 89.68 (19) |
| O4ix—Ga1—O3ii | 104.8 (2) | Rb2—O5—Rb1 | 158.76 (17) |
| O7iv—Ga1—Rb1ix | 53.98 (17) | Rb2iv—O5—Rb1 | 87.95 (13) |
| O6—Ga1—Rb1ix | 154.26 (16) | B2iv—O6—Ga1 | 132.7 (5) |
| O4ix—Ga1—Rb1ix | 62.46 (17) | B2iv—O6—Rb2 | 94.4 (4) |
| O3ii—Ga1—Rb1ix | 99.52 (17) | Ga1—O6—Rb2 | 131.0 (2) |
| O7iv—Ga1—Rb1x | 157.95 (16) | B2iv—O6—Rb2iv | 86.1 (4) |
| O6—Ga1—Rb1x | 72.13 (18) | Ga1—O6—Rb2iv | 96.8 (2) |
| O4ix—Ga1—Rb1x | 52.16 (17) | Rb2—O6—Rb2iv | 69.83 (11) |
| O3ii—Ga1—Rb1x | 88.92 (17) | Ga1iv—O7—Ga2 | 137.2 (3) |
| Rb1ix—Ga1—Rb1x | 113.93 (3) | Ga1iv—O7—Rb1viii | 113.0 (2) |
| O7iv—Ga1—Rb2iv | 72.36 (17) | Ga2—O7—Rb1viii | 105.1 (2) |
| O6—Ga1—Rb2iv | 54.84 (18) | Ga1iv—O7—Rb1iii | 97.5 (2) |
| O4ix—Ga1—Rb2iv | 168.11 (17) | Ga2—O7—Rb1iii | 90.1 (2) |
| O3ii—Ga1—Rb2iv | 84.37 (17) | Rb1viii—O7—Rb1iii | 105.83 (16) |
| Rb1ix—Ga1—Rb2iv | 124.20 (3) |
| Symmetry codes: (i) x−1, y, z; (ii) x, −y+1/2, z−1/2; (iii) −x, −y, −z+1; (iv) −x+1, −y, −z+1; (v) −x, y−1/2, −z+1/2; (vi) −x+1, −y, −z; (vii) −x+1, y+1/2, −z+3/2; (viii) x, −y+1/2, z+1/2; (ix) x+1, y, z; (x) x+1, −y+1/2, z+1/2; (xi) −x+1, y−1/2, −z+1/2; (xii) −x+1, y+1/2, −z+1/2; (xiii) −x+1, y−1/2, −z+3/2; (xiv) x, y, z+1; (xv) x, y, z−1; (xvi) −x, y+1/2, −z+1/2. |
| Ga1—O3i | 1.834 (5) | Ga2—O7 | 1.810 (5) |
| Ga1—O4ii | 1.834 (5) | B1—O1 | 1.376 (10) |
| Ga1—O6 | 1.831 (5) | B1—O2v | 1.370 (10) |
| Ga1—O7iii | 1.790 (5) | B1—O3 | 1.358 (10) |
| Ga2—O1 | 1.840 (5) | B2—O4 | 1.366 (9) |
| Ga2—O2iii | 1.838 (5) | B2—O5 | 1.395 (9) |
| Ga2—O5iv | 1.832 (5) | B2—O6iii | 1.341 (10) |
| O7iii—Ga1—O6 | 110.8 (2) | O7—Ga2—O1 | 112.5 (2) |
| O7iii—Ga1—O4ii | 110.4 (2) | O5iv—Ga2—O1 | 109.3 (2) |
| O6—Ga1—O4ii | 114.5 (2) | O2iii—Ga2—O1 | 105.7 (2) |
| O7iii—Ga1—O3i | 110.4 (2) | O3—B1—O2v | 119.4 (7) |
| O6—Ga1—O3i | 105.7 (2) | O3—B1—O1 | 117.8 (8) |
| O4ii—Ga1—O3i | 104.8 (2) | O2v—B1—O1 | 122.7 (7) |
| O7—Ga2—O5iv | 109.3 (2) | O6iii—B2—O4 | 124.7 (7) |
| O7—Ga2—O2iii | 109.5 (2) | O6iii—B2—O5 | 116.3 (7) |
| O5iv—Ga2—O2iii | 110.6 (2) | O4—B2—O5 | 119.0 (7) |
| Symmetry codes: (i) x, −y+1/2, z−1/2; (ii) x+1, y, z; (iii) −x+1, −y, −z+1; (iv) x, −y+1/2, z+1/2; (v) x, y, z+1. |
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Bruker (2005). SMART. Bruker AXS Inc., Madison, Wisconson, USA.
Chen, C., Lin, Z. & Wang, Z. (2004). Appl. Phys. B80, 1–25.
Corbel, G. & Leblanc, M. (2000). J. Solid State Chem. 154, 344–349.
Sheldrick, G. M. (2003). SADABS.University of Göttingen, Germany.
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122.
Smith, R. W. (1995). Acta Cryst. C51, 547–549.
Smith, R. W., Kennard, M. A. & Dudik, M. J. (1997). Mater. Res. Bull. 32, 649–656.
Complex metal borates adopt various structure types that result from the many possible geometric arrangements formed by metal-centered polyhedra and borate anions, which can be either three- or four-coordinate. They are also of interest as nonlinear optical materials, such as β-BaB2O4, LiB3O5, and YAl3(BO3)4 (Chen et al., 2004). For these reasons, we have examined the phase diagrams of alkali metal gallium borates and have determined the crystal structures of some of the materials discovered. The homologous series A2Ga2O(BO3)2 (A = Na, K, Rb, Cs) is a portion of the new compounds discovered to date. In each, pairs of gallium-centered tetrahedra are connected through a shared oxygen vertex, and the tetrahedral basal planes are connected through shared oxygen vertices with triangular orthoborate anions. Depending on the size of the alkali metal ions, which occupy channels or spaces within the three-dimensional network, the compounds crystallize in different space groups: P31c for the Na member (Corbel & Leblanc, 2000), P321 for the K member (Smith et al., 1997), and P21/c for the Cs member (Smith, 1995), which is isotypic with the Rb compound reported herein (Fig. 1).