Table 1. Selected bond lengths (Å), angles (°) and torsion angles (°) of the H2btc− anion in 1.
| C10—C11 | 1.392 (2) | C7—C12 | 1.391 (2) | C8—C9 | 1.389 (2) |
| C11—C12 | 1.393 (2) | C7—C8 | 1.394 (2) | C9—C10 | 1.394 (2) |
| C11—C21 | 1.499 (2) | C7—C22 | 1.492 (2) | C9—C20 | 1.519 (2) |
| O1—C21 | 1.214 (2) | O3—C20 | 1.247 (2) | O5—C22 | 1.218 (2) |
| O2—C21 | 1.303 (2) | O4—C20 | 1.258 (2) | O6—C22 | 1.318 (2) |
| C10—C11—C12 | 119.68 (15) | C7—C12—C11 | 119.86 (16) | O1—C21—O2 | 124.30 (16) |
| C9—C8—C7 | 120.68 (15) | C12—C7—C8 | 119.93 (15) | O3—C20—O4 | 126.76 (17) |
| C8—C9—C10 | 118.98 (16) | C11—C10—C9 | 120.84 (15) | O5—C22—O6 | 124.31 (15) |
| C10—C11—C21—O1 | −4.4 (2) | C10—C9—C20—O4 | −173.05 (15) | C10—C11—C12—-C7 | 2.3 (2) |
| C12—C11—C21—O1 | 174.23 (16) | C8—C9—C20—O4 | 5.4 (2) | C12—C7—C8—C9 | 0.0 (2) |
| C10—C11—C21—O2 | 176.85 (15) | C12—C7—C22—O5 | −177.56 (16) | C7—C8—C9—C10 | 1.5 (2) |
| C12—C11—C21—O2 | −4.5 (2) | C8—C7—C22—O5 | 1.9 (2) | C8—C9—C10—C11 | −1.2 (2) |
| C10—C9—C20—O3 | 6.0 (2) | C12—C7—C22—O6 | 1.2 (2) | C8—C7—C12—C11 | −1.9 (2) |
| C8—C9—C20—O3 | −175.60 (15) | C8—C7—C22—O6 | −179.37 (15) | C9—C10—C11—C12 | −0.7 (2) |