Table 1. Various precursors, their contents and corresponding symbols used in the text. Groups and subgroups are explained in the text. The content weights are normalized to unity, and each precursor group contains ∼1300 atoms in total.
| Group | Subgroup | Content | Symbol |
| A | A1 | 1/2B 1/2N | B–N |
| 1/3B 2/3N | B–2N | ||
| 2/3B 1/3N | 2B–N | ||
| 1/4B 3/4N | B–3N | ||
| A2 | BN | BN | |
| B | B1 | 1/3B 1/3N 1/3H | BNH/111 |
| 1/4B 1/2N 1/4H | BNH/121 | ||
| 1/2B 1/4N 1/4H | BNH/211 | ||
| B2 | 4/5BN 1/5H | BN–H | |
| HBNH | HBNH | ||
| B3N3H6 | Boraz. | ||