Graphite</th>             <td align="right">graphite</td>   <td align="right">2 (a et c)</td> <td align="right">1 ou 2</td> </tr>
  <tr> <th align="left">Boron nitride or B12</th>        <td align="right">BN, B12</td>   <td align="right">2 (a and c)</td> <td align="right">2</td> </tr>
  <tr> <th align="left">Phase de Laves C14</th>             <td align="right">C14</td>   <td align="right">2 (a et c)</td> <td align="right">2</td> </tr>
  <tr> <th align="left">Phase de Laves C36</th>             <td align="r