n>,  <span class="comment"># cu-o-cu linkage</span></div><div class="line"><a name="l00047"></a><span class="lineno">   47</span>&#160;                                              <span class="stringliteral">&#39;BNZ&#39;</span>,  <span class="comment"># benzene</span></div><div class="line"><a name="l00048"></a><span class="lineno">   48</span>&#160;                                              <span class="stringliteral">&#39;TCN&#39;</span>,  <span class="comment"># tetracyanonickelate ion</span></div><