ringliteral">&#39;K&#39;</span>, <span class="stringliteral">&#39;RB&#39;</span>,  <span class="comment"># group 1 cations</span></div><div class="line"><a name="l00008"></a><span class="lineno">    8</span>&#160;                                              <span class="stringliteral">&#39;BE&#39;</span>, <span class="stringliteral">&#39;MG&#39;</span>, <span class="stringliteral">&#39;CA&#39;</span>, <span class="stringliteral">&#39;SR&#39;</span>,  <span class="comment"># earth metal cations</span></div>