span  title="" class="an ">&ensp;</span>between <span  title="" class="an ">&ensp;</span>those <span  title="" class="an ">&ensp;</span>of <span  title="" class="an ">&ensp;</span><span  title="CAP" class="an CAP">HCN</span><span  title="" class="an ">&ensp;</span>and <span  title="" class="an ">&ensp;</span><span  title="CAP" class="an CAP">HCN</span><span  title="" class="an ">&ensp;</span>homomers <span  title="" class="an ">&ensp;</span>although <span  title="" class="an ">&ensp;</span>the <span  title=