an class="nb">str</span><span class="p">(</span><span class="n">Specie</span><span class="o">.</span><span class="n">from_string</span><span class="p">(</span><span class="n">item</span><span class="p">)</span><span class="o">.</span><span class="n">element</span><span class="p">)</span>
    <span class="n">latmat</span> <span class="o">=</span> <span class="n">struct</span><span class="o">.</span><span class="n">lattice</span><span class="o">.</span><span class="n">matrix</span>
    <span class="n">connect