Beschreibung:
<jats:p>The crystal structure of the ternary germanide Li<jats:sub>2</jats:sub>MnGe has been re‐evaluated from single‐crystal X‐ray diffraction data. This compound crystallizes in a non‐centrosymmetric superstructure of the ZrCuSiAs type (space group <jats:italic>P</jats:italic>4<jats:italic>bm</jats:italic>, Pearson code <jats:italic>tP</jats:italic>16), with the lattice parameters <jats:italic>a</jats:italic> = 6.088(4) Å, <jats:italic>c</jats:italic> = 6.323(4) Å. First‐principle calculations for the idealized structure predict antiferromagnetic exchange in the square Mn nets and semimetallic ground state. In addition, a new ternary phase with the composition Li<jats:sub>2–<jats:italic>x</jats:italic></jats:sub>Mn<jats:sub>4+<jats:italic>x</jats:italic></jats:sub>Ge<jats:sub>5</jats:sub> (<jats:italic>x</jats:italic> ≈ 1.2) was discovered. It adopts the V<jats:sub>6</jats:sub>Si<jats:sub>5</jats:sub> structure type (space group <jats:italic>Ibam</jats:italic>, Pearson code <jats:italic>oI</jats:italic>44), with the lattice parameters <jats:italic>a</jats:italic> = 7.570(2) Å, <jats:italic>b</jats:italic> = 16.323(3) Å, <jats:italic>c</jats:italic> = 5.057(1) Å. DSC/TG measurements show that this compound is thermally stable below 995 K.</jats:p>