| Summary: | Kenoargentotetrahedrite-(Fe) is observed as greenish-grey anhedral grains, 50–150 μm in size, in association with galena, sphalerite and chalcopyrite in the Bajiazi Pb-Zn deposit of magmatic-hydrothermal type, Liaoning, China. The empirical formula from electron microprobe analyses is Ag<sub>5.50</sub>Cu<sub>4.17</sub>Fe<sub>1.75</sub>Zn<sub>0.31</sub>Sb<sub>3.96</sub>As<sub>0.04</sub>S<sub>12.08</sub>, corresponding to the ideal formula Ag<sub>6</sub>Cu<sub>4</sub>Fe<sub>2</sub>Sb<sub>4</sub>S<sub>12</sub>. The crystal structure of kenoargentotetrahedrite-(Fe) has been determined and refined by single-crystal X-ray diffraction with R<sub>1</sub> = 0.0192 for 1866 (404 unique) reflections. It is cubic, space group <i>I</i><inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mover accent="true"><mn>4</mn><mo>¯</mo></mover></semantics></math></inline-formula>3<i>m</i> with unit cell parameters <i>a</i> = 10.4928(2) Å, <i>V</i> = 1155.26(7) Å<sup>3</sup> and <i>Z</i> = 2. The structure of kenoargentotetrahedrite-(Fe) is characterized by a poor occupancy of 0.05 of the octahedral S(2) site with the S(2)-<i>M</i>(2) bonding length of 1.9994(8) Å. The six Ag atoms at <i>M</i>(2) around S(2) form an octahedron cluster (Ag<sub>6</sub>)<sup>4+</sup> with the valence state of +4 and Ag-Ag distance of 2.8276(1) Å. The structure is identical to that by Rozhdestvenskaya et al., being composed of a collapsed sodalite-like framework of corner-connected <i>M</i>(1)S<sub>4</sub> tetrahedron forming cages containing <i>M</i>(2)<sub>6</sub>-octahedron cluster, encircled by four SbS<sub>3</sub> trigonal pyramids. It is related to the tetrahedrite group minerals with the existence of the (Ag<sub>6</sub>)<sup>4+</sup> cluster replacing the S(2)-centered Ag<sub>6</sub> octahedron according to the substitution mechanism 6<i><sup>M</sup></i><sup>(2)</sup>Ag<sup>+</sup> + <sup>S(2)</sup>S<sup>2−</sup>=<i><sup>M</sup></i><sup>(2)</sup>(Ag<sub>6</sub>)<sup>4+</sup> + <sup>S(2)</sup> S.
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