Hochleitnerite, [K(H ₂O)]Mn ₂(Ti ₂Fe)(PO ₄) ₄O ₂(H ₂O) ₁₀  ⋅  4H ₂O, a new paulkerrite-group mineral, from the Hagendorf-Süd pegmatite, Oberpfalz, Bavaria, Germany

Hochleitnerite, [K(Hinline-formula₂O)]Mninline-formula₂(Tiinline-formula₂Fe)(POinline-formula₄)inline-formula₄Oinline-formula₂(Hinline-formula₂O)inline-formula₁₀ inline-formula⋅ 4Hinline-formula₂O, is a new paulkerrite-group mineral from the Hagendorf-Süd pegmatite, Oberpfalz, Bavaria, Germany. It was found in specimens of altered zwieselite, in association with fluorapatite, rockbridgeite, columbite and sub-micrometre rods of uranophane. Hochleitnerite occurs as isolated and intergrown pale-yellow, diamond-shaped tablets with thicknesses reaching 50 inline-formulaµm and lengths of 120 inline-formulaµm. The crystals are flattened on {010}, slightly elongated on [001], and bounded by the {111} and {010} forms. The calculated density is 2.40 g cminline-formula⁻³. Optically, hochleitnerite crystals are biaxial (inline-formula+), with inline-formulaα= 1.615(2), inline-formulaβ= 1.621(2) and inline-formulaγ= 1.645(2) (measured in white light). The calculated 2inline-formulaV is 53.8inline-formula^∘. The empirical formula is [K(Hinline-formula₂O)](Mninline-formula $M31inlinescrollmathml{}_{\mathrm{normal\; 1.51}}^{\mathrm{normal\; 2}+}$ 18pt17ptsvg-formulamathimg053f807f6aa77b8dca748130b9474be3 ejm-35-635-2023-ie00001.svg18pt17ptejm-35-635-2023-ie00001.png Feinline-formula $M32inlinescrollmathml{}_{\mathrm{normal\; 0.49}}^{\mathrm{normal\; 2}+}$ 18pt17ptsvg-formulamathimg247605b2ce1309402125178ad6c3d894 ejm-35-635-2023-ie00002.svg18pt17ptejm-35-635-2023-ie00002.png )inline-formula_Σ2.00(Tiinline-formula $M34inlinescrollmathml{}_{\mathrm{normal\; 1.62}}^{\mathrm{normal\; 4}+}$ 18pt17ptsvg-formulamathimgc530ddfe2fc4911e79964c174309f135 ejm-35-635-2023-ie00003.svg18pt17ptejm-35-635-2023-ie00003.png Feinline-formula $M35inlinescrollmathml{}_{\mathrm{normal\; 0.19}}^{\mathrm{normal\; 3}+}$ 18pt17ptsvg-formulamathimg3d77ceb66795aaf04c45000a3c6e3b58 ejm-35-635-2023-ie00004.svg18pt17ptejm-35-635-2023-ie00004.png Alinline-formula_0.15)inline-formula_Σ2.96(POinline-formula₄)_4.00[Oinline-formula_1.50Finline-formula_0.23(OH)inline-formula_0.27]inline-formula_Σ2.00(Hinline-formula₂O)inline-formula₁₀ inline-formula⋅ 4Hinline-formula₂O. Hochleitnerite has space group Pbca and unit-cell parameters inline-formulaa= 10.5513(3) Å, inline-formulab= 20.6855(17) Å, inline-formulac= 12.4575(4) Å, inline-formulaV= 2718.96(15) Åinline-formula³ and inline-formulaZ= 4. The crystal structure was refined using single-crystal data to wRinline-formula_obs= 0.082 for 2242 reflections with inline-formulaI inline-formula> 3inline-formulaσ(I). The crystal structure contains corner-connected linear trimers of Ti-centred octahedra that share corners with POinline-formula₄ tetrahedra to form 10-member rings parallel to (010). Kinline-formula⁺ cations and water molecules are located within the rings. Additional corner sharing of the POinline-formula₄ tetrahedra with MnOinline-formula₂(Hinline-formula₂O)inline-formula₄ octahedra occurs along [010] to complete the 3D framework structure.