Kaitianite, Ti³⁺₂Ti⁴⁺O₅, is a new titanium oxide mineral discovered in the Allende CV3 carbonaceous chondrite. The type grain coexists with tistarite (Ti₂O₃) and rutile. Corundum, xifengite, mullite, osbornite, and a new Ti,Al,Zr‐oxide mineral are also present, although not in contact. The chemical composition of type kaitianite is (wt%) Ti₂O₃ 56.55, TiO₂ 39.29, Al₂O₃ 1.18, MgO 1.39, FeO 0.59, V₂O₃ 0.08 (sum 99.07), yielding an empirical formula of (Ti³⁺_(1.75)Al_(0.05)Ti⁴⁺_(0.10)Mg_(0.08)Fe_(0.02))(Ti⁴⁺_(1.00))O₅, with Ti³⁺ and Ti⁴⁺ partitioned, assuming a stoichiometry of three cations and five oxygen anions pfu. The end‐member formula is Ti³⁺₂Ti⁴⁺O₅. Kaitianite is the natural form of γ‐Ti₃O₅ with space group C2/c and cell parameters a = 10.115 A, b = 5.074 A, c = 7.182 A, β = 112o, V = 341.77 A³, and Z = 4. Both the type kaitianite and associated rutile likely formed as oxidation products of tistarite at temperatures below 1200 K, but this oxidation event could have been in a very reducing environment, even more reducing than a gas of solar composition. Based on experimental data on the solubility of Ti³⁺ in equilibrium with corundum from the literature, the absence of tistarite in or on Ti³⁺‐rich corundum (0.27–1.45 mol% Ti₂O₃) suggests that these grains formed at higher temperatures than the kaitianite (>1579–1696 K, depending on the Ti concentration). The absence of rutile or kaitianite in or on corundum suggests that any exposure to the oxidizing environment producing kaitianite in tistarite was too short to cause the precipitation of Ti‐oxides in or on associated corundum.

中文翻译：

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Kaitianite，Ti 3+ 2 Ti 4+ O 5 ，来自阿连德的一种新型氧化钛矿物

Kaitianite，Ti³⁺₂Ti⁴⁺O₅，是在阿连德CV3碳质球粒陨石中发现的一种新的氧化钛矿物。型粒与钛铁矿（Ti₂O₃）和金红石共存。刚玉、锡峰石、莫来石、钙镁石和一种新的钛、铝、锆氧化物矿物也存在，尽管没有接触。开天石型的化学成分为（wt%）Ti₂O₃ 56.55、TiO₂ 39.29、Al₂O₃ 1.18、MgO 1.39、FeO 0.59、V₂O₃ 0.08（总和为99.07），经验公式为（Ti11⁺）(Ti1₃3)(Ti1⁺)_Ti⁴3.5_Al⁴3.5 ⁺_(0.10)Mg_(0.08)Fe_(0.02))(Ti⁴⁺_(1.00))O₅，Ti³⁺和Ti⁴⁺被分配，假设化学计量为三个阳离子和五个氧阴离子pfu。端元分子式为 Ti³⁺₂Ti⁴⁺O₅。开天石是 γ-Ti₃O₅ 的天然形式，空间群为 C2/c，晶胞参数 a = 10.115 A，b = 5.074 A，c = 7.182 A，β = 112o，V = 341.77 A³，Z = 4。开天石和伴生的金红石都可能在低于 1200 K 的温度下作为钛铁矿的氧化产物形成，但这种氧化事件可能发生在非常还原的环境中，甚至比太阳成分的气体还原程度更高。根据文献中关于 Ti³⁺ 与刚玉平衡溶解度的实验数据，在富含 Ti³⁺ 的刚玉（0.27–1.45 mol% Ti₂O₃）中或上面不存在钛铁矿，表明这些晶粒形成于比开天石更高的温度（ >1579–1696 K，取决于 Ti 浓度）。刚玉中或刚玉上不存在金红石或开天石表明，任何暴露于氧化环境中在梯级石中产生开天石的时间太短，无法导致钛氧化物在相关刚玉中或上沉淀。