Summary: Unusual clinopyroxenes were synthesized in the study of the join CaFeAlSiO₆-CaTiAl₂O₆ in air at I atm. Clinopyroxene solid solution, hibonite solid solution, X-phase, perovskite, and corundum are present, and at subsolidus temperatures the clinopyroxene singlephase field extends up to about 19 wt% CaTiAl₂O₆. The CaTiAl₂O₆ component in the clinopyroxene however increases beyond the clinopyroxene single-phase field and attains 23 wt%. These clinopyroxene solid solutions are extremely poor in SiO₂ and extremely rich in Al₂O₃, Fe₂O₃, and TiO₂, and more than half of tetrahedral sites are occupied by Al_IV, contravening the aluminium avoidance principle.