Abstract: An organic aluminoxy compound which shows 27Al nuclear magnetic resonance spectrum (27Al-NMR spectrum) having an A1/A2 ratio of at most 0.1, wherein A1 is area of a region encompassed by a segment of a line which connects a local minimum point existing between a continuous curve “a” containing a peak appearing at around 150 ppm and a continuous curve “b” containing a peak appearing at around 60 ppm to the point where the above curve “b” comes into contact with the base line and also by the above curve “b” and A2 is area of a region encompassed by the above curves “a” and “b” and also by the base line; an organic aluminoxy compound containing at least 5%, expressed in terms of aluminum atom, of a portion insoluble in a mixed solvent of toluene and hexane in a ratio by volume of 2:5 at 30° C. or lower; and a catalyst for producing a polymer comprising any of the above organic aluminoxy compounds and a transition metal compound.

Abstract: An organic aluminoxy compound which shows .sup.27 Al nuclear magnetic resonance spectrum (.sup.27 Al-NMR spectrum) having an A.sub.1 /A.sub.2 ratio of at most 0.1, wherein A.sub.1 is area of a region encompassed by a segment of a line which connects a local minimum point existing between a continuous curve "a" containing a peak appearing at around 150 ppm and a continuous curve "b" containing a peak appearing at around 60 ppm to the point where the above curve "b" comes into contact with the base line and also by the above curve "b" and A.sub.2 is area of a region encompassed by the above curves "a" and "b" and also by the base line; an organic aluminoxy compound containing at least 5%, expressed in terms of aluminum atom, of a portion insoluble in a mixed solvent of toluene and hexane in a ratio by volume of 2:5 at 30.degree. C. or lower; and a catalyst for producing a polymer comprising any of the above organic aluminoxy compounds and a transition metal compound.

Abstract: An organic aluminoxy compound which shows .sup.27 Al nuclear magnetic resonance spectrum (.sup.27 Al-NMR spectrum) having an A.sub.1 /A.sub.2 ratio of at most 0.1, wherein A.sub.1 is area of a region encompassed by a segment of a line which connects a local minimum point existing between a continuous curve "a" containing a peak appearing at around 150 ppm and a continuous curve "b" containing a peak appearing at around 60 ppm to the point where the above curve "b" comes into contact with the base line and also by the above curve "b" and A.sub.2 is area of a region encompassed by the above curves "a" and "b" and also by the base line; an organic aluminoxy compound containing at least 5%, expressed in terms of aluminum atom, of a portion insoluble in a mixed solvent of toluene and hexane in a ratio by volume of 2:5 at 30.degree. C. or lower; and a catalyst for producing a polymer comprising any of the above organic aluminoxy compounds and a transition metal compound.