A radiation-sensitive composition contains: a polymetalloxane including a structural unit represented by formula (1); a radiation-sensitive acid generator; and a solvent. In the following formula (1), M represents a germanium atom, a tin atom or a lead atom; Ar.sup.1 represents a substituted or unsubstituted aryl group having 6 to 20 ring atoms or a substituted or unsubstituted heteroaryl group having 5 to 20 ring atoms; R.sup.1 represents a monovalent organic group having 1 to 20 carbon atoms, a hydrogen atom, a halogen atom or a hydroxy group; and n is 2 or 3. ##STR00001##

A radiation-sensitive composition contains: a polymetalloxane including a structural unit represented by formula (1); a radiation-sensitive acid generator; and a solvent. In the following formula (1), M represents a germanium atom, a tin atom or a lead atom; Ar.sup.1 represents a substituted or unsubstituted aryl group having 6 to 20 ring atoms or a substituted or unsubstituted heteroaryl group having 5 to 20 ring atoms; R.sup.1 represents a monovalent organic group having 1 to 20 carbon atoms, a hydrogen atom, a halogen atom or a hydroxy group; and n is 2 or 3. ##STR00001##

A modified solid polyalkylaluminoxane is provided, which is capable of providing α-olefin suppressing adhesion of any polymer produced as a by-product onto the reactor wall and the stirrer, and which is capable of providing a highly active olefin oligomerization reaction catalyst. An olefin oligomerization reaction catalyst containing the modified solid polyalkylaluminoxane is also provided. The modified solid polyalkylaluminoxane for olefin oligomerization reactions contains structural units represented by general formula (a) and structural units represented by general formula (b), whose median diameter is equal to or larger than 0.1 μm and equal to or smaller than 50 μm,

##STR00001##

in which R′ in the general formula (a) represents an alkyl group having 1 to 20 carbon atoms, and R″ in the general formula (b) represents a halogenated alkoxy group having 1 to 20 carbon atoms or a halogenated aryloxy group having 6 to 20 carbon atoms.

A modified solid polyalkylaluminoxane is provided, which is capable of providing α-olefin suppressing adhesion of any polymer produced as a by-product onto the reactor wall and the stirrer, and which is capable of providing a highly active olefin oligomerization reaction catalyst. An olefin oligomerization reaction catalyst containing the modified solid polyalkylaluminoxane is also provided. The modified solid polyalkylaluminoxane for olefin oligomerization reactions contains structural units represented by general formula (a) and structural units represented by general formula (b), whose median diameter is equal to or larger than 0.1 μm and equal to or smaller than 50 μm,

##STR00001##

in which R′ in the general formula (a) represents an alkyl group having 1 to 20 carbon atoms, and R″ in the general formula (b) represents a halogenated alkoxy group having 1 to 20 carbon atoms or a halogenated aryloxy group having 6 to 20 carbon atoms.

A polymetalloxane is described having a constituent unit represented by the following general formula (1):

##STR00001##

wherein R.sup.1, R.sup.2, R.sup.3, M a, b and m are as defined.

A polymetalloxane is described having a constituent unit represented by the following general formula (1):

##STR00001##

wherein R.sup.1, R.sup.2, R.sup.3, M a, b and m are as defined.

A method of producing a metal oxide fiber is described, including a spinning step of spinning a composition containing a polymetalloxane and an organic solvent to obtain a thread-like product; and a firing step of firing the thread-like product obtained in the spinning step at a temperature of 200° C. or higher and 2,000° C. or lower to obtain a metal oxide fiber, where the polymetalloxane has a repeating structure composed of a metal atom selected from the group consisting of Al, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, Y, Zr, Nb, Mo, Pd, Ag, In, Sn, Sb, Hf, Ta, W and Bi, and an oxygen atom and where the weight average molecular weight of the polymetalloxane is 20,000 or more and 2,000,000 or less.

A method of producing a metal oxide fiber is described, including a spinning step of spinning a composition containing a polymetalloxane and an organic solvent to obtain a thread-like product; and a firing step of firing the thread-like product obtained in the spinning step at a temperature of 200° C. or higher and 2,000° C. or lower to obtain a metal oxide fiber, where the polymetalloxane has a repeating structure composed of a metal atom selected from the group consisting of Al, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, Y, Zr, Nb, Mo, Pd, Ag, In, Sn, Sb, Hf, Ta, W and Bi, and an oxygen atom and where the weight average molecular weight of the polymetalloxane is 20,000 or more and 2,000,000 or less.

A radiation-sensitive composition contains: a polymetalloxane including a structural unit represented by formula (1); a radiation-sensitive acid generator; and a solvent. In the following formula (1), M represents a germanium atom, a tin atom or a lead atom; Ar.sup.1 represents a substituted or unsubstituted aryl group having 6 to 20 ring atoms or a substituted or unsubstituted heteroaryl group having 5 to 20 ring atoms; R.sup.1 represents a monovalent organic group having 1 to 20 carbon atoms, a hydrogen atom, a halogen atom or a hydroxy group; and n is 2 or 3.

A radiation-sensitive composition contains: a polymetalloxane including a structural unit represented by formula (1); a radiation-sensitive acid generator; and a solvent. In the following formula (1), M represents a germanium atom, a tin atom or a lead atom; Ar.sup.1 represents a substituted or unsubstituted aryl group having 6 to 20 ring atoms or a substituted or unsubstituted heteroaryl group having 5 to 20 ring atoms; R.sup.1 represents a monovalent organic group having 1 to 20 carbon atoms, a hydrogen atom, a halogen atom or a hydroxy group; and n is 2 or 3.