The present invention relates to a catalyst system for oxidation of o-xylene and/or naphthalene to phthalic anhydride (PA), comprising a plurality of catalyst zones arranged in succession in the reaction tube, which have been produced using antimony trioxide comprising a noticeable proportion of senarmontite wherein some of the primary crystallites have a size of less than 200 nm. The present invention further relates to a process for gas phase oxidation, in which a gas stream comprising at least one hydrocarbon and molecular oxygen is passed through a catalyst system which comprises a plurality of catalyst zones arranged in succession in the reaction tube and which has been produced using an antimony trioxide comprising a noticeable proportion of senarmontite wherein some of the primary crystallites have a size of less than 200 nm.

An inorganic ion adsorbent represents by Formula (1) below, wherein in powder X-ray diffraction measurement using CuK radiation, the diffraction intensity of tetragonal tin oxide is at least 3% relative to the diffraction intensity of antimony pentoxide (Sb.sub.2O.sub.5.Math.2H.sub.2O), and the diffraction intensity of cubic antimony pentoxide is no greater than 40% relative to the diffraction intensity of antimony pentoxide (Sb.sub.2O.sub.5.Math.2H.sub.2O),
SnO.sub.2.Math.aSb.sub.2O.sub.5.Math.nH.sub.2O(1)
wherein in the Formula, a denotes a number that satisfies 0.2a4 and n denotes hydration number and is 0 or a positive number.

The present invention relates to a catalyst system for oxidation of o-xylene and/or naphthalene to phthalic anhydride (PA), comprising a plurality of catalyst zones arranged in succession in the reaction tube, which has been produced using antimony trioxide consisting predominantly of the senarmontite modification of which all primary crystallites have a size of less than 200 nm. The present invention further relates to a process for gas phase oxidation, in which a gas stream comprising at least one hydrocarbon and molecular oxygen is passed through a catalyst system which comprises a plurality of catalyst zones arranged in succession in the reaction tube and which has been produced using an antimony trioxide consisting predominantly of the senarmontite modification with a median primary crystallite size of less than 200 nm.

The present invention relates to a catalyst system for oxidation of o-xylene and/or naphthalene to phthalic anhydride (PA), comprising a plurality of catalyst zones arranged in succession in the reaction tube, which have been produced using antimony trioxide comprising a noticeable proportion of senarmontite wherein some of the primary crystallites have a size of less than 200 nm. The present invention further relates to a process for gas phase oxidation, in which a gas stream comprising at least one hydrocarbon and molecular oxygen is passed through a catalyst system which comprises a plurality of catalyst zones arranged in succession in the reaction tube and which has been produced using an antimony trioxide comprising a noticeable proportion of senarmontite wherein some of the primary crystallites have a size of less than 200 nm.

Provided are an iodine-containing metal compound, a composition for depositing a metal-containing thin film including the same, and a method of manufacturing a metal-containing thin film using the same. Since the composition for depositing a thin film according to one embodiment is present in a liquid state at room temperature, it has excellent storage and handling properties, and since the composition has high reactivity, a metal thin film may be efficiently formed using the composition.