Disclosed are solid forms of 1-[(2-chloro-5-thiazolyl)methyl]-3-(3,5-dichlorophenyl)-2-hydroxy-9-methyl-4-oxo-4H-pyrido[1,2-a]pyrimidinium inner salt (Compound 1). Methods for the preparation of solid forms of Compound 1 and for the conversion of one solid form of Compound 1 into another are disclosed.Disclosed are compositions for controlling an invertebrate pest comprising a biologically effective amount of a solid form of Compound 1 and at least one additional component selected from the group consisting of surfactants, solid diluents and liquid carriers. Compositions comprising a mixture of a solid form of Compound 1 and at least one other nematocide, insecticide and/or fungicide are also disclosed.Also disclosed are methods for controlling invertebrate pests comprising applying to a plant or seed, or to the environment of the plant or seed, a biologically effective amount of a solid form of Compound 1.本發明揭露1-[(2-氯-5-噻唑基)甲基]-3-(3,5-二氯苯基)-2-羥-9-甲基-4-側氧-4H-吡啶[1,2-a]嘧啶鎓內鹽(化合物1)的固態型式。本發明並揭露製備化合物1固態型式及將化合物1之一種固態型式轉化成另一種固態型式的方法。本發明揭露用於防治無脊椎動物害蟲之組合物，包含生物有效量之化合物1的固態型式及至少一種額外組分，其係選自由界面活性劑、固體稀釋劑及液體載劑所組成之群組。本發明亦揭露包含化合物1的固態型式及至少一種其他殺線蟲劑、殺蟲劑及/或殺真菌劑之混合物的組合物。本發明亦揭露防治無脊椎動物害蟲的方法，包含施給植物或種子、或該植物或種子之環境一生物有效量的化合物1的固態型式。
