Cerium (III) oxalate is produced by precipitating cerous ions with oxalic acid under controlled pH and temperature, yielding a well-defined hydrate that can be calcined to cerous oxide or further converted to other salts. It serves both as a product and as an intermediate for oxide producers seeking tight morphology control. Most capacity is integrated with rare-earth separation plants that can flex among oxalate, carbonate, and hydroxide routes depending on downstream demand.