三氟化钴（化学式：CoF3），室温下为不稳定的浅棕色易潮解固体，密度为3.88g/mL（25℃），溶于水放出氧气，是很常用的氟化剂。在CO2气流中加热到250℃时，开始放出F2，在350℃时，则完全转变为CoF2。
Cobalt trifluoride (chemical formula: CoF3) is an unstable light brown deliquescent solid with a density of 3.88g/mL (25 ~C) at room temperature. It dissolves in water and emits oxygen. It is a commonly used fluorinating agent. When heated to 250 C in the CO2 gas stream, F2 begins to emit, and completely converts to CoF2 at 350 C.
与氟同族的氯也可生成钴的二元化合物，但很不稳定，三氧化二钴溶于盐酸时便会有氯气放出。溴化钴及碘化钴从未制得。
Chlorine of the same group with fluorine can also form cobalt binary compounds, but it is very unstable. When cobalt trioxide dissolves in hydrochloric acid, chlorine gas will be released. Cobalt bromide and cobalt iodide have never been prepared.
三氟化钴可以与许多金属或非金属单质反应生成相应的氟化物，自身被还原为二氟化钴。三氟化钴也有水合物，CoF3·3.5H2O，但结构尚不清楚。
Cobalt trifluoride can react with many metallic or non-metallic elements to form corresponding fluoride, which is reduced to cobalt difluoride. Cobalt trifluoride also has hydrate, CoF3.3.5H 2O, but its structure is not yet clear.
用三氟化钴氟化有机化合物时，首先用二氟化钴与氟气在300℃左右反应生成三氟化钴，然后引入有机反应物与三氟化钴反应。三氟化钴被还原后生成的二氟化钴可以循环使用。氟化反应包含单电子转移及碳正离子中间体机理：
When cobalt trifluoride is used to fluorinate organic compounds, cobalt trifluoride is first synthesized by reaction of cobalt difluoride with fluorine gas at about 300 C, and then organic reactants are introduced to react with cobalt trifluoride. The cobalt difluoride produced by reduction of cobalt trifluoride can be recycled. The fluorination reaction includes the mechanism of single electron transfer and carbon ion intermediates.