Cesium has applications in vacuum tubes, atomic clocks, petroleum exploration and electronics. The diversity of uses for cesium are a result of its high number of isotopes, the most of any element.
Cesium's tendency to bond easily to oxygen makes it a good getter in vacuum tubes. A getter is an element that binds to and removes trace gases. Cesium is also useful in photoelectric cells due to its ability to convert light into electron flow. Cesium vapor is often a component of vapor lamps and lasers.
The cesium-133 isotope is part of some of the most accurate atomic clocks in the world. Cesium clocks provide a standard for the measurement of time. Current estimates place the accuracy of contemporary cesium clocks at 2 seconds every 66 million years; this means that a cesium clock set during the time of the dinosaurs is only inaccurate by 2 seconds.
Cesium formate plays an important part in petroleum exploration as a drilling fluid. Drilling fluids lubricate drill parts and help provide stability to the well during drilling. Cesium is relatively non-toxic in comparison to other drilling fluids. While cesium is expensive, it is reclaimable and available for subsequent use. Cesium is also biodegradable.