Its atomic radius is 0.248 nm and the (+1) ionic radius is 0.148 nm. In the solid state Rubidium has a body-centered cubic crystal structure with a = 0.562 nm and a nearest neighbor distance of 0.478 ...

[W3AXL] picked up a rubidium reference oscillator on eBay at ... where he actually converts the GPS-discipline oscillator to use the new atomic clock. We’ve seen this done before, of course.

He’s made a real-time-clock module controlled by a rubidium frequency standard ... but among them have been a few based upon atomic standards. More than one has been used as a lab reference ...