Convert from X unit to verst

Unit Definition (X unit)
The X-unit (symbol xu) is a unit of length formerly used to measure the wavelength of X-rays and gamma rays. The X-unit is approximately 1.0021×10-13 metre. Defined by the Swedish physicist Karl Manne Georg Siegbahn (1886-1978) in 1925, the X-unit could not at that time be measured directly; the definition was instead made in terms of the spacing between planes of the calcite crystals used in the measuring apparatus.

Unit Definition (verst)
An obsolete Russian unit of length. It is defined as being 500 sazhen long, which makes a verst equal to 3500 feet (1066.8 metres).