I What is the composition of the B1 phase in Cu-Zr alloy?

[Fabian_m9]

Hi,
I recently started studying materials science and I am looking at a particular alloy of Copper Zirconium.
I have identified a B1 phase and they call it a CuZr phase, which I 'm finding rather confusing. Initially I thought that CuZr meant that each unit cell in the lattice was composed of one copper atom and one zirconium atom.
After looking at a B1 structure of this material I realized that each unit cell in the lattice actually has 4 copper atoms and 4 zirconium atoms, therefore I am not sure why they call it a CuZr phase instead of Cu4Zr4.
Are they just expressing it as a ratio? So for every copper atom there is one zirconium atom?
Your help will be appreciated.

 

[Baluncore]

Are they just expressing it as a ratio?

Yes, and there may be other structures that also have a 1:1 ratio.