Co7Er2
Ostertag, W.
Journal of the Less-Common Metals (1967) 13, 385-390
a=4.973Å b=4.973Å c=36.11Å
α=90° β=90° γ=120°
Co3Er
Transactions of the Metallurgical Society of Aime (1967) 239, 690-694
a=4.978Å b=4.978Å c=24.25Å