63 which we met in nitrogen, yttrium, vanadium and niobium, but not the "balloon," which we shall find with it in krypton and its congeners.

ARGON: Six arms of 99 atoms 594
Central tetrahedra 120
----
Total 714
----
Atomic weight 39.60
Number weight 714/18 39.66

Metargon

(

[Plate XX]

, 5, 6 and 7) again shows only an additional seven atoms in each arm.

METARGON: Six arms of 106 atoms 636
Central tetrahedra 120
----
Total 756
----
Atomic weight ----
Number weight 756/18 42

Krypton