KNb4O6
Sugimoto, W.Mimuro, K.Sugahara, Y.Kuroda, K.
Journal of the Ceramic Society of Japan (1999) 107, 318-321
a=4.1396(6)Å b=4.1396(6)Å c=8.256(1)Å
α=90° β=90° γ=90°
KNbO3
a=3.9807(7)Å b=5.688(1)Å c=5.711(1)Å