4. Densities and Other Parameters Related to the Physical Properties of the Different Glasses.

parameter	Nd	1SnNd	3SnNd	5SnNd	7SnNd	9SnNd
density, ρ (g/cm3)	3.674	3.718	3.696	3.694	3.709	3.700
average molar mass, M av (g/mol)	149.47	149.32	148.99	148.71	148.37	148.00
molar volume, V m (cm3/mol)	40.68	40.16	40.31	40.26	40.01	39.99
Nd3+ concentration, N Nd (×1020 ions/cm3)	2.960	2.999	2.988	2.992	3.011	3.011
Nd3+–Nd3+ mean distance, d Nd–Nd (Å)	15.00	14.94	14.96	14.95	14.92	14.92
Sn2+ concentration, N Sn (×1020 ions/cm3)		1.167	3.683	5.848	8.630	11.586
Sn2+–Sn2+ mean distance, d Sn–Sn (Å)		20.47	13.95	11.96	10.50	9.52
Sn2+–Nd3+ mean distance, d Sn–Nd (Å)		13.58	11.44	10.42	9.51	8.82