measurement of resistance using the method of example 2 and a similar heating schedule 400 u00b0 200 u00b0 1 day 700 u00b0 300 u00b0 2 days 1200 u00b0 1000 u00b0 3 days an elemental mixture corresponding to the stoichiometry la 2 zr 0 9 nb 0 1 s 5 was reacted the product consisted of red brown microcrystals which except for a few extra lines could be indexed on the basis of an orthorhombic unit cell a 11 504 b 7 397 c 8 221 of the type previously described the small but distinct difference in cell parameters from that of example 2 la 2 zrs 5 indicates the incorporation of some niobium into the la 2 zrs 5 lattice in the same manner as described above other elemental mixtures of a rare earth metal zirconium or hafnium and either sulfur or selenium were reacted to yield the product m 2 m 39 x 5 having the characteristic x ray pattern described for the previous examples and typified in table i table ii gives the orthorhombic lattice parameters for each pattern the same characteristic phase results as the major product whether the starting mixture has the appropriate composition m 2 m 39 x 5 or the rare earth poor ratio.