Characterization and reproducibility of some Chevrel-compound samples: Sn${\mathrm{Mo}}_6$${\mathrm{S}}_8$ and $\mathrm{Pb}{\mathrm{Mo}}_x{\mathrm{S}}_8 (x=6.00,6.20, \mathrm{and} 6.35)$

A series of samples of Sn${\mathrm{Mo}}_6$ ${\mathrm{S}}_8$ and $\mathrm{Pb}{\mathrm{Mo}}_x{\mathrm{S}}_8 (x=6.00,6.20, \mathrm{and} 6.35)$ were made with standardized techniques. The samples were characterized with x-ray diffraction, optical microscopy, scanning electron microscopy, and electron microprobe work. The superconducting transition temperatures of six Sn${\mathrm{Mo}}_6$ ${\mathrm{S}}_8$ sampels had a standard deviation of 39 mK. The superconducting transition temperatures of four $\mathrm{Pb}{\mathrm{Mo}}_x{\mathrm{S}}_8$ samples had a standard deviation of 20 mK for $x=6.00,16$ mK for $x=6.35, \mathrm{and} 165$ mK for $x=6.20\mathrm{}$. These standard deviations are about a factor of 5 less than those in the literature for the $x=6.00\mathrm{} \mathrm{and} 6.35$ materials and slightly less than those in the literature for the $x=6.20\mathrm{}$ material. The temperature dependence of the upper critical field, $H_{c2}$, was measured up to 30 kG. The graphs of $H_{c2}\mathrm{}\left(T\right)\mathrm{}$ show a positive curvature below 10 kG for all of the samples.