Abstract
The nine systems Ti-S, Ti-Se, Ti-Te, Zr-S, Zr-Se, Zr-Te, Hf-S, Hf-Se, and Hf-Te have been investigated by X-ray techniques for the occurrence of phases between the compositions AXmax. and AX. Compounds were prepared from materials of high purity by direct synthesis from the elements, or by degradation of a higher to a lower phase. All manipulation was done in dry argon. Several new compounds are reported, some major differences in the type of phase formed by zirconium and hafnium are noted, and a different interpretation of the X-ray data for the AX3 compounds is discussed.