The starting ingredients are the same as for the synthesis of (Nb 4 Se 15 I 2 )I 2 . Elements were ground in an agate mortar with a molar ratio of Nb (99.8%, powder) : Se (99.999%, ground shots) : I (99.8%, crystalline solid) = 2 : 8 : 10.3. The excess 0.3 iodine was intentionally added to compensate for the loss from sublimation, and the ratio of iodine was larger than any known Nb-Se-I ternary compounds, to ensure enough iodine was available to act as the transport agent. The total sample mass was about 0.9 g. After fully grinding with a pestle, the mixture tended to form a porous, loosely-bound agglomerate, and Nb powder did not stick to the surface of the mortar.