[salazar888]

1. I'm trying to perform a back-of-the-envelope molecular orbital analysis of a tungsten hydride complex, (WH6) and I haven't been able to find an intuitive or basic definition for a "d0 complex". Every time I read an article about a d0 complex they tangentially mention them and then jump into the problem.

-What is the definition of a d0 complex?

The attempt at a solution: I thought it referred to any complex where the d orbital electrons do not directly participate in the bonding between the metal and its ligands. I just want a pure definition. Thank you so much.

2. If the point group is c3v rather than Oh, what is the main reason for the distorted geometry of the complex?

[Yakimikku]

The "d-n", n = a number from 0-10, specifies the d-electron count for a particular metal. Thus, "d0" implies that that the metal (in your case tungsten) has no d electrons. Knowing that you can determine the oxidation state of W.

I'm not so sure about your second question (I'd have to look into it). Hydrides exhibit a strong trans effect, so my first hunch would be that it causes a facial set of hydrides with elongated bonds (WH^a₃H^b₃ with distance W-H^a < W-H^b). The geometry of this would be c3v.