Re: How do covalent network solids end?

According to the Stanford University thesis of Bradford Pate looking at 
diamond cleaved under ultrahigh vacuum with Low Energy Electron 
Diffraction, stable diamond surface terminates in C-H.  Silicon does the 
same thing in hydrofluoric acid bath, Si-H rather than Si-F expected on 
purely bond strength arguments.

 http://tph.tuwien.ac.at/~kern/diss/node60.html
B. B. Pate, Surf. Sci. 165 83 (1986)
Physica 117B & 118B 783 (1983)
 
The Si-H surface is important to the quality of semiconductor devices.  
Si-D (deutrerium) gives you several tens of degrees higher maximum 
operating temprature.

Uncle Al!