Often, single-crystal X-ray diffraction analysis determines the non-H atoms first, and eventually puts hydrogen atoms "as riding" on idealized positions in respect to heavier atoms (e.g., C, O, N), because the latters are easier to localize in the Fourier maps. This then considers both distance and geometry (e.g., 0.93 Å for an H attached to a sp-hybridized C) and temperature during the experiment, determined by other experiments (e.g., neutron diffraction).
Is there a particular name for a sum / Hill formula where the hydrogens are omitted, for example, when stating glucose as $\ce{C6O6}$ instead of a complete $\ce{C6H12O6}$ to describe just the backbone of the molecule?
