Figure 4.

(a) Typical NH₄H₂PO₄ crystal structure representation from a filtered data set. All hydrogen atoms were found and all the ADPs are reasonable after anisotropic refinement. (b), (c) Two typical NH₄H₂PO₄ crystal structures obtained from unfiltered data sets. The refinement was unable to locate all the hydrogen atoms around the nitro­gen atom or to obtain reasonable displacement parameters for the nitro­gen atom. The dotted lines represent the hydrogen bond between the hydrogen atom and the oxygen atom. White – hydrogen; blue – nitro­gen; purple – phosphate; red – oxygen.