I've got a citation where the authors name includes Š. LaTeX gives an "! Package inputenc Error: Invalid UTF-8 byte sequence." on this, fine, I'm used to that, so I replace it with \v{S}. That just gives me a v in the output. But \v{z} works just fine.
MWE:
\documentclass[]{article}
\usepackage[utf8]{inputenc} %Allows UTF8 input.
\begin{filecontents}{UTF8.bib}
@Article{UTF8,
author ="Chen, Teng-Hao and Lee, Semin and Flood, Amar H. and Miljanić, Ognjen Š.",
title ="How to print a crystal structure model in 3D",
journal ="CrystEngComm",
year ="2014",
}
@Article{LaTeX,
author ="Chen, Teng-Hao and Lee, Semin and Flood, Amar H. and Miljanić, Ognjen \v{S}.",
title ="How to print a crystal structure model in 3D",
journal ="CrystEngComm",
year ="2014",
}
@article{TeachingReview,
author = "Gra{\v{z}}ulis, Saulius and Sarjeant, Amy Alexis and Kantardjieff, Katherine A and et al..",
title = "{Crystallographic education in the 21st century}",
journal = "Journal of Applied Crystallography",
year = "2015",
}
\end{filecontents}
\usepackage[utf8]{inputenc}
\usepackage[super,sort&compress,comma]{natbib}
\usepackage[T1]{fontenc}
\usepackage{natmove}
\begin{document}
Oddly Miljanić, Ognjen Š. works fine in the body of the text.\cite{UTF8}
If I encode the name in LaTeX it works in body text: Miljanić, Ognjen \v{S}.\cite{LaTeX}
But REALLY oddly Gra{\v{z}}ulis, Saulius works everywhere.\cite{TeachingReview}
\bibliography{UTF8}
\bibliographystyle{abbrvnat} %the RSC's .bst file
\end{document}

{\v S}not\v{S}– David Carlisle Sep 06 '18 at 18:42\v{z}andćonly work as they are not used at a place where bibtex needs to separate a single letter – David Carlisle Sep 06 '18 at 18:56{\v S}part but I'm not sure that this is a duplicate as there is the additional issue of why multi-byte characters work mid-word but not at the start where bibtex breaks apart the utf-8 stream. – David Carlisle Sep 06 '18 at 20:38