Trying to get samples from this document to work, I made the following minimal document on WriteLaTeX here
\documentclass{beamer}
\usepackage{tikz-cd}
\begin{document}
\begin{frame}{Hello Commutative Diagrams}
\begin{tikzcd}
A \arrow{rd} \arrow{r}{\phi} & B \\
& C
\end{tikzcd}
\end{frame}
\end{document}
and get error on next-to-last line "Single ampersand used with wrong catcode."
I try removing the ampersands or prepending a backslash to them and get "No shape named tikz@f@1-2-2 is known."
I try leaving in the backslashes before the ampersands and wrapping the tikzcd in {...} and preceding it with a \matrix (m) [matrix of math nodes, row sep=3em, column sep=3em,ampersand replacement=\&], which I snipped from another StackExchange answer, and I get "can't nest pgfmatrix environments yet."
I'm out of ideas.
tikz-cd/TikZ makes&active which doesn't work in aframeenvironment (forbeamerreasons). You need to use theampersand replacementoption (recommended) but without wrapping everything in a\matrixagain or use thefragileoption. Simply write\begin{tikzcd}[ampersand replacement=\&]and use\&instead of&. – Qrrbrbirlbel Jul 29 '13 at 13:57ampersand replacementoption be in my context -- it doesn't work in the context of the\matrix...command that I tried above. – Reb.Cabin Jul 29 '13 at 14:07\matrix; simply\begin{tikzcd}[ampersand replacement=\&] A \arrow{rd} \arrow{r}{\phi} \& B \ \& C \end{tikzcd}– Gonzalo Medina Jul 29 '13 at 14:08tikz-cduses already a\matrixinternally which would clash with yours. Simply specify a macro sequence (it can be (nearly) anything starting with a\) with theampersand replacementoption and use this at the place of the&s. The native macro would be\pgfmatrixnextcellif I remember correctly. – Qrrbrbirlbel Jul 29 '13 at 14:59