OP wonders:
From Shriver Atkin's Inorganic Book, the Latimer diagram of Ruthenium compounds in basic medium does not exist. I wonder what happen to the ruthenium compound in basic medium?
OP also wonders is there Latimer diagram for ruthenium in base medium. I think there are no Latimer diagram of Ruthenium compounds in basic medium can be found in internet, to my knowledge. However, what happen to the ruthenium compounds in basic medium can be determined by analyzing Pourbaix diagram of ruthenium. For more details about Pourbaix diagram can be found in here. Basically it is a map of the predominant equilibrium species of an aqueous electrochemical system (mostly based on thermochemical data), which is useful for identifying which materials/species are present/stable according to $\mathrm{pH}$ value.
A resent paper discusses few Pourbaix diagrams in different concentrations of ruthenium solutions (Ref.1). For example, Pourbaix diagram for $\pu{1 \times 10^{-4} mol L-1}$ solution of $\ce{Ru^3+}$ within $\mathrm{pH}$ range of 0-14:
According to the diagram, $\ce{Ru^3+}$ (as in $\ce{RuCl3}$) does not exist in $\mathrm{pH}$ above 2. That's probably why different chemist studying ruthenium catalysts use different methods to make $\ce{Ru(OH)3}$ or $\ce{Ru(OH)_x}$ (either is solid and insoluble in water) on a supporting material. For example, Ref.2 states following method:
The supported $\ce{Ru(OH)_x}$ catalysts were prepared by the reaction of $\ce{TiO2}$ (or $\ce{Al2O3}$) with $\ce{RuCl3}$ in aqueous medium followed by the treatment with $\ce{NaOH}$. The powder $\ce{TiO2}$ (or $\ce{Al2O3}$) ($\pu{2.0 g}$) pretreated at $\pu{550 ^\circ C}$ for $\pu{3 h}$ was vigorously stirred with $\pu{60 mL}$ of an aqueous solution of $\ce{RuCl3}$$(\pu{8.3 mM}$, $\mathrm{pH}$ ca. 2.0$)$ at room temperature. After $\pu{15 min}$, the $\mathrm{pH}$ of the solution was adjusted to 13.2 by addition of an aqueous solution of $\ce{NaOH}$ ($\pu{1.0 M}$) and the resulting slurry was stirred for $\pu{24 h}$. The solid was then filtered off, washed with a large amount of water (ca. $\pu{4.0 L}$), and dried in vacuo to afford supported ruthenium hydroxide catalysts.
You can prepare $\ce{Ru(OH)_x}$ without a solid support using the same procedure in 80% yield based on $\ce{RuCl3}$ (Re.2; supplementary material).
References:
- Igor Povar and Oxana Spinu, "Ruthenium redox equilibria: 3. Pourbaix diagrams for the systems $\ce{Ru-H2O}$ and $\ce{Ru-Cl^--H2O}$," Journal of Electrochemical Science and Engineering2016, 6(1), 145-153 (DOI: 10.5599/jese.229)(PDF).
- Kazuya Yamaguchi, Jung Won Kim, Jinling He, and Noritaka Mizuno, "Aerobic alcohol oxidation catalyzed by supported ruthenium hydroxides," Journal of Catalysis2009, 268(2), 343-349 (DOI: https://doi.org/10.1016/j.jcat.2009.10.004).