Crystal Growth of the S$=$\textbf{1/2 Antiferromagnet K}$_{\mathrm{\mathbf{2}}}$\textbf{PbCu(NO}$_{\mathrm{\mathbf{2}}}$\textbf{)}$_{\mathrm{\mathbf{6}}}$\textbf{ Elpasolite }

The elpasolite \textit{K2PbCu(NO2)6 }is known for its two structural transitions at 281 K and 273 K. Single crystals of \textit{K2PbCu(NO2)6 }have been grown in aqueous solution, but the rapid nucleation rate and convective transport renders it difficult to obtain large high quality single crystals. We developed a gel method to grow $K_{2}$\textit{PbCu(NO}$_{2})_{6}$ Elpasolite with sizes up to 5x5x5 mm$^{\mathrm{3}}$, suitable for neutron diffraction measurements. Susceptibility measurements clearly show that the Jahn-Teller distortions at 286K and 273K with associated orbital ordering produce a linear chain Heisenberg antiferromagnetic system. The intrachain interaction strength has been derived from a Bonner-Fisher analysis that yielded a value of 5.4K.