Which of the following statements is false ?

${\mathrm{Na}}_2{\mathrm{Cr}}_2{\mathrm{O}}_{7 }\mathrm{is} \mathrm{a} \mathrm{primary} \mathrm{standard} \mathrm{in} \mathrm{volumetric} \mathrm{analysis}.$

${\mathrm{CrO}}_4^{-2 }\mathrm{is} \mathrm{tetrahedral} \mathrm{in} \mathrm{shape}$

${\mathrm{Na}}_2{\mathrm{Cr}}_2{\mathrm{O}}_7 \mathrm{is} \mathrm{less} \mathrm{soluble} \mathrm{than} {\mathrm{K}}_2{\mathrm{Cr}}_2{\mathrm{O}}_7$

${\mathrm{Cr}}_2{\mathrm{O}}_7^{-2 }\mathrm{has} \mathrm{a} \mathrm{Cr}-\mathrm{O}-\mathrm{Cr} \mathrm{bond}$