The decays $B^0_s rightarrow J/psi pi^+pi^- K^+ K^-$ are studied using a data set corresponding to an integrated luminosity of 9fb$^{-1}$, collected with the LHCb detector in proton-proton collisions at centre-of-mass energies of 7, 8 and 13TeV. The decays $B^0_s rightarrow J/psi K^{ast0} bar{K}^{ast0}$ and $B^0_s rightarrow chi_{c1}(3872)K^+K^-$, where the $K^+K^-$ pair does not originate from a $phi$ meson, are observed for the first time. Precise measurements of the ratios of branching fractions between intermediate $chi_{c1}(3872)phi$, $J/psi K^{ast0}bar{K}^{ast0}$, $psi(2S)phi$ and $chi_{c1}(3872)K^+K^-$ states are reported. A structure, denoted as $X(4740)$, is observed in the $J/psiphi$ mass spectrum and, assuming a Breit-Wigner parameterisation, its mass and width are determined to be begin{eqnarray*} m_{X(4740)} & = & 4741 pm 6 pm 6,{mathrm{MeV}}/c^2 ,, Gamma_{X(4740)} & = & 53 pm 15 pm 11,{mathrm{MeV}} ,, end{eqnarray*} where the first uncertainty is statistical and the second is systematic. In addition, the most precise single measurement of the mass of the $B^0_s$ meson is performed and gives a value of $$ m_{B^0_s} = 5366.98 pm 0.07 pm 0.13,{mathrm{MeV}}/c^2,. $$
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