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Emission and absorption features from C-like ions serve as temperature and density diagnostics of astrophysical plasmas. $R$-matrix electron-impact excitation data sets for C-like ions in the literature merely cover a few ions, and often only for the ground configuration. Our goal is to obtain level-resolved effective collision strength over a wide temperature range for C-like ions from \ion{N}{II} to \ion{Kr}{XXXI} (i.e., N$^{+}$ to Kr$^{30+}$) with a systematic set of $R$-matrix calculations. We also aim to assess their accuracy. For each ion, we included a total of 590 fine-structure levels in both the configuration interaction target and close-coupling collision expansion. These levels arise from 24 configurations $2l^3 nl^{\prime}$ with $n=2-4$, $l=0-1$, and $l^{\prime}=0-3$ plus the three configurations $2s^22p5l$ with $l=0-2$. The AUTOSTRUCTURE code was used to calculate the target structure. Additionally, the $R$-matrix intermediate coupling frame transformation method was used to calculate the collision strengths. We compare the present results of selected ions with archival databases and results in the literature. The comparison covers energy levels, transition rates, and effective collision strengths. We illustrate the impact of using the present results on an \ion{Ar}{xiii} density diagnostic for the solar corona. The electron-impact excitation data is archived according to the Atomic Data and Analysis Structure (ADAS) data class adf04 and will be available in OPEN-ADAS. The data will be incorporated into spectral codes, such as CHIANTI and SPEX, for plasma diagnostics., Comment: accepted to A&A

We have carried-out parallel intermediate-coupling frame transformation R-matrixcalculations for electron-impact excitation amongst the 204 close-coupling levels of the 2s x 2p y (x + y = 3), 2s 2 {3,4}l ,2 s2p{3,4}l, and 2p 2 3l configurations for all boron-like ions from C + to Kr 31+ . We have also included the configuration interaction due to the 2p 2 4l ,2 s3l3land 2p3s3l configurations. A detailed comparison has been made of the target structure and excitation data for four specific ions (viz., Ne 5+ ,A r 13+ ,F e 21+ and Kr 31+ )t hat span the sequence, so as to assess the accuracy over the entire sequence. Effective collision strengths (Ys) are presented at temperatures ranging from 2 ×10 2 (z +1) 2 Kt o 2×10 6 (z +1) 2 K( wherez is the residual charge of the ions, i.e. Z −5). Detailed comparisons for the (effective) collision strengths (Ys) Ω are made with the results of previous calculations for the four representative ions. Furthermore, we examine the iso-electronic trends of the effective collision strengths as a function of temperature.