Context : The mechanisms giving rise to diffuse radio emission in galaxy clusters , and in particular their connection with cluster mergers , are still debated .

Aims : We explore the internal dynamics of Abell 2254 , which has been shown to host a very clumpy and irregular radio halo .

Methods : Our analysis is mainly based on redshift data for 128 galaxies acquired at the Telescopio Nazionale Galileo .
We combine galaxy velocities and positions to select 110 cluster galaxies and analyze its internal dynamics .
We also use new ( g ^ { \prime } , r ^ { \prime } , i ^ { \prime } ) photometric data acquired at the Isaac Newton Telescope and ( V , i ^ { \prime } ) photometric data available in the Subaru Archive .
X-ray data from the XMM-Newton Science Archive are analyzed to study the hot gas component .

Results : We estimate the cluster redshift \left < z \right > = 0.177 , a high line-of-sight ( LOS ) velocity dispersion , \sigma _ { V } \sim 1350 km s ^ { -1 } , and the X-ray temperature kT \sim 6.4 keV .
Both our optical and X-ray analyses reveal a complex dynamical activity .
The analysis of the 2D galaxy distribution reveals the presence of two density peaks , one at the East and the other at the West .
Using the full 3D information we detect a high velocity ( \Delta V _ { rf,LOS } \sim 3000 km s ^ { -1 } ) , low mass ( \sigma _ { V } \sim 200 –500 km s ^ { -1 } ) group at the position of the 2D eastern peak .
For the main system we compute a velocity dispersion \sigma _ { V } \sim 1000 –1200 km s ^ { -1 } .
In the assumption of a bimodal system we estimate a mass M _ { sys } = 1.5 –2.9 \times 10 ^ { 15 } h _ { 70 } ^ { -1 } M _ { \odot } .
The X-ray morphological analysis , based on power ratios , centroid shifts , and concentration parameter , confirms that Abell 2254 is a dynamically disturbed cluster .
The X-ray isophotes are elongated toward the eastern direction , in agreement with a merger in the post core-crossing phase .
A simple bimodal model finds that data are consistent with a bound , outgoing subcluster observed a few fractions of Gyr after the core crossing .
However , both optical and X-ray analyses suggest that the main system is , at its time , a non relaxed structure , indicating N-S as a possible direction for a past accretion .

Conclusions : We conclude that Abell 2254 , for its mass and merging structure , fits well among typical clusters with radio halos .
We shortly discuss as the particular irregularity of the radio halo might be linked to the complexity of the Abell 2254 structure .