Impeller of a turbo compressor, for rotation about an axis, comprising an inlet cross section for the substantially axial inflow of a process fluid into the impeller, comprising an outlet cross section for the substantially radial exit of the process fluid from the impeller, comprising a wheel disc which defines a hub-side deflection contour from the axial flow direction into the radial flow direction, comprising blades which are attached to the wheel disc and define flow channels from a leading edge as far as a trailing edge in the circumferential direction at least over a part of the flow path of the process fluid through the impeller, each blade defining a linear inner track extending in the flow direction on a proximal extent end edge with respect to the wheel disc, in such a way that there are orthogonally identical spacings from a blade surface on a pressure side and a suction side of the blade on both sides of the inner track, the blade on a distal extent end edge with respect to the wheel disc defining a linear outer track extending in the flow direction, in such a way that there are orthogonally identical spacings from the blade surface on the pressure side and on the suction side of the blade on both sides of the outer track, a relative blade length for each position on a track which is an inner track or outer track being defined in each case as a proportion of the blade length situated upstream of this position with respect to the total blade length of the relevant track, namely the inner track or the outer track, a meridional angle for each position of a track being defined as the angle enclosed upstream between a meridional plane through this position and a tangent on the track, there being a local extreme of the meridional angle of the inner track in the range between 10% and 90% of the relative blade length, the blade leading edge configuring an angle of between 35° and 45° with a radial plane, characterized in that, in the range between 10% and 90% of the relative blade lengths, the maximum difference (DLTM) between the inner track and the outer track for a certain position along the relative blade lengths of the meridional angle is between 10° and 25°, the maximum difference (DLTM) between the inner track and the outer track along the relative blade lengths of the meridional angle lying in the range between 15% and 45% of the relative blade lengths. comprising an outlet cross section for the substantially radial exit of the process fluid from the impeller, comprising a wheel disc which defines a hub-side deflection contour from the axial flow direction into the radial flow direction, comprising blades which are attached to the wheel disc and define flow channels from a leading edge as far as a trailing edge in the circumferential direction at least over a part of the flow path of the process fluid through the impeller, each blade defining a linear inner track extending in the flow direction on a proximal extent end edge with respect to the wheel disc, in such a way that there are orthogonally identical spacings from a blade surface on a pressure side and a suction side of the blade on both sides of the inner track, the blade on a distal extent end edge with respect to the wheel disc defining a linear outer track extending in the flow direction, in such a way that there are orthogonally identical spacings from the blade surface on the pressure side and on the suction side of the blade on both sides of the outer track, a relative blade length for each position on a track which is an inner track or outer track being defined in each case as a proportion of the blade length situated upstream of this position with respect to the total blade length of the relevant track, namely the inner track or the outer track, a meridional angle for each position of a track being defined as the angle enclosed upstream between a meridional plane through this position and a tangent on the track, there being a local extreme of the meridional angle of the inner track in the range between 10% and 90% of the relative blade length, the blade leading edge configuring an angle of between 35° and 45° with a radial plane, characterized in that, in the range between 10% and 90% of the relative blade lengths, the maximum difference (DLTM) between the inner track and the outer track for a certain position along the relative blade lengths of the meridional angle is between 10° and 25°, the maximum difference (DLTM) between the inner track and the outer track along the relative blade lengths of the meridional angle lying in the range between 15% and 45% of the relative blade lengths.