We have used a simple semi-analytic — momentum transfer theory (MTT) to develop negative halogen ions/noble gases momentum transfer integral cross sections based on the available data for reduced mobility at 300 K as a function of E/N. The unfolded cross sections were validated or further improved by assuring a good agreement between our Monte Carlo (MC) calculated transport data and the available experimental results. The data are produced with an aim to provide plasma modellers with cross section data and transport coefficients. We have also calculated the net rates of elastic scattering and detachment.