Optically clear single crystals of Na 2 SbBF 8 are grown by the slow evaporation method. The crystals are subjected to microhardness studies and the variation of the microhardness with the applied load is studied. Corrections to the diagonal lengths of indentations are introduced to fit Kick's law. The correction is found to be negative for Na 2 SbBF 8 , whose value of the work-hardening coefficient n is greater than 2, and positive for other sodium fluoroantimonate crystals of n is less than 2. An attempt has also been made to study the deviation of the work-hardening coefficient n from a value of 2.