alpha-Ni(H2O)(6)center dot SO4 and its selenate derivative exhibit chirality only in the solid-state. We have observed, for the first time, a sign inversion of CD (circular dichroism) in the (3)A(2g) -> T-3(1g)(P) Ni(II) d-d transition at near liquid nitrogen temperatures. The novel finding was achieved by building a new cooling unit to a solid-state specialized Universal Chiroptical Spectrophotometer (UCS-1) [R. Kuroda, T. Harada, Y. Shindo, Rev. Sci. Instrum. 72 (2001) 3802.] and by formulating an analytical procedure to obtain artifact-free CD signals based on the Mueller matrix method. The sign inversion is remarkable as the crystal structure hardly changes from 300 to 100 K. The origin of the sign inversion is discussed. (c) 2008 Elsevier B.V. All rights reserved.