Temperature-dependent Raman study of CaCu(HCOO)(4) and Ca2Cu(HCOO)(6) crystals

Unpolarized Raman spectra of policrystalline samples of calcium (II)-copper (II) formate [CaCu(HCOO)(4)] and dicalcium (II)-copper (II) formate [Ca2Cu (HCOO)(6)] were recorded and analyzed in the temperature range from 30 to 3 00 K, The observed modes at 300 K were assigned on the basis of formate gro up vibrations and correlations with previous data reported for other format e compounds, The splitting of the internal HCOO modes agrees with the group theory predictions. No changes either in the wavenumber or intensity of Ra man modes were observed when the temperature of the samples was cooled to 3 0 K, This indicates that these compounds do no exhibit any phase transforma tion in the temperature range investigated. (C) 2000 Academic Press.