title: New thermodynamic data for CoTiO3, NiTiO3 and CoCO3 based on low-temperature calorimetric measurements.
abstract: The low-temperature heat capacities of nickel titanate (NiTiO3), cobalt titanate (CoTiO3), and cobalt carbonate (CoCO3) were measured between 2 and 300 K, and thermochemical functions were derived from the results. Our new data show previously unknown low-temperature lambda-shaped heat capacity anomalies peaking at 37 K for CoTiO3 and 26 K for NiTiO3. From our data we calculate standard molar entropies (298.15 K) for NiTiO3 of 90.9 ± 0.7 J mol-1 K-1 and for CoTiO3 of 94.4 ± 0.8 J mol-1 K-1. For CoCO3, we find only a small broad heat capacity anomaly, peaking at about 31 K. From our data, we suggest a new standard entropy (298.15 K) for CoCO3 of 88.9 ± 0.7 J mol-1 K-1.
authors.affiliation: Institut für Mineralogie, Westfälische-Wilhelms-Universität Münster, Corrensstr, 24, 48149 Münster, Germany. Stephan.klemme@uni-muenster.de.
authors.forename: Stephan
authors.initials: S
authors.lastname: Klemme
authors.forename: Wilfried
authors.initials: W
authors.lastname: Hermes
authors.forename: Mathias
authors.initials: M
authors.lastname: Eul
authors.forename: Clazina H
authors.initials: CH
authors.lastname: Wijbrans
authors.forename: Arno
authors.initials: A
authors.lastname: Rohrbach
authors.forename: Rainer
authors.initials: R
authors.lastname: Pöttgen