HEAT CAPACITY OF AMMONIUM CHROMIUM ALUM

Abstract

The heat capacity of 2 samples of NH4Cr(SO4)2 12H2O was measured from 18 to 305 K. A second-order transition was found in the region between 92 and 97 K with a heat and entropy of transition equal to 267.4 + or - 0.1 cal and 2.83 + or - 0.1 EU, respectively. The transition tended to disappear under supercooling conditions. The results are compared with the observations of Kraus and Nutting (J. Chem. Phys. 9; 133, 1941). The samples which showed transitions became opaque after a few minutes in the N or H cooling liquid, as though they were broken into an infinite number of tiny crystals by the disruption of the lattice. The production of the multicrystalline material was attributed to a volume change under hysteresis conditions.

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Document Details

Document Type
Technical Report
Publication Date
Apr 20, 1953
Accession Number
AD0010066

Entities

People

  • Herrick L. Johnston
  • Jih-hing Hu
  • William S Horton

Organizations

  • Ohio State University

Tags

Communities of Interest

  • Energy and Power Technologies

DTIC Thesaurus Topics

  • Absorption Spectra
  • Abstracts
  • Chemistry
  • Energy
  • Heat Capacity
  • Heat Energy
  • High Temperature
  • Hysteresis
  • Intervals
  • Low Temperature
  • Materials
  • Measurement
  • Military Research
  • Navy
  • New York
  • Physics Laboratories
  • Transitions

Readers

  • Materials Science and Engineering.
  • Quantum spin resonance or Electron Paramagnetic Resonance spectroscopy.
  • Thermal Physics or Thermal Science.