Chromium(IV) oxide

[3] The crystal's magnetic properties, derived from its ideal shape such as anisotropy which imparted high coercivity and remanent magnetization intensities, resulted in exceptional stability and efficiency for short wavelengths, and it almost immediately appeared in high performance audio tape used in audio cassettes for which treble response and hiss were always problems.

Also introduced was a new equalization (70 μs) that traded some of the extended high-frequency response for lower noise, resulting in a 5–6 dB improvement in signal-to-noise ratio over ferric oxide audio tapes.

Later research significantly increased the coercivity of the particle by doping or adsorbing rare elements such as iridium onto the crystal matrix or by improving the axial length-to-deprecated[clarification needed] ratios.

After 500 hours of running across ferrite heads, chrome tape had polished the granular surface enough that there was no more detectable wear, and the gap edges remained sharp and distinct.

Because of its low Curie temperature of approximately 386 K (113 °C; 235 °F), chrome tape lent itself to high-speed thermomagnetic duplication of audio and video cassettes for pre-recorded product sales to the consumer and industrial markets.

Japanese competitors developed cobalt-adsorbed (TDK: Avilyn) and cobalt ferrite (Maxell: Epitaxial) "chrome equivalent" Type II audio cassettes and various videotape formats as substitutes.

In addition to BASF, which no longer owns a tape manufacturing division, Bayer AG of Germany, Toda Kogyo and Sakai Chemical of Japan also do or can produce the magnetic particles for commercial applications.

Chromium(IV) oxide
Chromium(IV) oxide
CrO 2 cassette tape