Spectrum MIR ATR spectrum of Ca-exchanged beidellite (SbCa-1) under 85% relative humidity of H2O vapor Spectrum MIR ATR spectrum of Ca-exchanged beidellite (SbCa-1) under 75% relative humidity of H2O vapor Spectrum MIR ATR spectrum of Ca-exchanged beidellite (SbCa-1) under 65% relative humidity of H2O vapor Spectrum MIR ATR spectrum of Ca-exchanged beidellite (SbCa-1) under 50% relative humidity of H2O vapor Spectrum MIR ATR spectrum of Ca-exchanged beidellite (SbCa-1) under 30% relative humidity of H2O vapor Spectrum MIR ATR spectrum of Ca-exchanged beidellite (SbCa-1) under 25% relative humidity of H2O vapor Spectrum MIR ATR spectrum of Ca-exchanged beidellite (SbCa-1) under 19% relative humidity of H2O vapor Spectrum MIR ATR spectrum of Ca-exchanged beidellite (SbCa-1) under 5% relative humidity of H2O vapor